阅读说明：本技术 埋地管道牵引穿越施工方法 (Construction method for pulling and passing buried pipeline ) 是由 李学庆 孔庆宝 李海龙 杨孟伟 张广 孙守钱 于 2019-09-05 设计创作，主要内容包括：本发明公开了埋地管道牵引穿越施工方法,属于管道施工领域。埋地管道牵引穿越施工方法,主要包括以下步骤：S1、根据设计图纸和实际勘察确定入土点和出土点；S2、根据设计图纸的钻孔轨迹设计,准备所需长度的管道；S3、钻导向孔采用钻头射流辅助进行钻进,本发明较好地适应不同铺设管线设计深度和不同施工场地条件；拖管轨迹准确、精度高,满足设计要求；在整个施工过程中,在地面上随时可确定管线的位置及埋深,满足管道的工作安全的要求,钻孔设计轨迹既平缓,曲线段又要圆滑,适用于地下管网分布复杂地段的地下管道牵引穿越施工,确保管线施工的成功,亦适用乱石、回填土等复杂的地质结构。(The invention discloses a construction method for pulling and passing through a buried pipeline, and belongs to the field of pipeline construction. The construction method for pulling and crossing the buried pipeline mainly comprises the following steps: s1, determining an earth entry point and an earth exit point according to a design drawing and actual investigation; s2, designing according to the drilling track of the design drawing, and preparing a pipeline with the required length; s3, drilling a guide hole by adopting drill bit jet flow for assisting drilling, and the method is well suitable for different design depths of laid pipelines and different construction site conditions; the pipe dragging track is accurate, the precision is high, and the design requirement is met; in the whole construction process, the position and the burial depth of the pipeline can be determined on the ground at any time, the requirement of the working safety of the pipeline is met, the drilling design track is smooth, the curve section is smooth, the method is suitable for underground pipeline traction crossing construction of underground pipe networks in complicated distribution sections, the success of pipeline construction is ensured, and the method is also suitable for complicated geological structures such as riprap, backfill and the like.)

1. The construction method for pulling and crossing the buried pipeline is characterized by mainly comprising the following steps:

s1, determining an earth entry point and an earth exit point according to a design drawing and actual investigation;

s2, designing according to the drilling track of the design drawing, and preparing a pipeline with the required length;

s3 drilling guide holes

Adopt drill bit efflux to assist and creep into, specifically do: adopting high-pressure slurry jet flow erosion crushing rotary cutting of a drill bit to form a guide hole, and controlling the drilling direction by using a 15-degree inclined-plane drill bit;

drilling at the soil-entering point, wherein the drill bit is driven by the drilling machine to rotate under the action of the thrust of the drilling machine and the pressure of slurry, and the soil layer is cut and the ruler is continuously advanced;

if the rotation and the feeding are carried out simultaneously in the drilling process, the guided drilling is linear drilling;

if the drill bit is fed and does not rotate, the deflecting drilling is implemented under the action of the 15-degree inclined plane reaction force of the drill bit, and the accurate position and state of the drill bit and the direction of the inclined plane drill bit are determined and determined according to a signal transmitter and a ground positioning tracer in a drill bit cavity;

measuring the drill bit once each drill rod is drilled, and directing an operator of the drilling machine to adjust drill bit parameters according to the measured parameters and adjust the drilling direction of the drill bit in time so as to control the drill bit to drill according to a designed track, ensure the finished pilot hole until the preset position of the drill bit is unearthed and finish the drilling work of the whole pilot hole;

s4, reaming

Combining a drill rod, a reamer, a transfer case and the drill rod into a pre-reaming drilling tool, jetting a soil layer by using high-pressure slurry to loosen the soil layer, extruding the soil layer to form a hole by using a conical drill bit of the reaming drilling tool under the action of rotation and tension, simultaneously jetting a large amount of slurry into a back reaming hole, conveying cut soil scraps to the ground to play a reaming role and forming a track hole;

the mud is mixed with a lubricant, soda ash, a diamond thickener and a biopolymer;

s5, drawing through pipeline

After reaming, a reamer, a universal rotary joint and a U-shaped ring are installed by a hoisting machine in a matching way, the reamer with the diameter being 1.5 times of that of the pipeline is firmly connected with a steel pipe with the diameter being 1 time of that of the pipeline by a transfer case, and then the pipeline in the step S2 is dragged into the track hole formed in the step S4 under the matching of the hoisting machine and the rotary traction of the drilling machine until the pipeline is pulled to a pre-laying position at the side of the drilling machine;

and S6, welding and butting the traction pipeline with the pipelines at two sides after the traction pipeline is in place, and finishing pipeline traction.

2. The underground pipeline traction crossing construction method according to claim 1, wherein when reaming is performed in step S4, two pre-reaming operations are performed for laying a steel pipe with an outer diameter Φ 426 mm:

reaming for the first time: connecting a phi 300mm reamer to the rear end of a drilling machine, then rotationally pulling back the reamer by the drilling machine for reaming, unloading one drill rod on one side of an earth entering point after each drill rod is reamed, installing one drill on one side of an earth discharging point, and repeating the steps until the phi 300mm reamer is reamed; injecting slurry while reaming;

and (5) reaming for the second time: and (4) unloading the phi 300mm reamer, replacing the phi 600mm reamer for back expansion, and simultaneously injecting mud.

3. The underground pipeline traction crossing construction method as claimed in claim 2, wherein in the drilling process of the drilling machine in the steps S4 and S5, if the drilling is stopped, a proper amount of slurry is still injected, so that positive pressure is always present in the hole, and cuttings in the hole are conveyed out.

4. The construction method for pulling and passing through the buried pipeline according to claim 1, wherein the slurry is mainly bentonite, and the lubricant agent mixed in the slurry is natural clay fine powder.

5. The underground pipeline traction crossing construction method as claimed in any one of claims 1 to 4, wherein after the soil entry point and the soil exit point are determined in step S1, the elevation and the horizontal distance of the soil entry point and the soil exit point at the construction site are retested, and a level gauge is used to cross the horizontal length position on the ground surface of the central line after the correction according to the length and the inclination of each drill rod, and the soil entry point and the soil exit point are respectively provided with a marker pile sprayed with red paint, and the elevation is measured pile by pile.

6. The construction method for pulling and passing through the buried pipeline according to claim 5, wherein after the elevation is measured pile by pile, the side line piles of the working area, the approach road, the working pit of the pipeline soil-entering point and the installation position of the drilling machine are discharged, and the gray line is sprayed as an obvious range mark; and (3) discharging side line piles at one end of the unearthed point according to the central line of the pipeline, the occupied land width and length, the length and width of a working pit of the unearthed point of the pipeline and the length and width of the discharge ditch, then sowing white ash along the edge to form a side line, marking an unearthed point operation area, and completing measurement preparation work before construction.

7. A method of buried pipeline pull through construction according to any one of claims 1 to 4 wherein in step S2 reinforcing bars are welded to the pipeline according to the size of the pipe orifice.

8. A method of buried pipeline pull through construction according to any one of claims 1 to 4 wherein a working pit is mechanically excavated at the point of entry and exit for the placement of slurry before drilling at step S3.

9. A buried pipeline traction crossing construction method according to any one of claims 1 to 4, wherein before drilling in step S3, trial injection of drilling rig mud is carried out, and the drilling rig drills 2-3 drill rods in trial.

10. The buried pipeline traction crossing construction method as claimed in any one of claims 1 to 4, wherein after the butt welding of the step S6 is completed, nondestructive testing is performed and anticorrosion and heat preservation treatment is performed.

Technical Field

The invention relates to the technical field of pipeline construction, in particular to a construction method for pulling and passing through a buried pipeline.

Background

In recent years, due to social development, old city reconstruction, new rural construction and the like, the requirements on heat supply quantity and heat supply quality are continuously improved, so that municipal heat supply pipe networks are continuously expanded and reconstructed; the buried heat supply pipe network can certainly cross roads or rivers, if traditional road excavation is adopted, the construction of the overhead mode above the rivers not only influences the traffic, still needs a large amount of manpower and material resources to find out the concrete position of the existing pipeline on both sides of the road, so both time and energy are wasted, and the control of the time limit for a project is not facilitated.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a construction method for pulling and passing through a buried pipeline.

In order to achieve the purpose, the invention adopts the following technical scheme:

the construction method for pulling and crossing the buried pipeline mainly comprises the following steps:

s1, determining an earth entry point and an earth exit point according to a design drawing and actual investigation;

s2, designing according to the drilling track of the design drawing, and preparing a pipeline with the required length;

s3 drilling guide holes

Adopt drill bit efflux to assist and creep into, specifically do: adopting high-pressure slurry jet flow erosion crushing rotary cutting of a drill bit to form a guide hole, and controlling the drilling direction by using a 15-degree inclined-plane drill bit;

drilling at the soil-entering point, wherein the drill bit is driven by the drilling machine to rotate under the action of the thrust of the drilling machine and the pressure of slurry, and the soil layer is cut and the ruler is continuously advanced;

if the rotation and the feeding are carried out simultaneously in the drilling process, the guided drilling is linear drilling;

if the drill bit is fed and does not rotate, the deflecting drilling is implemented under the action of the 15-degree inclined plane reaction force of the drill bit, and the accurate position and state of the drill bit and the direction of the inclined plane drill bit are determined and determined according to a signal transmitter and a ground positioning tracer in a drill bit cavity;

measuring the drill bit once each drill rod is drilled, and directing an operator of the drilling machine to adjust drill bit parameters according to the measured parameters and adjust the drilling direction of the drill bit in time so as to control the drill bit to drill according to a designed track, ensure the finished pilot hole until the preset position of the drill bit is unearthed and finish the drilling work of the whole pilot hole;

s4, reaming

Combining a drill rod, a reamer, a transfer case and the drill rod into a pre-reaming drilling tool, jetting a soil layer by using high-pressure slurry to loosen the soil layer, extruding the soil layer to form a hole by using a conical drill bit of the reaming drilling tool under the action of rotation and tension, simultaneously jetting a large amount of slurry into a back reaming hole, conveying cut soil scraps to the ground to play a reaming role and forming a track hole;

the mud is mixed with a lubricant, soda ash, a diamond thickener and a biopolymer;

s5, drawing through pipeline

After reaming, a reamer, a universal rotary joint and a U-shaped ring are installed by a hoisting machine in a matching way, the reamer with the diameter being 1.5 times of that of the pipeline is firmly connected with a steel pipe with the diameter being 1 time of that of the pipeline by a transfer case, and then the pipeline in the step S2 is dragged into the track hole formed in the step S4 under the matching of the hoisting machine and the rotary traction of the drilling machine until the pipeline is pulled to a pre-laying position at the side of the drilling machine;

and S6, welding and butting the traction pipeline with the pipelines at two sides after the traction pipeline is in place, and finishing pipeline traction.

Preferably, when the hole expanding is performed in step S4, two pre-hole expanding operations are performed for the steel pipe with the laid outer diameter Φ 426 mm:

reaming for the first time: connecting a phi 300mm reamer to the rear end of a drilling machine, then rotationally pulling back the reamer by the drilling machine for reaming, unloading one drill rod on one side of an earth entering point after each drill rod is reamed, installing one drill on one side of an earth discharging point, and repeating the steps until the phi 300mm reamer is reamed; injecting slurry while reaming;

and (5) reaming for the second time: and (4) unloading the phi 300mm reamer, replacing the phi 600mm reamer for back expansion, and simultaneously injecting mud.

Preferably, in the drilling process of the drilling machine in the step S4 and the step S5, if the drilling is stopped, a proper amount of slurry is still injected, so as to ensure that positive pressure is always present in the hole, and the cuttings in the hole are conveyed out.

Preferably, the mud is mainly bentonite, and the lubricant agent mixed in the mud is natural clay fine powder.

Preferably, after the soil entry point and the soil exit point are determined in step S1, the elevation and the horizontal distance of the soil entry point, the soil exit point and the elevation of the construction site are retested, and the elevation is measured pile by arranging the red paint sprayed marker piles on the ground surface of the center line, the horizontal length position of the center line which is calibrated according to the length and the inclination of each drill rod, and the soil entry point and the soil exit point.

Preferably, after the elevation is measured pile by pile, discharging side line piles of a drilling work area, an approach road, a work pit of a pipeline soil-entry point and a drilling machine installation position, and spraying a gray line as an obvious range mark; and (3) discharging side line piles at one end of the unearthed point according to the central line of the pipeline, the occupied land width and length, the length and width of a working pit of the unearthed point of the pipeline and the length and width of the discharge ditch, then sowing white ash along the edge to form a side line, marking an unearthed point operation area, and completing measurement preparation work before construction.

Preferably, in step S2, the reinforcing ribs are welded to the pipe according to the size of the pipe orifice.

Preferably, before drilling in step S3, a working pit is mechanically excavated at the earth entry and exit points for placing mud.

Preferably, before the drilling in the step S3, the drilling machine performs trial injection of the drilling mud, and the drilling machine performs trial drilling on 2-3 drill rods.

Preferably, after the butt welding in step S6 is completed, nondestructive testing is performed, and corrosion-resistant and heat-insulating treatment is performed.

Compared with the prior art, the invention provides a construction method for pulling and crossing buried pipelines, which has the following beneficial effects:

1. the construction method for the traction crossing of the buried pipeline comprises the following steps of measuring and determining the accurate position and state of a drill bit and the direction of an inclined plane drill bit according to a signal transmitter and a ground positioning tracer in a drill bit cavity in the traction crossing process; measuring a drill bit once each drill rod is drilled, and directing an operator of the drilling machine to adjust drill bit parameters according to the measured parameters and adjust the drilling direction of the drill bit in time so as to control the drill bit to drill according to a designed track, ensure the finished guide hole and control the drilling track, thereby better adapting to different pipeline laying design depths and different construction site conditions; the pipe dragging track is accurate, the precision is high, and the design requirement is met; during the whole construction process, the position and the burial depth of the pipeline can be determined on the ground at any time; adopt drill bit efflux to assist and creep into, specifically do: adopting high-pressure slurry jet flow erosion crushing rotary cutting of a drill bit to form a guide hole, and controlling the drilling direction by using a 15-degree inclined-plane drill bit; drilling at the soil-entering point, wherein the drill bit is driven by the drilling machine to rotate under the action of the thrust of the drilling machine and the pressure of slurry, and the soil layer is cut and the ruler is continuously advanced; if the rotation and the feeding are carried out simultaneously in the drilling process, the guided drilling is linear drilling; if the drill bit is fed without rotation, a curve section and a straight section of a drilling track can be formed under the action of the reaction force of a 15-degree inclined plane of the drill bit, the curve section is used as a part of drilling, the requirement of the working safety of a pipeline is met, the drilling design track is smooth, the curve section is smooth, the drill bit is suitable for underground pipeline traction crossing construction of underground pipelines of underground pipe networks distributed in complex sections, the success of pipeline construction is ensured, and the drill bit is also suitable for complex geological structures such as riprap, backfill and the like.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

A construction method for pulling and crossing buried pipelines mainly comprises the following steps:

s1, determining an earth entry point and an earth exit point according to a design drawing and actual investigation;

s2, designing according to the drilling track of the design drawing, and preparing a pipeline with the required length;

s3 drilling guide holes

Adopt drill bit efflux to assist and creep into, specifically do: adopting high-pressure slurry jet flow erosion crushing rotary cutting of a drill bit to form a guide hole, and controlling the drilling direction by using a 15-degree inclined-plane drill bit;

drilling at the soil-entering point, wherein the drill bit is driven by the drilling machine to rotate under the action of the thrust of the drilling machine and the pressure of slurry, and the soil layer is cut and the ruler is continuously advanced;

if the rotation and the feeding are carried out simultaneously in the drilling process, the guided drilling is linear drilling;

if the drill bit is fed and does not rotate, the deflecting drilling is implemented under the action of the 15-degree inclined plane reaction force of the drill bit, and the accurate position and state of the drill bit and the direction of the inclined plane drill bit are determined and determined according to a signal transmitter and a ground positioning tracer in a drill bit cavity;

measuring the drill bit once each drill rod is drilled, and directing an operator of the drilling machine to adjust drill bit parameters according to the measured parameters and adjust the drilling direction of the drill bit in time so as to control the drill bit to drill according to a designed track, ensure the finished pilot hole until the preset position of the drill bit is unearthed and finish the drilling work of the whole pilot hole;

s4, reaming

Combining a drill rod, a reamer, a transfer case and the drill rod into a pre-reaming drilling tool, jetting a soil layer by using high-pressure slurry to loosen the soil layer, extruding the soil layer to form a hole by using a conical drill bit of the reaming drilling tool under the action of rotation and tension, simultaneously jetting a large amount of slurry into a back reaming hole, conveying cut soil scraps to the ground to play a reaming role and forming a track hole;

the slurry is mixed with a lubricant, soda ash, a diamond thickener and a biopolymer;

s5, drawing through pipeline

After reaming, a reamer, a universal rotary joint and a U-shaped ring are installed by a hoisting machine in a matching way, the reamer with the diameter being 1.5 times of that of the pipeline is firmly connected with a steel pipe with the diameter being 1 time of that of the pipeline by a transfer case, and then the pipeline in the step S2 is dragged into the track hole formed in the step S4 under the matching of the hoisting machine and the rotary traction of the drilling machine until the pipeline is pulled to a pre-laying position at the side of the drilling machine;

and S6, welding and butting the traction pipeline with the pipelines at two sides after the traction pipeline is in place, and finishing pipeline traction.

In the method, in the traction crossing process, the accurate position and state of a drill bit and the direction of an inclined plane drill bit are determined and determined according to a signal transmitter in a drill bit cavity and a ground positioning tracer; measuring a drill bit once each drill rod is drilled, and directing an operator of the drilling machine to adjust drill bit parameters according to the measured parameters and adjust the drilling direction of the drill bit in time so as to control the drill bit to drill according to a designed track, ensure the finished guide hole and control the drilling track, thereby better adapting to different pipeline laying design depths and different construction site conditions; the pipe dragging track is accurate, the precision is high, and the design requirement is met; during the whole construction process, the position and the burial depth of the pipeline can be determined on the ground at any time; adopt drill bit efflux to assist and creep into, specifically do: adopting high-pressure slurry jet flow erosion crushing rotary cutting of a drill bit to form a guide hole, and controlling the drilling direction by using a 15-degree inclined-plane drill bit; drilling at the soil-entering point, wherein the drill bit is driven by the drilling machine to rotate under the action of the thrust of the drilling machine and the pressure of slurry, and the soil layer is cut and the ruler is continuously advanced; if the rotation and the feeding are carried out simultaneously in the drilling process, the guided drilling is linear drilling; if the drill bit is fed without rotation, a curve section and a straight section of a drilling track can be formed under the action of the reaction force of a 15-degree inclined plane of the drill bit, the curve section is used as a part of drilling, the requirement of the working safety of a pipeline is met, the drilling design track is smooth, the curve section is smooth, the drill bit is suitable for underground pipeline traction crossing construction of underground pipelines of underground pipe networks distributed in complex sections, the success of pipeline construction is ensured, and the drill bit is also suitable for complex geological structures such as riprap, backfill and the like.

The construction method has the advantages that traffic is not obstructed, the environment is not polluted, no damage is caused to the road surface and the river channel in the traction crossing construction process, the original soil structure is basically not damaged, underground water precaution and soft soil layer reinforcement measures are not needed, and the stress damage to the pipeline in the soil settling process is avoided.

The construction method greatly reduces the construction difficulty of laying the pipeline across the road or river, has high pipe laying speed and short construction period, is a pipeline with the same length and pipe diameter, has construction time of 1/2 of the construction time of a common jacking pipe, and ensures the construction period and the engineering quality.

In step S4, the high-pressure slurry is sprayed to the soil layer to loosen the soil layer, the conical drill bit extrudes the soil layer to form a hole under the action of rotation and tension, the hole wall of the formed hole is complete, compact and smooth, meanwhile, a large amount of slurry is injected into the return reaming hole to ensure the integrity of the return reaming hole, the cutting soil chips are carried back to the ground without collapse, and the hole-expanding effect is achieved; in addition, the slurry sprayed by the high-pressure slurry is mixed with pollution-free natural clay fine powder as a lubricant, so that the wall of a pore channel can be stabilized and has a lubricating effect, the friction force during pipe pulling is reduced to the minimum, and the slurry forms a circle of dry clay-coated pipeline in the future; in addition, in order to improve the performance of the slurry, soda ash is added into the slurry, the slurry can be tackified and the static shearing force can be increased, the diamond thickener can increase the lubrication in the hole and has good pore-forming performance, the biopolymer can improve the soil chip carrying capacity of the slurry, the soil chips in the hole are taken out, the slurry forms a mud skin on the wall of the hole, the seepage inside and outside the hole is isolated, the slurry leakage is avoided, the rotation torque and the pull-back force during pipe dragging are reduced, the friction coefficient of the steel pipe and the wall of the hole is reduced, and the lubricating effect is; the sprayed slurry can be used for hydraulic cutting, cooling the drill bit, reducing torque and guiding thrust during guiding and playing a guiding auxiliary role; the effect of the back expansion torque and the pulling force is reduced during back expansion; in order to ensure the smooth operation of the crossing engineering, the success of the crossing of the pipeline can be ensured only by practically ensuring the performance of the slurry.

When the hole expanding is performed in step S4, two pre-hole expanding operations are performed for the steel pipe having the outer diameter Φ 426mm laid:

reaming for the first time: connecting a phi 300mm reamer to the rear end of a drilling machine, then rotationally pulling back the reamer by the drilling machine for reaming, unloading one drill rod on one side of an earth entering point after each drill rod is reamed, installing one drill on one side of an earth discharging point, and repeating the steps until the phi 300mm reamer is reamed; injecting slurry while reaming;

and (5) reaming for the second time: and (3) unloading the phi 300mm reamer, replacing the phi 600mm reamer for back expansion, and simultaneously injecting slurry to ensure the reaming effect and the reaming integrity.

In the drilling process of the drilling machine in the steps S4 and S5, if the drilling is stopped, a proper amount of slurry is still injected, so that positive pressure is always present in the hole, the cuttings in the hole are conveyed out, and the cuttings are prevented from being deposited in the hole.

The mud is mainly bentonite, the lubricant agent mixed in the mud adopts natural clay fine powder, high-quality bentonite is used, the natural clay fine powder is stirred by a stirring system to form mud, the mud is injected into a hole, the mud is a key factor of guiding drilling, the mud can remove drilling soil cuttings, can suspend and carry the drilling soil cuttings to the ground surface, reduces corrosion, stabilizes and protects the hole wall, balances formation pressure, and plays a role in fixing the hole and protecting the pipe.

After the soil entry point and the soil exit point are determined in the step S1, the elevation and the horizontal distance of the soil entry point and the soil exit point of the construction site are retested, a whole position instrument is used for traversing the horizontal length position on the ground surface of the central line after being corrected according to the length and the inclination of each section of drill rod, and red paint sprayed mark piles are respectively arranged on the soil entry point and the soil exit point, and the elevation is measured pile by pile; after the elevation is measured pile by pile, discharging side line piles of a drilling working area, an approach road, a working pit of a pipeline soil-entering point and a drilling machine installation position, and spraying a gray line as an obvious range mark; and (3) discharging side line piles at one end of the unearthed point according to the central line of the pipeline, the occupied area width and the length of the pipeline, the length and the width of a working pit of the unearthed point of the pipeline and the length and the width of the discharge ditch, then spreading white ash along the edge to form a side line, marking an unearthed point operation area, completing measurement preparation work before construction, accurately finding an unearthed point and an unearthed point, and facilitating accurate construction.

In step S2, a reinforcing rib is welded to the pipe according to the diameter of the pipe opening to perform a stabilizing and reinforcing function.

Before the drilling in the step S3 is carried out, a working pit is excavated at the soil outlet and the soil inlet by a machine for placing slurry, so that the environmental pollution is avoided.

And before the step S3 of drilling, performing trial injection on the slurry of the drilling machine, and drilling 2-3 sections of drill rods by the drilling machine in a trial manner to ensure the normal work of the drilling machine.

And after the butt welding is finished in the step S6, performing nondestructive testing and anticorrosion and heat preservation treatment to ensure the quality of the pipeline.

The construction method is implemented by combining the centralized heating and capacity expansion of the Lijin county and city district as follows:

taking the second standard section of the construction of the centralized heating capacity expansion reconstruction project in the Rijin county district as an example, in the project, the DN800 pipeline needs to cross three main roads in the county city in total, the construction is carried out by adopting the traditional excavation mode, the cost is about 63 ten thousand yuan from the road surface excavation to the road surface recovery, the directional drilling traction crossing construction is adopted, the equipment lease cost is only 60 ten thousand yuan, the cost is saved by 3 ten thousand yuan, the construction time is shortened by about 9 days compared with the excavation, and the purposes of saving time, labor and money are achieved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.