阅读说明：本技术 连续侧限约束土体滑移的道路路基加固方法 (Road subgrade strengthening method for continuously limiting and restraining soil body slippage ) 是由 王天野 张志敏 蒋新建 谭志斌 于 2020-06-12 设计创作，主要内容包括：本发明涉及一种连续侧限约束土体滑移的道路路基加固方法,步骤一：拉筋加工；拉筋采用热轧带肋钢筋加工,螺栓套筒连接接长,敷设时拉筋前端设有工具式冲击头；步骤二：冲击敷设拉筋；拉筋水平间距宜按4~6m或根据拉筋张拉紧固与侧限墙联合可抵抗路基土的侧向压力计算确定；步骤三：侧限墙施工；高填方路基侧限墙根据拉筋道数设置,路基按一道拉筋加固时按常规设置即可,两道以上拉筋可分层设置,也可整幅设置；步骤四：拉筋张拉紧固；穿墙拉筋张拉前需清除锚固段防水涂料；步骤五：工作井砌筑。本发明将拉筋设置在土路基中,通过施加紧固力,使路基土受到横向约束,有效阻止深层路基土受到剪切破坏产生侧向滑移,明显提高了道路承载能力。(The invention relates to a road subgrade strengthening method for continuously restraining soil slippage in a lateral limit manner, which comprises the following steps: stretching ribs; the lacing wire is processed by hot rolling ribbed steel bars, the bolt sleeve is connected and lengthened, and the front end of the lacing wire is provided with a tool type impact head during laying; step two: impacting and laying a lacing wire; the horizontal spacing of the tie bars is preferably calculated and determined according to 4-6 m or the lateral pressure of the roadbed soil which can be resisted by the combination of the tie bars tensioned and fastened and the side limiting walls; step three: constructing a side limiting wall; the side limiting walls of the high fill roadbed are arranged according to the number of the tie bars, the roadbed can be reinforced according to one tie bar and can be arranged conventionally, and the two or more tie bars can be arranged in layers or in a whole frame; step four: tensioning and fastening the lacing wire; removing the waterproof paint of the anchoring section before tensioning the through-wall lacing wire; step five: and (5) building the working well. The invention arranges the tie bars in the soil subgrade, and applies fastening force to make the subgrade soil be transversely restrained, thereby effectively preventing the deep subgrade soil from being sheared and damaged to generate lateral slippage and obviously improving the bearing capacity of the road.)

1. A road subgrade strengthening method for continuously restraining soil slippage by lateral limitation is characterized by comprising the following steps:

the method comprises the following steps: lacing wire processing

The lacing wire is processed by hot rolling ribbed steel bars, the bolt sleeve is connected and lengthened, and the front end of the lacing wire is provided with a tool type impact head during laying;

and (3) a lacing wire processing flow:

removing rust of the lacing wire one by one → processing threads on two ends → painting Polyurethane (PU) waterproof paint → connecting and lengthening the lacing wire by a bolt sleeve → painting the Polyurethane (PU) waterproof paint on the lacing wire joint and the bolt sleeve → coating the lacing wire with a plastic tie for protecting the waterproof paint;

step two: impact laying lacing wire

The horizontal spacing of the tie bars is preferably calculated and determined according to 4-6 m or the lateral pressure of the roadbed soil which can be resisted by the combination of the tie bars tensioned and fastened and the side limiting walls;

the processed tie bars are laid by adopting an impact method, the positions of roadbed structures where the tie bars are laid by impact are divided into two conditions, one is a high fill roadbed with a roadbed structure layer higher than the ground, the other is a common roadbed with a roadbed structure layer lower than the ground, the tie bars are laid on the high fill roadbed, the operation platform is erected on one side of the roadbed by using scaffold steel pipes according to the preset laying positions, and the operation platform is operated on the erected operation platform by impacting the laid tie bars; laying a tie bar on a common roadbed, excavating a groove on one side of the roadbed, and impacting and laying the tie bar in the excavated groove;

the method comprises the following steps that a high fill roadbed impact laying lacing wire operation platform structure is erected, a guide steel pipe with the diameter of 75mm and the length of about 1.0m is required to be arranged at the front end of a lacing wire entering the soil to assist the lacing wire to be laid according to a preset path, a movable lacing wire support rod is required to be arranged on the operation platform, and a lacing wire guide ring is arranged on the support rod;

the method comprises the following steps that (1) a common roadbed impact laying tie bar groove is excavated, a guide steel pipe with the diameter of 75mm and the length of about 1.0m is also required to be arranged at the front end of the tie bar, which is used for assisting the laying of the tie bar according to a preset path, a movable tie bar support rod is also required to be arranged in the groove, and a tie bar guide ring is arranged on the support rod;

the high fill subgrade is provided with retaining walls in a layered mode, bottom retaining wall construction is firstly carried out, after the tie bars are impacted and stretched, the upper retaining wall construction and the tie bar impact laying and stretching are carried out;

a tool type impact cap, wherein a steel pipe with the diameter of 10-15 mm larger than the tie bar is 60-80 mm long, one end of the steel pipe is welded on a steel plate with the thickness of about 20mm, and the other side of the steel plate is welded with a drill rod of an air pick; when the tie bar is laid in an impacting way, the steel chisel of the impact cap is arranged on the pneumatic pick gun;

the lacing wire is impacted and laid, the first section of lacing wire passes through the guide ring and the guide steel pipe, the head part is provided with a tool type impact head, the tail part is provided with a straight thread sleeve, then the short steel bar which is made of the same material as the lacing wire and is provided with a coarse thread and an external thread with the length of about 150mm is arranged at the end part to be used as the impact head for impacting and laying the lacing wire, the pneumatic pick provided with the tool type impact cap is adopted to impact the lacing wire impact head when the lacing wire is laid, and the lacing wire is impacted and laid by repeated circulation operation according to the method of section-by-section impact, extension and re; when the lacing wire is impacted to lay, when an impact head approaches to the guide ring, the guide ring and the bracket steel pipe are detached one by one, the steel pipe approaches to the guide ring by about 30mm, the impact operation is stopped, the lacing wire is lengthened, the impact operation is continued until the lacing wire penetrates through the roadbed structural layer, and the exposed length of the lacing wire meets the preset requirement;

the construction of the side limiting wall and the backfilling of the inner side groove need to arrange the exposed tie bar through the wall, and the exposed thread needs to be properly protected;

step three: construction of side wall

The side limiting walls of the high fill roadbed are arranged according to the number of the tie bars, the roadbed can be reinforced according to one tie bar and can be arranged conventionally, and the two or more tie bars can be arranged in layers or in a whole frame;

step four: stretching and fastening of lacing wire

Removing the waterproof paint of the anchoring section before tensioning the through-wall lacing wire;

4.1 tensioning device

The tension and fastening of the lacing wire are preferably realized by adopting a hydraulic piercing jack with the tension of more than 30 tons, and the working capacity of the jack is determined according to the axial tensile strength value of the lacing wire;

4.2 tensioning sequence

Tensioning is sequentially carried out from one end of the side limiting wall to the other end, the roadbed of the whole side limiting wall is arranged, and an upper lacing wire and a lower lacing wire which are positioned at the same horizontal position are simultaneously tensioned;

4.3 applying load by tension

Tensioning and applying loads in a grading manner, applying the loads in a first stage according to 0.1-0.2 times of the design value of the axial tension of the lacing wire, and observing displacement for 2 min; applying the second stage according to 0.5-0.7 times of the design value of the axial tension of the lacing wire, and observing the displacement for 5 min; and applying the third stage according to 1.05-1.10 times of the design value of the axial tension of the lacing wire, observing the displacement for 15min, unloading to lock load and locking, determining the design value of the axial tension of the lacing wire as the lock load, and determining the design value of the axial tension according to the following formula:

Nt=(As×fyk)/Kt

in the formula: nt-design value of axial tension (KN) of lacing wire;

as-lacing cross-sectional area (mm 2);

kt is the tensile safety coefficient of the lacing wire, and is 1.6;

Fyk-Standard value of tensile Strength of lacing wire (N/mm 2);

4.4 Anchor head Reserve

After the lacing wire is tensioned, the reserved length of the tensioning head is not less than 1.0m so as to meet the requirement that the lacing wire can be compensated and tensioned in the using process of the roadbed, and effective rust prevention measures such as coating grease, wrapping and sealing are adopted for the reserved exposed lacing wire;

step five: working well masonry

The high fill roadbed reinforcement does not need to be provided with a working well, and the common roadbed reinforcement needs to be provided with a whole side limiting wall and a working well. After the lacing wire tensioning and fastening are finished, a 1.0m multiplied by 1.2m working well is built by shale sintered bricks at the lacing wire fastening position on the outer side of the whole side limiting wall, so that operations such as maintenance of a reserved head, lacing wire compensation and fastening tensioning and the like in the using process are facilitated, waterproof cement mortar with the thickness of 10mm is smeared in and out the well wall, a ladder stand is arranged in the working well, a worker can conveniently go in and out for overhauling, a reinforced concrete cover plate is arranged at the well mouth, a phi 710 cast iron well cover is covered, and a foundation pit on the outer side of the side limiting wall is filled and rolled in a layered mode.

2. The method for strengthening the roadbed of the road with the continuous lateral confinement constraint on soil body slippage, according to claim 1, wherein the method comprises the following steps: in the first step, a mechanical method is adopted for removing rust before the lacing wire is processed, and the surface is required to be smooth and free of floating rust;

and after rust removal, external threads are machined at two ends according to the thick teeth, lacing wire threads are machined according to the required length, the length of the external threads of the start end head and the tail end head is 100mm, and the length of the threads of other end heads is 50 mm.

After the ribs are machined with threads, the threads are wrapped by using an adhesive tape and coated with Polyurethane (PU) waterproof paint in time, the Polyurethane (PU) waterproof paint is coated for multiple times, and the total thickness of the coating is more than 1 mm;

the tool type impact head is processed by adopting a steel bar with the diameter larger than 40mm of the lacing wire, the steel bar with the length of 100mm is taken, one end of the steel bar with the length of about 50mm is milled and processed into a cone, the other end of the steel bar is processed into an internal thread matched with the external thread of the lacing wire according to thick teeth, the length of the thread is about 50mm, and a guide steel plate with the thickness of 2mm is symmetrically welded on the four sides of the outer side.

3. The method for strengthening the roadbed of the road with the continuous lateral confinement constraint on soil body slippage, according to claim 1, wherein the method comprises the following steps: in the third step, the construction of the side wall is carried out in an inverted T shape according to the structural form of the cast-in-place reinforced concrete retaining wall, the thickness of the wall and the base is preferably 0.3-0.5 m, the height of the wall and the width of the bottom plate are determined according to the site working condition, the strength of the reinforcing steel bars and the concrete is the same as the requirement of the conventional retaining wall, the steel base plate and the steel sleeve are embedded in the position where the reinforcing steel bars penetrate through the wall, and the reinforcing steel bars are reinforced within the range of 1.0m multiplied by 1.0 m; the steel backing plate is processed by adopting a steel plate with the thickness of 30mm and the thickness of 0.6m multiplied by 0.6m, and a reinforcing steel bar fluke is arranged; the steel sleeve is processed by adopting a seamless steel pipe with the diameter of more than phi 60 or the corresponding diameter, the seamless steel pipe is welded with the steel backing plate in a T shape, and the diameter of the steel sleeve of the side limiting wall at the initial position of the impact laying lacing wire is preferably increased until an impact head smoothly passes through the steel sleeve; and setting settlement separation joints at intervals of 30m on the side limiting walls, maintaining the side limiting walls in time after the pouring construction of the side limiting walls is finished, and filling and tamping foundation pits on the inner sides of the walls in layers at proper time.

Technical Field

The invention relates to the field of road bed construction, in particular to a road bed reinforcing method for continuously restricting soil body slippage by lateral limitation.

Background

In the existing road foundation construction, the method of layered filling and rolling is mainly adopted. The construction is limited by the construction period, the construction time of the roadbed and the underground pipelines is short, the pre-pressing settlement time is short after the roadbed or the grooves are filled, even the pre-pressing is not carried out, the construction of a road base layer and a surface layer is carried out, the settlement and the roadbed structure damage of different degrees appear in the use process of the road after the completion and the traffic is completed, irregular cracks appear on the road surface, longitudinal reflection cracks appear on the road surface seriously, even the underground pipelines are damaged, and the potential safety hazard is buried for the road passage. This is usually the case in high fill subgrades and sandy subgrades, mainly because the lower soil mass is compressed and damaged by transverse shearing after the completion of the road and the completion of the vehicle under the action of dynamic load. In addition, uneven settlement of the filled subgrade is also a cause of the above-mentioned damage.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a road subgrade strengthening method for continuously restricting soil body slippage by lateral limitation, so that the overall bearing capacity of the subgrade is improved, the uneven settlement of the subgrade is controlled, and the occurrence of diseases such as lateral slippage of soil bodies in deep layers of the subgrade is effectively prevented.

In order to solve the technical problem, the invention is realized as follows:

a road subgrade strengthening method for continuously restraining soil slippage by lateral limitation is characterized by comprising the following steps:

the method comprises the following steps: lacing wire processing

The lacing wire is processed by hot rolling ribbed steel bars, the bolt sleeve is connected and lengthened, and the front end of the lacing wire is provided with a tool type impact head during laying;

and (3) a lacing wire processing flow:

removing rust of the lacing wire one by one → processing threads on two ends → painting Polyurethane (PU) waterproof paint → connecting and lengthening the lacing wire by a bolt sleeve → painting the Polyurethane (PU) waterproof paint on the lacing wire joint and the bolt sleeve → coating the lacing wire with a plastic tie for protecting the waterproof paint;

step two: impact laying lacing wire

The horizontal spacing of the tie bars is preferably calculated and determined according to 4-6 m or the lateral pressure of the roadbed soil which can be resisted by the combination of the tie bars tensioned and fastened and the side limiting walls;

the processed tie bars are laid by adopting an impact method, the positions of roadbed structures where the tie bars are laid by impact are divided into two conditions, one is a high fill roadbed with a roadbed structure layer higher than the ground, the other is a common roadbed with a roadbed structure layer lower than the ground, the tie bars are laid on the high fill roadbed, the operation platform is erected on one side of the roadbed by using scaffold steel pipes according to the preset laying positions, and the operation platform is operated on the erected operation platform by impacting the laid tie bars; laying a tie bar on a common roadbed, excavating a groove on one side of the roadbed, and impacting and laying the tie bar in the excavated groove;

the method comprises the following steps that a high fill roadbed impact laying lacing wire operation platform structure is erected, a guide steel pipe with the diameter of 75mm and the length of about 1.0m is required to be arranged at the front end of a lacing wire entering the soil to assist the lacing wire to be laid according to a preset path, a movable lacing wire support rod is required to be arranged on the operation platform, and a lacing wire guide ring is arranged on the support rod;

the method comprises the following steps that (1) a common roadbed impact laying tie bar groove is excavated, a guide steel pipe with the diameter of 75mm and the length of about 1.0m is also required to be arranged at the front end of the tie bar, which is used for assisting the laying of the tie bar according to a preset path, a movable tie bar support rod is also required to be arranged in the groove, and a tie bar guide ring is arranged on the support rod;

the high fill subgrade is provided with retaining walls in a layered mode, bottom retaining wall construction is firstly carried out, after the tie bars are impacted and stretched, the upper retaining wall construction and the tie bar impact laying and stretching are carried out;

a tool type impact cap, wherein a steel pipe with the diameter of 10-15 mm larger than the tie bar is 60-80 mm long, one end of the steel pipe is welded on a steel plate with the thickness of about 20mm, and the other side of the steel plate is welded with a drill rod of an air pick; when the tie bar is laid in an impacting way, the steel chisel of the impact cap is arranged on the pneumatic pick gun;

the lacing wire is impacted and laid, the first section of lacing wire passes through the guide ring and the guide steel pipe, the head part is provided with a tool type impact head, the tail part is provided with a straight thread sleeve, then the short steel bar which is made of the same material as the lacing wire and is provided with a coarse thread and an external thread with the length of about 150mm is arranged at the end part to be used as the impact head for impacting and laying the lacing wire, the pneumatic pick provided with the tool type impact cap is adopted to impact the lacing wire impact head when the lacing wire is laid, and the lacing wire is impacted and laid by repeated circulation operation according to the method of section-by-section impact, extension and re; when the lacing wire is impacted to lay, when an impact head approaches to the guide ring, the guide ring and the bracket steel pipe are detached one by one, the steel pipe approaches to the guide ring by about 30mm, the impact operation is stopped, the lacing wire is lengthened, the impact operation is continued until the lacing wire penetrates through the roadbed structural layer, and the exposed length of the lacing wire meets the preset requirement;

the construction of the side limiting wall and the backfilling of the inner side groove need to arrange the exposed tie bar through the wall, and the exposed thread needs to be properly protected;

step three: construction of side wall

The side limiting walls of the high fill roadbed are arranged according to the number of the tie bars, the roadbed can be reinforced according to one tie bar and can be arranged conventionally, and the two or more tie bars can be arranged in layers or in a whole frame;

step four: stretching and fastening of lacing wire

Removing the waterproof paint of the anchoring section before tensioning the through-wall lacing wire;

4.1 tensioning device

The tension and fastening of the lacing wire are preferably realized by adopting a hydraulic piercing jack with the tension of more than 30 tons, and the working capacity of the jack is determined according to the axial tensile strength value of the lacing wire;

4.2 tensioning sequence

Tensioning is sequentially carried out from one end of the side limiting wall to the other end, the roadbed of the whole side limiting wall is arranged, and an upper lacing wire and a lower lacing wire which are positioned at the same horizontal position are simultaneously tensioned;

4.3 applying load by tension

Tensioning and applying loads in a grading manner, applying the loads in a first stage according to 0.1-0.2 times of the design value of the axial tension of the lacing wire, and observing displacement for 2 min; applying the second stage according to 0.5-0.7 times of the design value of the axial tension of the lacing wire, and observing the displacement for 5 min; and applying the third stage according to 1.05-1.10 times of the design value of the axial tension of the lacing wire, observing the displacement for 15min, unloading to lock load and locking, determining the design value of the axial tension of the lacing wire as the lock load, and determining the design value of the axial tension according to the following formula:

Nt=(As×fyk)/Kt

in the formula: nt-design value of axial tension (KN) of lacing wire;

as-lacing cross-sectional area (mm 2);

kt is the tensile safety coefficient of the lacing wire, and is 1.6;

Fyk-Standard value of tensile Strength of lacing wire (N/mm 2);

4.4 Anchor head Reserve

After the lacing wire is tensioned, the reserved length of the tensioning head is not less than 1.0m so as to meet the requirement that the lacing wire can be compensated and tensioned in the using process of the roadbed, and effective rust prevention measures such as coating grease, wrapping and sealing are adopted for the reserved exposed lacing wire;

step five: working well masonry

The high fill roadbed reinforcement does not need to be provided with a working well, and the common roadbed reinforcement needs to be provided with a whole side limiting wall and a working well. After the lacing wire tensioning and fastening are finished, a 1.0m multiplied by 1.2m working well is built by shale sintered bricks at the lacing wire fastening position on the outer side of the whole side limiting wall, so that operations such as maintenance of a reserved head, lacing wire compensation and fastening tensioning and the like in the using process are facilitated, waterproof cement mortar with the thickness of 10mm is smeared in and out the well wall, a ladder stand is arranged in the working well, a worker can conveniently go in and out for overhauling, a reinforced concrete cover plate is arranged at the well mouth, a phi 710 cast iron well cover is covered, and a foundation pit on the outer side of the side limiting wall is filled and rolled in a layered mode.

The road subgrade strengthening method for continuously restricting soil body slippage by lateral confinement is characterized in that: in the first step, a mechanical method is adopted for removing rust before the lacing wire is processed, and the surface is required to be smooth and free of floating rust;

and after rust removal, external threads are machined at two ends according to the thick teeth, lacing wire threads are machined according to the required length, the length of the external threads of the start end head and the tail end head is 100mm, and the length of the threads of other end heads is 50 mm.

After the ribs are machined with threads, the threads are wrapped by using an adhesive tape and coated with Polyurethane (PU) waterproof paint in time, the Polyurethane (PU) waterproof paint is coated for multiple times, and the total thickness of the coating is more than 1 mm;

the tool type impact head is processed by adopting a steel bar with the diameter larger than 40mm of the lacing wire, the steel bar with the length of 100mm is taken, one end of the steel bar with the length of about 50mm is milled and processed into a cone, the other end of the steel bar is processed into an internal thread matched with the external thread of the lacing wire according to thick teeth, the length of the thread is about 50mm, and guide steel plates with the thickness of 2mm are symmetrically welded on the four sides of the outer side of;

the road subgrade strengthening method for continuously restricting soil body slippage by lateral confinement is characterized in that: in the third step, the construction of the side wall is carried out in an inverted T shape according to the structural form of the cast-in-place reinforced concrete retaining wall, the thickness of the wall and the base is preferably 0.3-0.5 m, the height of the wall and the width of the bottom plate are determined according to the site working condition, the strength of the reinforcing steel bars and the concrete is the same as the requirement of the conventional retaining wall, the steel base plate and the steel sleeve are embedded in the position where the reinforcing steel bars penetrate through the wall, and the reinforcing steel bars are reinforced within the range of 1.0m multiplied by 1.0 m; the steel backing plate is processed by adopting a steel plate with the thickness of 30mm and the thickness of 0.6m multiplied by 0.6m, and a reinforcing steel bar fluke is arranged; the steel sleeve is processed by adopting a seamless steel pipe with the diameter of more than phi 60 or the corresponding diameter, the seamless steel pipe is welded with the steel backing plate in a T shape, and the diameter of the steel sleeve of the side limiting wall at the initial position of the impact laying lacing wire is preferably increased until an impact head smoothly passes through the steel sleeve; and setting settlement separation joints at intervals of 30m on the side limiting walls, maintaining the side limiting walls in time after the pouring construction of the side limiting walls is finished, and filling and tamping foundation pits on the inner sides of the walls in layers at proper time.

The invention has the beneficial effects that: the reinforcing effect is better, and the road bed is more firm to in the road use, under the condition of not excavating the road, can compensate the reinforcement to the road bed. The integral bearing capacity of the roadbed is improved, the uneven settlement of the roadbed is controlled, and the occurrence of diseases such as lateral sliding of a deep soil body of the roadbed and the like is effectively prevented.

Drawings

The invention is described in further detail below with reference to the following figures and embodiments:

FIG. 1 is a schematic view of the tendon processing and corrosion prevention at the beginning and end sections.

Fig. 2 is a schematic view of common section lacing wire processing and corrosion prevention.

Fig. 3 is a schematic view of an impact tool head.

Fig. 4 is a schematic diagram of the impact laying tie bars of the high fill subgrade.

Fig. 5 is a schematic diagram of a common roadbed impact laying tie bar.

Fig. 6 is a schematic view at a in fig. 4 and 5.

Fig. 7 is a schematic view at B in fig. 4 and 5.

Fig. 8 is a schematic view at C in fig. 4 and 5.

Fig. 9 is a schematic view at 2-2 in fig. 5.

Fig. 10 is a schematic view at 3-3 of fig. 5.

Fig. 11 is a schematic diagram of a conventional roadbed working well.

Fig. 12 is a schematic view at D in fig. 11.

Detailed Description

As shown in fig. 1: a road subgrade strengthening method for continuously restricting soil body slippage by lateral limitation comprises the following steps:

the method comprises the following steps: lacing wire processing

The lacing wire is processed by hot rolling ribbed steel bar with diameter of more than 28 (or according to requirements), the bolt sleeve is connected and lengthened, and the front end of the lacing wire is provided with a tool type impact head when being laid.

And (3) a lacing wire processing flow:

removing rust of the lacing wire one by one → processing threads on two ends → painting Polyurethane (PU) waterproof paint → connecting and lengthening the lacing wire by a bolt sleeve → painting the Polyurethane (PU) waterproof paint on the lacing wire joint and the bolt sleeve → coating the lacing wire with a plastic tie for protecting the waterproof paint.

The tie bar raw material and the joint are required to be subjected to mechanical property tests according to relevant regulations of steel bar detection tests, and can be used after being qualified.

The mechanical method is adopted for removing rust before the lacing wire processing, and the surface is required to be smooth and have no floating rust.

And after rust removal, processing external threads 1 at two ends according to coarse teeth, processing the lacing wire threads according to the required length, wherein the lengths of the external threads at the start end and the tail end are both 100mm, and the lengths of the threads at other ends are 50 mm.

And after the thread is processed by the lacing wire, the thread is wrapped by an adhesive tape and the Polyurethane (PU) waterproof paint 2 is coated in time. The Polyurethane (PU) waterproof paint is applied in multiple coats, and the total thickness of the coating is more than 1 mm.

The lacing wire is lengthened by adopting a galvanized thick-tooth straight thread steel bar connecting sleeve. The sleeve used for connecting the lacing wires is preferably a commodity sleeve, and the external threads processed by the lacing wires must be matched with the internal threads of the sleeve. And before laying the lacing wire, a plastic binding belt 3 is wrapped outside the lacing wire to protect the waterproof coating of the lacing wire. See the attached figures 1 and 2 for details.

The tool type impact head 12 is processed by steel bars with the diameter larger than that of the lacing wire by 40 mm. A steel bar with the length of 100mm is taken, one end of the steel bar is milled and processed into a cone with the length of about 50mm, the other end of the steel bar is processed into an internal thread 5 matched with the external thread of the lacing wire according to thick teeth, the length of the thread is about 50mm, and a guide steel plate 4 with the thickness of 2mm is symmetrically welded on the four sides of the outer side of the steel bar. See figure 3 for details.

Step two: impact laying lacing wire

The horizontal spacing of the tie bars is preferably determined according to 4-6 m or calculated according to the lateral pressure of the roadbed soil which can be resisted by the combination of the tie bar tensioning and fastening and the side limiting wall.

The processed lacing wire is laid by adopting an impact method. The roadbed structure with the impact laid tie bars is located in two conditions, namely a high fill roadbed with a roadbed structure layer higher than the ground (figure 4), and a common roadbed with a roadbed structure layer lower than the ground (figure 5). The technical scheme is that the tie bars are laid on the high-fill roadbed, the side limiting walls are arranged in layers for illustration, the tie bars are arranged on one side of the roadbed by using scaffold steel pipes to set up an operation platform 6 according to a preset laying position, impact laying tie bars are operated on the set operation platform, one side retaining wall 9 is constructed after impact laying tie bars are laid, the other side retaining wall 10 can be constructed before impact laying tie bars or after impact laying tie bars are laid, a lower retaining wall is constructed first, and an upper retaining wall is constructed after impact tensioning of tie bars; and laying a tie bar on the common roadbed, excavating a groove 7 on one side of the roadbed, and impacting the laid tie bar to implement in the excavated groove. See figures 4 and 5 for details.

The high fill subgrade impact laying lacing wire operation platform is erected according to the structure shown in the attached figure 4, and particularly, a guide steel pipe with the diameter of 75mm and the length of about 1.0m is required to be arranged at the front end of the lacing wire, which is used for assisting the lacing wire to be laid according to a preset path 8. In addition, the operating platform is also required to be provided with a movable lacing wire support rod, and the support rod is provided with a lacing wire guide ring. See fig. 6 and 7 for details.

The common roadbed impact laying tie bar groove is excavated according to the attached drawings 5, 9 and 10, and it is specially described that a guide steel pipe 11 with the diameter of 75mm and the length of about 1.0m is also required to be arranged at the front end of the tie bar in the soil to assist the tie bar 14 to be laid according to a preset path. In addition, a movable lacing wire support rod 13 is also arranged in the groove, and a lacing wire guide ring 15 is arranged on the support rod. See fig. 6 and 7 for details.

The retaining walls are arranged on the high fill subgrade in a layered mode, bottom retaining wall construction is firstly carried out, after the tie bars are impacted and stretched, the retaining wall construction and the tie bar impact laying and stretching are carried out on the upper retaining wall.

A tool type impact cap is characterized in that a steel pipe with the diameter being 10-15 mm larger than that of a lacing bar 14 is 60-80 mm long, one end of the steel pipe is welded on a steel plate with the thickness being about 20mm, and the other side of the steel plate is welded with a pneumatic pick steel chisel 16. When the tie bar is laid in an impacting mode, the steel chisel of the impact cap is installed on the pneumatic pick gun. See in detail the schematic diagram of fig. 8.

And (3) performing impact laying on the lacing wires, enabling the first section of lacing wires to pass through the guide ring 15 and the guide steel pipe 17, installing a tool type impact head at the head, installing a straight thread sleeve at the tail, then installing short steel bars which are made of the same material as the lacing wires, machining the thick thread with the length of about 150mm at the end parts, using the short steel bars as the impact heads for impacting the laid lacing wires, adopting an air pick with an additional tool type impact cap to impact the lacing wire impact head during laying of the lacing wires, and completing the impact laying of the lacing wires through repeated circulation operation according to a method of section-by-section impact, lengthening and re-impact. When the lacing wire strikes and lays operation, when the impact head is close to the guide ring, the guide ring and the bracket steel pipe 18 are detached one by one, the guide ring and the bracket steel pipe are close to the guide steel pipe by about 30mm, the impact operation is stopped, the lacing wire is lengthened, the impact operation is continued until the lacing wire penetrates through the roadbed structure layer, and the exposed length of the lacing wire meets the preset requirement.

The construction of the side limiting wall and the backfilling of the inner side groove need to arrange the exposed tie bar through the wall, and the exposed screw thread needs to be properly protected.

Step three: construction of side wall

The side limiting walls of the high fill roadbed are arranged according to the number of the tie bars, the roadbed can be arranged according to the conventional method when being reinforced by one tie bar, and the tie bars above two can be arranged in layers or in a whole frame. The technical scheme takes the example of arranging side limiting walls in layers as an illustration; the side limit strength of the common roadbed is suitable to be arranged in a whole frame.

The construction of the side limiting wall 27 is in an inverted T-shaped arrangement according to the structural form of the cast-in-place reinforced concrete retaining wall. The thickness of the wall body and the base is preferably 0.3-0.5 m, and the height of the wall body and the width of the bottom plate are determined according to the field working condition. The reinforcement and concrete strength are the same as the requirements of the conventional retaining wall. The steel backing plate and the steel sleeve 23 are embedded at the position where the tie bars penetrate the wall, and the reinforcing bars are reinforced within the range of 1.0m multiplied by 1.0 m. The steel backing plate is processed by adopting a steel plate with the thickness of 30mm and the thickness of 0.6m multiplied by 0.6m, and a reinforcing steel bar fluke is arranged; the steel sleeve is processed by a seamless steel pipe with the diameter of more than 60 mm or the corresponding diameter, and is welded with the steel backing plate in a T shape. The diameter of the steel sleeve of the side limiting wall at the initial position of the impact laying lacing wire is preferably increased until the impact head smoothly passes through the steel sleeve. The clamping piece 24, the anchorage device 25 and the anchor backing plate 26 are sequentially arranged outside the other end of the lacing wire 14 penetrating the wall for fixing, and the detailed view is shown in the schematic diagram of fig. 12. The side limiting walls are provided with settlement separating seams at intervals of 30 m. And (5) timely maintaining the side limiting wall after the pouring construction is finished, and timely filling and tamping the foundation pit on the inner side of the wall in layers.

Step four: stretching and fastening of lacing wire

Before the wall-through lacing wire is tensioned, the waterproof coating of the anchoring section needs to be removed.

4.1 tensioning device

The tension and fastening of the lacing wire are preferably realized by adopting a hydraulic penetrating jack with the tension force of more than 30 tons, and the working capacity of the jack is determined according to the axial tensile strength value of the lacing wire.

4.2 tensioning sequence

Tensioning is performed from one end of the side limiting wall to the other end of the side limiting wall in sequence. And (4) setting the roadbed of the whole side limiting wall, and simultaneously tensioning the upper and lower lacing wires at the same horizontal position.

4.3 applying load by tension

Tensioning and applying loads in a grading manner, applying the loads in a first stage according to 0.1-0.2 times of the design value of the axial tension of the lacing wire, and observing displacement for 2 min; applying the second stage according to 0.5-0.7 times of the design value of the axial tension of the lacing wire, and observing the displacement for 5 min; and the third stage is applied according to 1.05-1.10 times of the design value of the axial tension of the lacing wire, and the displacement observation is carried out for 15 min. And then unloaded to a locked load and locked. And determining the design value of the axial tension of the lacing wire as the locking load. The axial tension design value is determined according to the following formula:

Nt=(As×fyk)/Kt

in the formula: nt-design value of axial tension (KN) of lacing wire;

as-lacing cross-sectional area (mm 2);

kt is the tensile safety coefficient of the lacing wire, and is 1.6;

Fyk-Standard value of tensile Strength of lacing wire (N/mm 2).

4.4 Anchor head Reserve

After the lacing wire is tensioned, the reserved length of the tensioning head is not less than 1.0m so as to meet the requirement that the lacing wire can be compensated and tensioned in the use process of the roadbed. The reserved exposed lacing wire adopts effective rust prevention measures such as coating grease, packaging and sealing.

Step five: working well masonry

The high fill roadbed reinforcement does not need to be provided with a working well, the common roadbed 20 reinforcement needs to be provided with a whole side limiting wall and a working well, the roadbed is backfilled with a foundation pit 21 after the reinforcement, and the roadbed 22 of the building is recovered after the foundation pit is backfilled. After the lacing bars are tensioned and fastened, a working well 19 with the size of 1.0m multiplied by 1.2m is built at the lacing bar fastening position outside the whole side limiting wall by using shale sintered bricks, so that the operations of maintaining the reserved head, compensating, fastening, tensioning and the like in the using process are facilitated. Waterproof cement mortar with the thickness of 10mm is smeared inside and outside the well wall, the working well is provided with a ladder stand for people to conveniently go in and out, a reinforced concrete cover plate is arranged at the well mouth, and a phi 710 cast iron well cover is additionally covered. And (5) filling and rolling the foundation pit on the outer side with the side limit strength layer by layer according to requirements. See figure 11 for details.