阅读说明：本技术 砂层地质土钉墙支护施工方法 (Sand layer geological soil nailing wall supporting construction method ) 是由 王凯飞 赵承民 张喆 张亮 王建斌 于 2018-01-26 设计创作，主要内容包括：本发明公开了一种砂层地质土钉成孔用吹孔装置及土钉墙支护施工方法,该吹孔装置包括空压机、沿土钉轴线方向由外向内推进待加固边坡内并对钉孔进行成孔施工的吹孔管、连接于空压机与吹孔管之间的连接软管和铺放于待加固边坡坡面上的带孔封堵板,吹孔管为与钉孔呈同轴布设的直管；该方法包括步骤：一、孔位确定；二、带孔封堵板铺放；三、吹孔；四、拔管；五、M次重复步骤三至步骤四,获得施工成型的钉孔。本发明采用与空压机送风口连接的吹风管由外至后插入坡体并进行吹孔,并结合带孔封堵板对孔口进行限位封堵,实现简便、快速在砂层中进行土钉成孔,能有效保证所成型钉孔的施工质量,并能确保边坡土钉墙支护效果。(The invention discloses a hole blowing device for forming a hole in a sand layer geological soil nail and a soil nail wall support construction method, wherein the hole blowing device comprises an air compressor, a hole blowing pipe, a connecting hose and a hole sealing plate, wherein the hole blowing pipe is pushed into a slope to be reinforced from outside to inside along the axis direction of the soil nail and is used for forming the hole in the nail hole; the method comprises the following steps: firstly, determining hole positions; secondly, laying a plugging plate with holes; thirdly, blowing holes; fourthly, drawing the tube; and fifthly, repeating the third step and the fourth step M times to obtain the nail hole for construction molding. The invention adopts the blowing pipe connected with the air supply outlet of the air compressor to insert the slope body from outside to back and blow the hole, and combines the plugging plate with the hole to perform limit plugging on the hole opening, thereby realizing simple and rapid soil nail hole forming in a sand layer, effectively ensuring the construction quality of the formed nail hole and ensuring the supporting effect of the side slope soil nailing wall.)

1. A sand bed geology soil nailing wall support construction method is characterized in that: adopting a hole blowing device for hole forming of the soil nails in the sand layer geology to carry out hole forming construction on the nail holes (8) of the soil nails to be constructed on the side slope (7) to be reinforced; the hole blowing device for the sand layer geological soil nail hole forming comprises an air compressor (1), a hole blowing pipe (4) which is pushed into a slope (7) to be reinforced from outside to inside along the axis direction of the soil nail and performs hole forming construction on a nail hole (8), a connecting hose (3) connected between the air compressor (1) and the hole blowing pipe (4), and a hole sealing plate (5) laid on the slope surface of the slope (7) to be reinforced, wherein the hole blowing pipe (4) is a straight pipe which is coaxially arranged with the nail hole (8), the diameter of the hole blowing pipe (4) is smaller than the aperture of the nail hole (8), and the length of the hole blowing pipe is larger than the length of the nail hole (8); one end of the connecting hose (3) is connected with the rear end of the hole blowing pipe (4), and the other end of the connecting hose is connected with an air supply outlet of the air compressor (1);

the plugging plate with the hole (5) is provided with a limiting hole (9); the plugging plate with the holes (5) is a flat plate and is arranged in parallel with the slope surface of the side slope (7) to be reinforced, the limiting holes (9) and the nail holes (8) are coaxially arranged, and the limiting holes (9) are round holes and have the same aperture as that of the nail holes (8); the limiting hole (9) is a through hole for the blowing hole pipe (4) to pass through;

when the hole forming construction is carried out on the nail hole (8) of the soil nail to be constructed on the side slope (7) to be reinforced, the method comprises the following steps:

step one, determining hole positions: measuring and paying off the hole position of the constructed nail hole (8);

step two, laying a plugging plate with holes: according to the hole position of the constructed nail hole (8) obtained by measuring and setting out in the step one, the plugging plate with the hole (5) is laid on the slope surface of the side slope (7) to be reinforced, and the limiting hole (9) of the plugging plate with the hole (5) and the constructed nail hole (8) are coaxially arranged;

step three, hole blowing: placing the front end of the hole blowing pipe (4) in the limiting hole (9) of the plugging plate with the hole (5) in the step two, and then pushing the hole blowing pipe (4) into the side slope (7) to be reinforced from outside to inside at a constant speed along the axis direction of the soil nail; in the propelling process of the hole blowing pipe (4), high-pressure air is continuously injected into the hole blowing pipe (4) through an air compressor (1), the injected high-pressure air enters a side slope (7) to be reinforced through the front end of the hole blowing pipe (4) to blow holes, holes which are coaxially arranged with the constructed nail holes (8) are obtained, and the depth of each hole is not less than that of the constructed nail hole (8);

in the propelling process of the hole blowing pipe (4), the soil body in the hole is blown out from inside to outside by high-pressure air entering the side slope (7) to be reinforced through the front end of the hole blowing pipe (4), and the hole wall of the hole is pressurized and reinforced by the high-pressure air entering the side slope (7) to be reinforced through the front end of the hole blowing pipe (4); meanwhile, limiting the soil body on the periphery of the hole opening of the hole through a plugging plate (5) with the hole, so that the aperture of the hole is not larger than that of the constructed nail hole (8);

step four, tube drawing: the hole blowing pipe (4) is pulled out from the side slope (7) to be reinforced from inside to outside along the axial direction of the soil nail;

step five, repeating the step three to the step four M times to obtain a nail hole (8) for construction molding; wherein M is a positive integer and M is not less than 1.

2. The sand layer geological soil nailing wall supporting construction method according to claim 1, characterized in that: and a support frame (2) for supporting the hole blowing pipe (4) is arranged on the front side of the side slope (7) to be reinforced.

3. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 2, characterized in that: the hole blowing pipe (4) is a steel pipe, and the connecting hose (3) is a nylon hose;

hole blowing device for sand layer geology soil nail pore-forming still includes coaxial suit on hole blowing pipe (4) and can follow hole blowing pipe (4) and carry out guard plate (13) of back-and-forth movement, guard plate (13) are the flat board of parallel arrangement with foraminiferous shutoff board (5).

4. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 2, characterized in that: the hole blowing device for the hole forming of the sand layer geological soil nail further comprises a wind pressure detection unit (10) for detecting the pressure of an air supply outlet of the air compressor (1) in real time and a displacement detection unit (11) for detecting the propulsion displacement of the hole blowing pipe (4) in real time, wherein the wind pressure detection unit (10) and the displacement detection unit (11) are both connected with the processor (12);

the inner side wall of the perforated plugging plate (5) is tightly attached to the slope surface of the side slope (7) to be reinforced, and the perforated plugging plate (5) is a wood plate.

5. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 2, characterized in that: the aperture of the nail hole (8) is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe (4) is phi 42 mm-phi 55mm, and the wall thickness is 2 mm-5 mm.

6. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 2, characterized in that: a concrete spraying layer (6) is arranged on the slope surface of the side slope (7) to be reinforced, round holes are formed in the concrete spraying layer (6), the round holes are located on the outer sides of the nail holes (8), the diameter of each round hole is the same as that of each nail hole (8), and the round holes and the nail holes (8) are coaxially arranged; the plugging plate with the holes (5) is tiled on the concrete spraying layer (6).

7. The sand layer geological soil nailing wall supporting construction method according to claim 1, characterized in that: the pressure of the high-pressure air in the third step is 0.75MPa to 1.25 MPa;

in the third step, when the hole blowing pipe (4) is pushed into the side slope (7) to be reinforced from outside to inside at a constant speed, the pressure between the hole blowing pipe (4) and the hole is 0.05 MPa-0.2 MPa;

in the third step, when the hole blowing pipe (4) is pushed into the side slope (7) to be reinforced from outside to inside at a constant speed, the pushing speed is 0.5m/min to 2 m/min;

and M in the step five is 1, 2, 3 or 4.

8. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 7, characterized in that: the aperture of the nail hole (8) in the first step is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe (4) in the third step is phi 42 mm-phi 55mm, and the wall thickness is 2 mm-5 mm;

when hole blowing is carried out in the third step, when the length of the hole blowing pipe (4) pushed into the side slope (7) to be reinforced is not less than the length of the constructed soil nails, the hole blowing pipe (4) stops pushing, and the hole blowing process is completed;

after the hole blowing pipe (4) stops propelling and before pipe drawing in the fourth step, high-pressure air is continuously injected into the hole blowing pipe (4) through the air compressor (1), the injected high-pressure air enters the hole bottom of the hole through the front end of the hole blowing pipe (4) and hole blowing is continuously carried out until the hole bottom of the hole forms an enlarged hole, and the aperture of the enlarged hole is not smaller than phi 200 mm.

9. The sand layer geological soil nailing wall supporting construction method according to claim 1 or 7, characterized in that: the quantity of the soil nails to be constructed on the side slope (7) to be reinforced is multiple;

before the hole blowing device is adopted to carry out hole forming construction on a nail hole (8) of a side slope (7) to be reinforced, which needs to be constructed with soil nails, a concrete spraying layer (6) is firstly sprayed on the slope surface of the side slope (7) to be reinforced, and the slope surface of the side slope (7) to be reinforced is preliminarily reinforced through the concrete spraying layer (6); then, all soil nails to be constructed on the side slope (7) to be reinforced are respectively constructed; finally, spraying a concrete spraying surface layer on the concrete spraying layer (6);

before the concrete spraying surface layer is sprayed on the concrete spraying layer (6), a layer of reinforcing mesh is hung on the concrete spraying layer (6); the outer ends of all the soil nails are fixedly connected with the reinforcing mesh, and the outer ends of all the soil nails and the reinforcing mesh are fixed in the concrete spraying surface layer;

when any soil nail on the side slope (7) to be reinforced is constructed, hole forming construction is firstly carried out according to the method in the first step to the fifth step to obtain a nail hole (8) of the soil nail; then placing the pre-processed soil nails into the nail holes (8), wherein the outer ends of the soil nails extend out of the nail holes (8); then, injecting slurry into the nail hole (8) by using a slurry injection pipe, and obtaining the soil nail formed by construction after the injected slurry is solidified; the slurry is cement slurry or cement mortar;

before the hole-in-hole plugging plate is laid in the second step, according to the hole position of the constructed nail hole (8) obtained by measuring and setting out in the first step, a round hole is formed in the concrete spraying layer (6), the round hole is located on the outer side of the constructed nail hole (8), the aperture of the round hole is the same as that of the constructed nail hole (8), and the round hole and the constructed nail hole (8) are coaxially arranged.

Technical Field

The invention belongs to the technical field of side slope support construction, and particularly relates to a hole blowing device for hole forming of soil nails in sand bed geology and a soil nail wall support construction method.

Background

The soil nailing wall is an in-situ soil body reinforcement technology. The slope of the foundation pit is reinforced by soil nails made of steel bars, a steel bar mesh is laid on the surface of the slope, and a layer of concrete surface layer is sprayed on the surface of the slope to combine with the soil slope. The soil nailing wall is constructed into a complex body formed by firmly bonding a reinforced rod piece (namely a soil nail or an anchor rod) arranged in a slope body with a surrounding soil body, and a supporting structure similar to a gravity retaining wall formed by a sprayed concrete surface layer, so that a stable foundation pit supporting form of an excavation surface is ensured. Compared with other supporting forms, the soil nailing wall support has the following advantages: the material consumption is small, and the construction speed is high; the construction equipment is light, and the operation method is simple; the adaptability to the soil layer of the field is strong; the structure is light, the flexibility is high, and the ductility is good; the required field for construction is small; the safety and the reliability are realized; economy and low cost. Thus, soil nailing walls have become a widely adopted form in foundation pit support.

The drilling and grouting nail is a soil nail which is formed by firstly drilling a hole (also called a nail hole, a soil nail hole or a soil nail hole) in a soil body by using mechanical equipment such as a drilling machine and the like, placing a reinforced rod piece after the hole is formed, and then performing construction and molding along the full length by injecting cement slurry. The drilling and grouting nail is almost suitable for various soil layers, has high pulling resistance, reliable quality and low manufacturing cost, and is the most common soil nail type. In a building engineering project, the construction difficulty of a sand layer geological drilling grouting nail is high, mainly because the hole forming difficulty of a soil nail in a sand layer (namely a sand layer) is very high, and particularly the problem of silt soil slope support is prominent, the problems of sand soil loss, deformation, foundation pit slope instability and the like are easy to occur because the soil nail wall support or the sheet pile support cannot be adopted in the conventional single support mode at present.

Disclosure of Invention

The invention aims to solve the technical problem that the hole blowing device for forming the soil nail hole in the sand layer geology is provided aiming at the defects in the prior art, a blowing pipe connected with an air supply outlet of an air compressor is inserted into a slope body from outside to back to blow the hole, and a hole plugging plate with a hole is combined to limit and plug the hole opening, so that the soil nail hole forming in the sand layer is realized simply, conveniently and quickly, and the construction quality of the formed nail hole can be effectively ensured.

In order to solve the technical problems, the invention adopts the technical scheme that: the utility model provides a sand bed geology soil nail pore-forming is with blowing hole device which characterized in that: the hole blowing pipe is a straight pipe which is coaxially arranged with the nail hole, the diameter of the hole blowing pipe is smaller than the aperture of the nail hole, and the length of the hole blowing pipe is larger than the length of the nail hole; one end of the connecting hose is connected with the rear end of the hole blowing pipe, and the other end of the connecting hose is connected with an air supply outlet of the air compressor;

the plugging plate with the holes is provided with limiting holes; the plugging plate with the holes is a flat plate and is arranged in parallel with the slope surface of the side slope to be reinforced, the limiting holes and the nail holes are coaxially arranged, and the limiting holes are round holes and have the same aperture as that of the nail holes; the limiting hole is a through hole for the blowing hole pipe to pass through.

Above-mentioned sand bed geology soil nail pore-forming is with blowing hole device, characterized by: and a support frame for supporting the hole blowing pipe is arranged on the front side of the slope to be reinforced.

Above-mentioned sand bed geology soil nail pore-forming is with blowing hole device, characterized by: the hole blowing pipe is a steel pipe, and the connecting hose is a nylon hose;

the hole blowing pipe is coaxially sleeved with a protection plate, the protection plate can move back and forth along the hole blowing pipe, and the protection plate is a flat plate arranged in parallel with the plugging plate with the holes.

Above-mentioned sand bed geology soil nail pore-forming is with blowing hole device, characterized by: the air compressor further comprises an air pressure detection unit for detecting the pressure of an air supply outlet of the air compressor in real time and a displacement detection unit for detecting the propelling displacement of the hole blowing pipe in real time, wherein the air pressure detection unit and the displacement detection unit are both connected with the processor;

the inner side wall of the perforated plugging plate is tightly attached to the slope surface of the side slope to be reinforced, and the perforated plugging plate is a wood plate.

Above-mentioned sand bed geology soil nail pore-forming is with blowing hole device, characterized by: the aperture of the nail hole is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe is phi 42 mm-phi 55mm, and the wall thickness of the hole blowing pipe is 2 mm-5 mm.

Above-mentioned sand bed geology soil nail pore-forming is with blowing hole device, characterized by: a concrete spraying layer is arranged on the slope surface of the side slope to be reinforced, round holes are arranged on the concrete spraying layer and are positioned outside the nail holes, and the diameter of each round hole is the same as that of each nail hole and is coaxially arranged with the nail holes; the perforated plugging plate is laid on the concrete spraying layer in a flatwise mode.

Meanwhile, the invention discloses a sand bed geological slope soil nailing wall support construction method which is simple in method steps, reasonable in design, simple and convenient to construct and easy to ensure the construction quality, and is characterized in that: adopt blow the hole device and treat the nail hole of needing the construction soil nail on the reinforcement slope and carry out the pore-forming construction, including following step:

step one, determining hole positions: measuring and paying off hole positions of the constructed nail holes;

step two, laying a plugging plate with holes: according to the hole position of the constructed nail hole obtained by measuring and setting out in the step one, the plugging plate with the hole is laid on the slope surface of the side slope to be reinforced, and the limiting hole of the plugging plate with the hole and the constructed nail hole are coaxially arranged;

step three, hole blowing: placing the front end of the hole blowing pipe in the limiting hole of the plugging plate with the hole in the step two, and then pushing the hole blowing pipe into the slope to be reinforced from outside to inside at a constant speed along the axis direction of the soil nail; in the process of propelling the hole blowing pipe, continuously injecting high-pressure air into the hole blowing pipe through an air compressor, enabling the injected high-pressure air to enter the side slope to be reinforced through the front end of the hole blowing pipe to blow holes, and obtaining holes coaxially distributed with the constructed nail holes, wherein the depth of each hole is not less than that of the constructed nail hole;

in the process of pushing the hole blowing pipe, the soil body in the hole is blown out from inside to outside through high-pressure air entering the side slope to be reinforced through the front end of the hole blowing pipe, and the hole wall of the hole is pressurized and reinforced through the high-pressure air entering the side slope to be reinforced through the front end of the hole blowing pipe; meanwhile, limiting the soil body on the periphery of the hole opening of the hole through a plugging plate with the hole, so that the aperture of the hole is not larger than that of the constructed nail hole;

step four, tube drawing: pulling the hole blowing pipe out of the slope to be reinforced from inside to outside along the axial direction of the soil nail;

step five, repeating the step three to the step four M times to obtain a nail hole for construction molding; wherein M is a positive integer and M is not less than 1.

The method is characterized in that: the pressure of the high-pressure air in the third step is 0.75MPa to 1.25 MPa;

in the third step, when the hole blowing pipe is pushed into the slope to be reinforced from outside to inside at a constant speed, the pressure between the hole blowing pipe and the hole is 0.05 MPa-0.2 MPa;

in the third step, when the hole blowing pipe is pushed into the side slope to be reinforced from outside to inside at a constant speed, the pushing speed is 0.5-2 m/min;

and M in the step five is 1, 2, 3 or 4.

The method is characterized in that: the aperture of the nail hole in the first step is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe in the third step is phi 42 mm-phi 55mm, and the wall thickness of the hole blowing pipe is 2 mm-5 mm;

when hole blowing is carried out in the third step, when the length of the pipe to be blown into the side slope to be reinforced is not less than the length of the constructed soil nails, the pipe to be blown stops propelling, and the hole blowing process is completed;

and after the hole blowing pipe stops propelling and before pipe drawing in the fourth step, continuously injecting high-pressure air into the hole blowing pipe through an air compressor, enabling the injected high-pressure air to enter the hole bottom of the hole through the front end of the hole blowing pipe, and continuously blowing the hole until the hole bottom of the hole forms an enlarged hole, wherein the aperture of the enlarged hole is not less than phi 200 mm.

The method is characterized in that: the quantity of the soil nails to be constructed on the side slope to be reinforced is multiple;

before the hole blowing device is adopted to carry out hole forming construction on nail holes of soil nails to be constructed on the slope to be reinforced, a concrete spraying layer is firstly sprayed on the slope surface of the slope to be reinforced, and preliminary reinforcement is carried out on the slope surface of the slope to be reinforced through the concrete spraying layer; then, respectively constructing all soil nails to be constructed on the side slope to be reinforced; finally, spraying a concrete spraying surface layer on the concrete spraying layer;

before the concrete spraying surface layer is sprayed on the concrete spraying layer, a layer of reinforcing mesh is hung on the concrete spraying layer; the outer ends of all the soil nails are fixedly connected with the reinforcing mesh, and the outer ends of all the soil nails and the reinforcing mesh are fixed in the concrete spraying surface layer;

when any soil nail on the side slope to be reinforced is constructed, hole forming construction is firstly carried out according to the method in the first step to the fifth step to obtain a nail hole of the soil nail; placing the pre-processed soil nails into the nail holes, wherein the outer ends of the soil nails extend out of the nail holes; then, injecting slurry into the nail hole by using a slurry injection pipe, and obtaining the soil nail formed by construction after the injected slurry is solidified; the slurry is cement slurry or cement mortar;

before the hole-in-hole plugging plate is laid in the second step, according to the hole position of the constructed nail hole obtained by measuring and setting out in the first step, a round hole is formed in the concrete spraying layer and is located on the outer side of the constructed nail hole, and the diameter of the round hole is the same as that of the constructed nail hole and is coaxially arranged with the constructed nail hole.

Compared with the prior art, the invention has the following advantages:

1. the hole blowing device is simple in structure, low in investment cost and convenient to install and arrange.

2. Blow the hole device and use easy and simple to handle and excellent in use effect, adopt the blowing pipe of being connected with the air compressor machine supply-air outlet to insert the slope body and blow the hole by outer to the back to combine the foraminiferous closure plate to carry out spacing shutoff to the drill way, realize portably, carry out sand bed soil nail pore-forming fast, successfully solved the difficult problem of soil nail pore-forming under the sand bed geological conditions, guaranteed the construction quality of soil nail wall, accelerated the construction progress.

3. The soil nail hole forming construction method is simple, reasonable in design and easy to control in construction process, the nail hole construction quality can be effectively guaranteed, the method has the advantages of being simple in process and simple and convenient to operate, the construction progress can be accelerated, the engineering cost is reduced, the construction task of foundation pit support can be completed safely, high in quality and efficiently, the construction quality of a soil nail wall can be effectively guaranteed, the construction speed of side slope support is improved, the method for foundation pit support in a sand layer area is simplified, the engineering cost is reduced, and good economic and social benefits are obtained.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a reference diagram of the use state of the hole blowing device.

FIG. 2 is a schematic diagram of the hole-forming state of the hole-blowing device of the present invention.

FIG. 2-1 is a schematic view of the stress state of the wall of the nail hole according to the present invention.

Fig. 3 is a schematic block diagram of the circuit of the hole blowing device of the present invention.

FIG. 4 is a flow chart of the construction method for forming holes by soil nails.

Description of reference numerals:

1-an air compressor; 2, a support frame; 3, connecting a hose;

4-blowing a hole pipe; 5-plugging plate with holes; 6-concrete spraying layer;

7, a side slope to be reinforced; 8, nailing holes; 9-limiting holes;

10-wind pressure detecting element; 11-a displacement detection unit; 12-a processor;

13-protective plate; 14-inclination detecting unit.

Detailed Description

The hole blowing device for forming the holes in the sand layer geological soil nails, as shown in fig. 1, comprises an air compressor 1, a hole blowing pipe 4 which is pushed into a slope 7 to be reinforced from outside to inside along the axis direction of the soil nails and performs hole forming construction on nail holes 8, a connecting hose 3 connected between the air compressor 1 and the hole blowing pipe 4, and a hole plugging plate 5 laid on the slope surface of the slope 7 to be reinforced, wherein the hole blowing pipe 4 is a straight pipe which is coaxially laid with the nail holes 8, the diameter of the hole blowing pipe 4 is smaller than the aperture of the nail holes 8, and the length of the hole blowing pipe 4 is larger than the length of the nail holes 8; one end of the connecting hose 3 is connected with the rear end of the hole blowing pipe 4, and the other end of the connecting hose is connected with an air supply outlet of the air compressor 1;

the plugging plate with holes 5 is provided with limiting holes 9; the plugging plate with holes 5 is a flat plate and is arranged in parallel with the slope surface of the side slope 7 to be reinforced, the limiting holes 9 and the nail holes 8 are coaxially arranged, and the limiting holes 9 are round holes and have the same aperture as that of the nail holes 8; the limiting hole 9 is a through hole for the blowing hole pipe 4 to pass through.

Both ends are all opened around blowing pipe 4, and blowing pipe 4 passes through coupling hose 3 and air compressor machine 1's supply-air outlet intercommunication.

Wherein, the side slope 7 to be reinforced is a sand layer side slope. The slope body of the sand layer side slope is a sand layer. In this embodiment, the slope body of sand bed geology side slope is the silt particle layer. The silt in the silt layer is a product of weathered rock, particles are between fine silt and silt, the particle composition of the silt is mainly sand and silt, and the content of sticky particles is relatively low.

In this embodiment, the side slope 7 to be reinforced is a foundation pit side slope, and according to a geotechnical engineering investigation report, the stratum within the excavation depth range of the foundation pit mainly consists of loess-shaped silty clay and medium sand. The excavation depth of the foundation pit is m 6-8 m, a sand layer is formed below 1 m-2 m of the ground, and the thickness of the sand layer is 4 m-6 m. The foundation pit support is in a soil nailing wall support mode, and how to form holes by soil nails in a sand layer is difficult in the soil nailing wall support and directly relates to the construction quality of the soil nailing wall in the sand layer.

According to geotechnical engineering investigation reports, loess-like powdery clay: the color is yellow brown, the soil texture is uneven, the snail shell fragments and iron and manganese stripes are seen, the snail shell fragments and the iron and manganese stripes are in a plastic state, and the thickness of the layer is 0.5-2.6 m; medium sand: gray yellow, wherein the mineral components mainly comprise quartz and feldspar, and the quartz and feldspar are loose to slightly dense, have poor gradation and have the thickness of 1.2-6.9 m; medium coarse sand: the mineral components are mainly quartz and feldspar, and have the advantages of medium density, poor grading and 5-11.0 m of layer thickness. The stable water level of the underground water is-7.2 m to-8.7 m.

During actual construction, the side slope 7 to be reinforced is arranged on a plurality of rows of soil nails from top to bottom, and the distance between every two adjacent rows of soil nails is 1.5-2.5 m. Each row of soil nails comprises a plurality of soil nails distributed on the slope 7 to be reinforced from left to right, and the distance between every two adjacent soil nails is 1.2-2.2 m. All soil nails on the slope 7 to be reinforced are arranged in parallel, and each soil nail is gradually inclined downwards from outside to inside. The length of the soil nail is 4-6 m, and the inclination angle between the horizontal planes is 10-18 degrees.

In this embodiment, the slope 7 to be reinforced is arranged on three rows of soil nails from top to bottom.

In the actual construction process, the number of rows of the soil nails arranged on the side slope 7 to be reinforced, the distance between two adjacent soil nails on the left and right, and the length and the inclination angle of the soil nails can be correspondingly adjusted according to specific requirements.

In this embodiment, the air compressor 1 is a screw air compressor for guniting, and may be another type of air compressor.

The hole blowing pipe 4 is a steel pipe, and can also be a straight pipe made of other hard materials, such as an alloy pipe. The hole blowing pipe 4 is a steel pipe, so that the cost is low, the processing and the manufacturing are simple and convenient, and the hole blowing pipe can be repeatedly used for many times. In this embodiment, the hole blowing pipe 4 is a through long steel pipe. For the convenience of use, the hole blowing pipe 4 can also be an assembled pipe formed by splicing a plurality of steel pipe joints from front to back, the pipe diameters of the steel pipe joints are the same and are coaxially arranged, and the adjacent two steel pipe joints are fastened and connected through threaded connection joints.

In this embodiment, the connecting hose 3 is a nylon hose, has low input cost, is simple and convenient to connect, is firm and durable, can be repeatedly used, and can effectively meet the requirement of continuously injecting high-pressure air.

In practice, the connecting hose 3 may be other types of hoses, such as metal hoses.

In this embodiment, the length of the blowhole pipe 4 is greater than the length of the soil nail.

As shown in fig. 2, in the actual use process, high-pressure air is continuously injected into the hole blowing pipe 4 through the air compressor 1, and the injected high-pressure air enters the side slope 7 to be reinforced through the front end (namely the front port) of the hole blowing pipe 4 to blow holes, specifically, soil (namely sandy soil) in front of the hole blowing pipe 4 on the side slope 7 to be reinforced is blown away to form holes, and the holes are gradually inserted into the formed holes from outside to inside along with the hole blowing pipe 4, and the soil in the holes is blown out along the advancing direction of the air flow, so that a hole is gradually formed in the sand layer of the side slope 7 to be reinforced along the advancing direction of the hole blowing pipe 4.

As shown in fig. 2-1, during the pore-forming process, high-pressure air is continuously conveyed into the hole through the pore-blowing pipe 4, air pressure is formed in the hole during the process that the pore-blowing pipe 4 is pushed into the sand layer from outside to inside, and extrusion force is applied to the hole wall of the formed hole during pore-forming, so that the bearing capacity of the hole wall is enhanced, and after the pore-blowing pipe 4 is pulled out of the hole after pore-forming is finished, the inner wall of the hole cannot collapse within a certain time.

In the embodiment, the hole blowing device for forming the hole in the sand layer geological soil nail further comprises a protection plate 13 which is coaxially sleeved on the hole blowing pipe 4 and can move back and forth along the hole blowing pipe 4, and the protection plate 13 is a flat plate which is arranged in parallel with the hole plugging plate 5.

During actual construction, the protection plate 13 can effectively prevent soil blown out of the hole from damaging constructors and construction equipment. In this embodiment, the distance between the protection plate 13 and the plugging plate with holes 5 is 0.15m to 0.5 m. And a soil discharging channel for discharging soil blown out from the holes is arranged between the protection plate 13 and the plugging plate 5 with the holes.

In this embodiment, the protection plate 13 is a circular wood plate, the diameter of the protection plate is larger than the diameter of the nail hole 8, and the middle part of the protection plate 13 is provided with a mounting hole for mounting the blowing hole pipe 4.

In this embodiment, a support frame 2 for supporting the hole blowing pipe 4 is arranged on the front side of the slope 7 to be reinforced.

For construction convenience, the support frame 2 is a scaffold assembled by a plurality of rod pieces.

The support frame 2 is close to one side upper portion of treating consolidating side slope 7 and is provided with the slope support that carries out the support to blowing hole pipe 4, through the adjustment the inclination of slope support can carry out simple and convenient, quick adjustment to the inclination of blowing hole pipe 4 to can effectively guarantee the inclination in the shaping nail hole 8.

In the embodiment of the invention, the hole blowing device for forming the hole in the sand layer geological soil nail further comprises a pushing device for pushing the hole blowing pipe 4 to move linearly back and forth, and the pushing device and the rear section of the hole blowing pipe 4 are pushing sections. The pushing device is an electric pushing mechanism and is connected with the pushing section.

The front section of the hole blowing pipe 4 is an insertion section, and the hole blowing pipe 4 is formed by connecting the insertion section and the pushing section. The length of the insertion section is not less than that of the soil nails.

When actually carrying out pore-forming construction, only need observe the length of current shaping hole can accurately be known to the inserted length of inserting the section, and the operability is stronger.

In this embodiment, the length of the insertion section is the same as the length of the soil nail.

In actual construction, the hole blowing pipe 4 may be manually pushed to linearly move forward and backward.

In this embodiment, as shown in fig. 3, the hole blowing device for forming a hole in a sand layer geological soil nail further includes a wind pressure detecting unit 10 for detecting the pressure of the air supply outlet of the air compressor 1 in real time and a displacement detecting unit 11 for detecting the pushing displacement of the hole blowing pipe 4 in real time, and both the wind pressure detecting unit 10 and the displacement detecting unit 11 are connected to the processor 12.

Meanwhile, the hole blowing device for forming the holes in the sand layer geological soil nails further comprises an inclination angle detection unit 14 for detecting the inclination angle of the hole blowing pipe 4 in real time, and the inclination angle detection unit 14 is connected with the processor 12.

In the actual hole blowing process, the pressure of the air supply outlet of the air compressor 1 is detected in real time through the air pressure detection unit 10, and the detected information is synchronously transmitted to the processor 12, so that the pressure of the currently conveyed high-pressure gas is simply, quickly, in real time and accurately known; the displacement detection unit 11 is used for detecting the propelling displacement of the hole blowing pipe 4 in real time and synchronously transmitting the detected information to the processor 12, so that the length of the current formed hole can be simply, conveniently, quickly, in real time and accurately known; meanwhile, the inclination angle of the hole blowing pipe 4 is detected in real time through the inclination angle detection unit 14, and the detected information is synchronously transmitted to the processor 12, so that the inclination angle of the current formed hole can be simply, conveniently, quickly, in real time and accurately known. Therefore, the actual operation is very simple and convenient, and the hole blowing quality can be effectively ensured.

In this embodiment, the inner side wall of the plugging plate with holes 5 is tightly attached to the slope surface of the side slope 7 to be reinforced.

During actual construction, the position and the aperture of the formed nail hole can be effectively ensured through the plugging plate with the hole 5.

In order to simplify the construction and effectively ensure that the effect of the perforated plugging plate 5 can be fully and effectively exerted, the hole blowing device for the hole forming of the sand layer geological soil nail further comprises a supporting device for supporting the perforated plugging plate 5 from outside to inside and enabling the inner side wall of the perforated plugging plate 5 to be tightly attached to the slope surface of the side slope 7 to be reinforced. In this embodiment, the supporting device is a hydraulic jack.

In the actual pore-forming process, it is right through foraminiferous shutoff board 5 the soil body of hole drill way week side carries on spacingly, can effectively prevent on the one hand that the drill way from collapsing the hole, and on the other hand carries out the roof pressure to the soil body of hole week side from outer to inner through foraminiferous shutoff board 5, and this roof pressure matches with the extrusion force that lasts to carrying highly-compressed air in the hole for the shaping hole pore wall through blowing hole pipe 4, further guarantees the quality of shaping hole for the shaping hole is more firm, can effectively prevent to collapse the hole. Meanwhile, the hole site soil body of the currently constructed nail hole 8 on the side slope 7 to be reinforced can be effectively stabilized by adopting the plugging plate with the hole 5, the influence of the nail hole 8 on the other areas on the side slope 7 to be reinforced in the hole forming process can be effectively reduced, and the overall stability of the side slope 7 to be reinforced is ensured.

In this embodiment, the plugging plate with holes 5 is a wood plate, so that the actual support is simple and convenient, and the investment cost is low.

In the embodiment, the aperture of the nail hole 8 is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe 4 is phi 42 mm-phi 55mm, and the wall thickness is 2 mm-5 mm.

During actual construction, the aperture of the nail hole 8 and the outer diameter and the wall thickness of the hole blowing pipe 4 can be adjusted correspondingly according to specific requirements. Generally, the larger the diameter of the nail holes 8, the larger the outer diameter of the blowhole pipe 4 and the larger the wall thickness thereof.

In the embodiment, in order to ensure the stability of the side slope 7 to be reinforced, before blowing the holes, a concrete spraying layer 6 is arranged on the slope surface of the side slope 7 to be reinforced, a circular hole is arranged on the concrete spraying layer 6 and is positioned outside the nail hole 8, and the diameter of the circular hole is the same as that of the nail hole 8 and is coaxially arranged with the nail hole 8; the perforated plugging plate 5 is tiled on the concrete spraying layer 6.

When the hole blowing device for hole forming of the sand layer geological soil nails is used for carrying out soil nail wall support construction on the sand layer geological side slope, as shown in figure 4, the hole blowing device is used for carrying out hole forming construction on the nail holes 8 of the soil nails to be constructed on the side slope 7 to be reinforced, and the hole blowing device comprises the following steps:

step one, determining hole positions: measuring and paying off the hole position of the constructed nail hole 8;

step two, laying a plugging plate with holes: according to the hole position of the constructed nail hole 8 obtained by measuring and setting out in the step one, the plugging plate with holes 5 is laid on the slope surface of the side slope 7 to be reinforced, and the limiting hole 9 of the plugging plate with holes 5 and the constructed nail hole 8 are coaxially arranged;

step three, hole blowing: placing the front end of the hole blowing pipe 4 in the limiting hole 9 of the plugging plate with holes 5 in the step two, and then pushing the hole blowing pipe 4 into the side slope 7 to be reinforced from outside to inside at a constant speed along the axial direction of the soil nail; in the propelling process of the hole blowing pipe 4, high-pressure air is continuously injected into the hole blowing pipe 4 through the air compressor 1, the injected high-pressure air enters the side slope 7 to be reinforced through the front end of the hole blowing pipe 4 to blow holes, holes which are coaxially arranged with the constructed nail holes 8 are obtained, and the depth of each hole is not less than that of the constructed nail hole 8;

in the process of pushing the hole blowing pipe 4, the soil body in the hole is blown out from inside to outside by high-pressure air entering the side slope 7 to be reinforced through the front end of the hole blowing pipe 4, and the hole wall of the hole is pressurized and reinforced by the high-pressure air entering the side slope 7 to be reinforced through the front end of the hole blowing pipe 4; meanwhile, limiting the soil body on the periphery of the hole opening of the hole by a plugging plate 5 with the hole, so that the aperture of the hole is not larger than that of the constructed nail hole 8;

step four, tube drawing: the hole blowing pipe 4 is pulled out from the side slope 7 to be reinforced from the inside to the outside along the axial direction of the soil nail;

step five, repeating the step three to the step four M times to obtain a nail hole 8 for construction molding; wherein M is a positive integer and M is not less than 1.

In this embodiment, M in step five is 1, 2, 3, or 4.

During actual construction, the value of M can be correspondingly adjusted according to specific requirements. The construction quality of the formed nail hole 8 can be effectively ensured by repeating the steps three to four for M times. And when the third step and the fourth step are repeated every time, the hole blowing pipe 4 is pushed into the hole formed by the last hole blowing construction from outside to inside at a constant speed along the axis direction of the soil nail, and further hole forming construction is carried out.

In this embodiment, the pressure of the high pressure air in the third step is 0.75MPa to 1.25 MPa.

And in the third step, when the hole blowing pipe 4 is pushed into the side slope 7 to be reinforced from outside to inside at a constant speed, the pressure between the hole blowing pipe 4 and the hole is 0.05 MPa-0.2 MPa.

And in the third step, when the hole blowing pipe 4 is pushed into the side slope 7 to be reinforced from outside to inside at a constant speed, the pushing speed is 0.5-2 m/min. Wherein the advancing speed is the advancing speed along the axis direction of the soil nails.

During actual construction, the pressure of the high-pressure air and the propelling speed of the hole blowing pipe 4 can be adjusted correspondingly according to specific requirements. Generally, the larger the aperture of the nail hole 8, the higher the density of the sand layer of the slope 7 to be reinforced, the higher the pressure of the high-pressure air, and the slower the advancing speed of the hole blowing pipe 4.

And the aperture of the nail hole 8 in the step one is phi 100 mm-phi 150mm, the outer diameter of the hole blowing pipe 4 in the step three is phi 42 mm-phi 55mm, and the wall thickness is 2 mm-5 mm.

And in the third step, when the hole is blown, the hole blowing pipe 4 is pushed into the side slope 7 to be reinforced to a length not less than the length of the constructed soil nails, and the hole blowing pipe 4 stops pushing to complete the hole blowing process.

In the embodiment, the aperture of the hole in the third step is the same as that of the constructed nail hole 8;

and when hole blowing is carried out in the third step, the hole blowing process is completed when the length of the pipe 4 to be blown into the side slope 7 to be reinforced is the same as that of the constructed soil nails.

In this embodiment, the number of the soil nails to be constructed on the slope 7 to be reinforced is plural.

Before the hole blowing device is adopted to carry out hole forming construction on a nail hole 8 of a soil nail to be constructed on a side slope 7 to be reinforced, a layer of concrete spraying layer 6 is sprayed on the slope surface of the side slope 7 to be reinforced, and preliminary reinforcement is carried out on the slope surface of the side slope 7 to be reinforced through the concrete spraying layer 6; then, all the soil nails to be constructed on the side slope 7 to be reinforced are respectively constructed; finally, spraying a concrete spraying surface layer on the concrete spraying layer 6;

before the concrete spraying surface layer is sprayed on the concrete spraying layer 6, a layer of reinforcing mesh is hung on the concrete spraying layer 6; the outer ends of all the soil nails are fixedly connected with the reinforcing mesh, and the outer ends of all the soil nails and the reinforcing mesh are fixed in the concrete spraying surface layer.

During actual construction, firstly excavating the foundation pit and obtaining the side slope 7 to be reinforced, wherein disturbance on the slope surface of the side slope 7 to be reinforced is reduced as much as possible during excavation; and after the foundation pit is excavated, finishing the slope surface of the side slope 7 to be reinforced, and removing the deficient soil on the slope surface. In this embodiment, the slope gradient of the side slope 7 to be reinforced is 1: 0.6.

Because the slope surface of the sand layer is easy to be disturbed, the initial guniting (namely the concrete spraying layer 6) is required to be carried out immediately on the excavated slope surface, so that the surface of the slope 7 to be reinforced is solidified to reinforce the slope surface, and the stability of the slope surface is ensured in the subsequent construction process. The concrete spraying layer 6 is a concrete primary spraying layer. Therefore, the construction of the concrete sprayed layer 6 is required to be performed in time to enhance the stability of the slope and to seal the slope surface. The concrete spraying layer 6 is a thin concrete layer and the thickness of the concrete spraying layer is 3 cm-10 cm.

During actual construction, hang on concrete injection layer 6 and establish during the reinforcing bar net, both can be after concrete injection layer 6 construction is accomplished and the injected concrete solidifies, hang before treating to consolidate the slope 7 and go up the construction of soil nail and establish, also can hang after all the construction of soil nail are accomplished on treating to consolidate the slope 7 and establish.

In this embodiment, the steel bar mesh is hung before the soil nailing construction on the side slope 7 to be reinforced, the hanging of the steel bar mesh is the same as the hanging method of the steel bar mesh in the conventional soil nailing wall construction, the steel bar mesh is firmly fixed on the side wall of the side slope 7 to be reinforced, and the steel bar mesh is fixed by inserting the steel bar on the side slope 7 to be reinforced.

And after the concrete sprayed in the concrete spraying layer 6 is solidified, constructing the soil nails to be constructed on the side slope 7 to be reinforced.

When the hole blowing is carried out in the third step, after the air compressor 1 is started, soil (sand) in the formed hole (sand hole) is blown out of the hole along the high-pressure air flowing direction 9, and the high-pressure air synchronously generates extrusion force on the hole wall of the hole, so that the hole wall of the hole cannot collapse temporarily. The hole blowing pipe 4 is gradually inserted into the hole along with the continuous blowing of the sandy soil from the hole, after the depth of the hole blowing pipe 4 reaches the design requirement, the hole blowing pipe 4 is slowly pulled out of the hole, and the operation is repeatedly carried out for M times until the soil nail hole (namely the nail hole 8) is formed.

When any soil nail on the side slope 7 to be reinforced is constructed, hole forming construction is firstly carried out according to the method in the first step to the fifth step to obtain a nail hole 8 of the soil nail; placing the pre-processed soil nails into the nail holes 8, wherein the outer ends of the soil nails extend out of the nail holes 8; then, injecting slurry into the nail hole 8 by using a slurry injection pipe, and obtaining the soil nail formed by construction after the injected slurry is solidified; the slurry is cement slurry or cement mortar. Wherein the cement paste is cement paste.

During actual construction, when grout is injected into the nail hole 8 using a grout pipe, full-hole grouting (also referred to as grouting) is performed into the nail hole 8. Wherein the soil nails are placed in the nail holes 8, also called soil nail placement. In this embodiment, the soil nail is a straight reinforcing bar. Before the pre-processed soil nail is placed into the nail hole 8, the grouting pipe is fixed on the soil nail, and the grouting pipe is synchronously placed into the nail hole 8 along with the soil nail.

In this embodiment, a plurality of positioning clips for guiding are welded and fixed on the soil nail from front to back. When the soil nails are placed into the nail holes 8, the grouting pipes are brought to the positions 0.3m away from the hole bottoms through the soil nails, and then grouting is performed. During pouring, the nail hole 8 must be filled with water, and no cavity or gap can be formed.

In the actual construction process, after grouting is finished in the nail hole 8, the outer end of the soil nail is welded and fixed with reinforcing steel bars, and the soil nail and the reinforcing mesh are fastened and reliably connected through the reinforcing steel bars. And after the reinforcing steel bars on all the soil nails are welded, spraying the concrete spraying surface layer.

In this embodiment, the concrete sprayed layer 6 and the concrete sprayed surface layer form a concrete sprayed layer, and the thickness of the concrete sprayed layer is 60cm to 80 cm.

In this embodiment, after the concrete sprayed layer 6 is constructed, the hole sites of all the nail holes 8 of the soil nails to be constructed on the side slope 7 to be reinforced are respectively measured, and the hole sites of all the nail holes 8 obtained by measurement and setting-out are respectively marked on the concrete sprayed layer 6.

When the hole position of each nail hole 8 is marked, the center position and the contour line of the nail hole 8 are marked on the concrete spray layer 6.

In this embodiment, before the tube drawing in the fourth step, the air compressor 1 is first closed.

In this embodiment, before the hole-in-hole plugging plate is laid in the second step, a circular hole is formed in the concrete spraying layer 6 according to the hole position of the constructed nail hole 8 obtained by measuring and setting out in the first step, the circular hole is located outside the constructed nail hole 8, and the diameter of the circular hole is the same as that of the constructed nail hole 8 and is coaxially arranged with the constructed nail hole 8.

During actual construction, in the third step, the high-pressure air drives the sandy soil to blow out from the hole along the flow direction of the high-pressure air (namely the flow direction of the high-pressure air in the annular cavity between the hole and the hole blowing pipe 4), meanwhile, extrusion force is formed on the hole wall, so that the hole wall cannot be temporarily collapsed, and soil nails are timely arranged and grouted after the nail holes 8 are formed. The grouting method is the same as that adopted by the conventional soil nailing wall. The soil nail adopts pressure slip casting, must fill whole nail hole 8 during slip casting to the stability that influences the soil nail wall of the effect that weakens the soil nail.

In this embodiment, after the nail hole 8 is formed, soil nails are timely arranged and grouted, specifically, the soil nails are arranged and grouted within 1 hour, so as to prevent the change of the water content of the sand layer in the hole from causing hole collapse. Holes which can not be grouted in time need to be sealed by plastic cloth or templates and the like, so as to keep the humidity in the holes and prevent the holes from collapsing due to the change of water in the holes or the surface weathering of the sand layer on the inner wall.

In this embodiment, after the hole blowing pipe 4 stops being pushed and before the pipe is pulled out in the fourth step, high-pressure air is continuously injected into the hole blowing pipe 4 through the air compressor 1, and the injected high-pressure air enters the hole bottom of the hole through the front end of the hole blowing pipe 4 to continuously blow the hole until an enlarged hole is formed at the hole bottom of the hole, wherein the hole diameter of the enlarged hole is not less than phi 200 mm. The enlarged hole is a spherical hole connected with the front end of the nail hole 8.

Thus, after grouting is completed in the drill hole 8, an enlarged head is formed in the enlarged hole, and the anchoring force of the soil nail can be further increased.

During actual construction, when the foundation pit side slope is a side slope with the height larger than 8m, the foundation pit side slope is excavated in layers from top to bottom, and after each layer of excavation is finished, the side slope (namely the side slope 7 to be reinforced) formed by excavation is supported according to the soil nailing wall supporting method provided by the invention. And excavating the next layer after the strength of the sprayed concrete in the concrete spraying surface excavated and supported by the previous layer reaches 80% of the designed strength. The maximum excavation depth of each layer depends on the capability of self-stabilization of the soil wall without slippage and damage before the support is put into operation, and the excavation depth of each layer of the foundation pit is equal to the vertical distance between the soil nails.

When the foundation pit side slope is a side slope with the length larger than 20m, dividing the foundation pit side slope into a plurality of slope sections from front to back along the length direction, wherein the length of each slope section is 10-15 m, and the length of each slope section depends on the self-stability capability of the soil wall; and dividing the slope sections into a first-stage slope section and a second-stage slope section, wherein the first-stage slope section and the second-stage slope section are alternately arranged. During actual construction, all the first-stage slope segments are excavated synchronously, and the excavated first-stage slope segments (namely the side slopes 7 to be reinforced) are supported according to the soil nailing wall supporting method. And after the strength of the sprayed concrete in the concrete spraying surface after the support on all the first-stage slope sections reaches 80% of the designed strength, synchronously excavating all the second-stage slope sections, and supporting the excavated second-stage slope sections (namely the side slopes 7 to be reinforced) according to the soil nailing wall supporting method provided by the invention.

When the area of the foundation pit is large, the free excavation is allowed in the middle of the foundation pit 8-10 m away from the side slope around the foundation pit, but the free excavation is coordinated with the excavation of the layered operation area.

When actual excavation is carried out, excavating equipment with small disturbance on a slope soil body is selected for excavating soil, and the phenomenon that the side wall is over-excavated or the side wall soil body is loosened is avoided; after mechanical excavation, the slope surface is cut and cleared manually so that the slope and the slope surface flatness meet the design requirements; and after the soil nail construction is finished, clearing the slope.

According to the above content, the hole blowing device is adopted to blow holes in the sand layer side slope, and then soil nail placement and grouting are carried out, so that a plurality of soil nails are used for supporting the side slope 7 to be reinforced; meanwhile, the slope surface is sealed by combining the reinforcing mesh and the concrete spraying layer, so that the soil body of the side slope is further reinforced, and the side slope is prevented from being unstable due to liquefaction of sandy soil caused by rainwater.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.