Horizontal directional grouting method for reinforcing roadbed

Abstract

The application relates to a horizontal directional grouting reinforced roadbed construction method and relates to the field of roadbed construction. The method is mainly used for solving the problem that the current ground vertical grouting reinforcement before pipe jacking construction influences traffic and environment. Three layers of holes arranged in the up-down direction are drilled in the grouting reinforced area, each layer comprises a plurality of holes, the hole axes of the holes in the middle layer are parallel to the axis of the installed pipe, the holes in the innermost layer are all inclined to the left side, the holes in the outermost layer are all inclined to the right side, a drilling machine is installed, holes are drilled at a certain drilling angle, downward deviation drilling is performed, after a certain length of arc track, horizontal direction drilling is performed when the drilling design depth is reached, after the horizontal grouting section drilling is completed, upward deviation drilling is performed at a certain angle to reach the unearthing point. The drill bit is connected with a grouting flower pipe and back dragging is performed. After the flower pipe reaches the unearthing point, the one end of the flower pipe is blocked, the other end is connected with a grouting pipeline, and horizontal directional grouting is started. The method has the advantages of small influence on traffic and environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of roadbed construction, in particular to a roadbed grouting reinforcement construction method. BACKGROUND

[0002] With the continuous improvement of infrastructure construction technology in China, pipe jacking construction method as an advanced trenchless construction method is widely used in municipal pipeline, subway, public utilities, water and electricity application and other construction fields due to its small construction area, environmental protection and small disturbance to road traffic and buildings.

[0003] In order to effectively control ground subsidence, traffic diversion and ground vertical grouting reinforcement of the road surface and the ground within the range of the two side slopes are required before pipe jacking construction, and the road surface within the grouting reinforcement range needs to be repaired afterwards. However, when the traffic volume is large, heavy vehicles are more and the construction site is limited by conditions and it is not easy to use ground vertical grouting, using ground grouting reinforcement not only has high engineering cost, affects traffic, but also easily affects the environment. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a horizontal directional grouting reinforcement roadbed construction method which has simple construction procedure, low engineering cost and small influence on traffic and environment.

[0005] To solve the above technical problems, the present application adopts the following technical scheme: construction is carried out according to the steps of construction preparation, drilling guide hole, back pulling flower pipe and grouting reinforcement.

[0006] The range of 2 meters above 180° (i.e. above the horizontal radial center line of the installed pipe) of the pipe jacking installation position is the grouting reinforcement zone, and the installation position of the pipe jacking below 180° is not grouted; a plurality of holes arranged in three layers are drilled in the grouting reinforcement zone, each layer includes a plurality of holes arranged in a semicircle around the pipe jacking installation position in a ring shape, wherein the plurality of holes in the innermost layer are arranged around the outside of the upper half of the pipe jacking installation position, the plurality of holes in the middle layer are arranged around the outside of the plurality of holes in the innermost layer, and the plurality of holes in the outermost layer are arranged around the outside of the plurality of holes in the middle layer, and the distance between the center of each hole in the same layer and the center of the installed pipe is the same. During construction, the holes are drilled and grouted from the inside to the outside, and the skip hole grouting method is used when drilling and grouting the holes in the same layer; wherein the positions of the holes in the middle layer are staggered with the positions of the holes in the outermost layer and the innermost layer.

[0007] The axis of each channel of the innermost layer is inclined to the left, and the angle between the axis of each channel and the axis of the installed pipe is 10-15° (the angle is on the left side of the axis of the pipe). The axis of each channel of the outermost layer is inclined to the right, and the angle between the axis of each channel and the axis of the installed pipe is -10--15° (the angle is on the right side of the axis of the pipe).

[0008] The horizontal guiding hole is drilled by a caterpillar horizontal drilling machine, and the positions of the earth-in point, the earth-out point and the center axis of the grouting hole are released. After the drilling machine is installed and its stability is ensured, the hole is drilled at a certain drilling angle (10-15° to the underground, and the drilling angle is determined by the angle between the incident angle of the drilling rod of the caterpillar drilling machine and the horizontal plane), and the hole is drilled downward. The direction of the drilling head is controlled by a directional drilling guide on the upper part of the road. After a certain length of arc trajectory, the direction of the drilling head is adjusted to the horizontal direction, and then the drilling head is rotated horizontally to ensure that the drilling hole reaches the designed accurate elevation. After the horizontal grouting section is drilled, the hole is drilled upward at a certain angle (10-15°) until the earth-out point is reached.

[0009] Drilling fluid (obtained by mixing bentonite, caustic soda and water) is continuously provided during drilling. The drilling fluid has the functions of cooling the drilling head, lubricating the drilling tool, and more importantly, suspending and carrying the drilling cuttings, so that the mixed drilling cuttings are smoothly discharged out of the hole in the form of flowing mud, which not only provides sufficient annular space for the back-dragging flower pipe, but also reduces the weight and resistance of the back-dragging flower pipe. The mud remaining in the hole can play a role in protecting the wall.

[0010] After the drilling head reaches the earth-out point, the grouting flower pipe is connected and back-dragged. The grouting flower pipe is a φ50mm PE pipe, and a plurality of grouting holes are opened in the axial direction in the grouting section (i.e. the horizontal section of the grouting flower pipe). The distance between every two adjacent grouting holes in each row is 5cm, and the positions of the grouting holes in adjacent rows are staggered, so that the grouting holes on the grouting flower pipe are arranged in the form of a plum blossom. Before back-dragging, the process of connecting the flower pipes is performed, and the multiple flower pipes are connected into a pipe with a length corresponding to the length of the hole by hot melting. An iron wire is placed in the flower pipe during back-dragging of the flower pipe.

[0011] After the flower pipe reaches the earth-out point, one end of the flower pipe is plugged, and the other end is connected with the grouting pipeline, and horizontal directional grouting (i.e. grouting of the horizontal section of the flower pipe) is started. The grouting pressure is controlled at 0.5-1.5MPa, and the grouting is performed by using cement slurry with a water-cement ratio of 1:1.

[0012] The above operations are repeated until the grouting construction is completed.

[0013] The advantage of the present application is that not only multiple layers of flower pipes are arranged, but also an iron wire is arranged in each flower pipe, which mainly plays a role of anti-pulling during grouting, and the horizontal projection of the multiple layers of flower pipes is interwoven, a grouting network of "crisscross" is formed through grouting, and finally the roadbed is reinforced.

[0014] The method has the advantages of simple construction procedure, less construction land occupation, low engineering cost, fast construction speed, and small influence on traffic and environment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of drilling a guide hole in the present application;

[0016] Figure 2 is a schematic diagram of back pulling of grouting flower pipes in the present application;

[0017] Figure 3 is Figure 2 A-A view of the present application;

[0018] Figure 4 is a schematic diagram of the structure of grouting flower pipes in the present application;

[0019] Figure 5 is a schematic diagram of the grouting hole projection in the present application.

[0020] In the figure: 1, crawler-type horizontal drilling machine; 2, drill bit; 3, grouting flower pipe; 31, hole; 4, iron wire; 5, pipe jacking installation position; 6, innermost hole; 7, middle layer hole; 8, outermost hole. DETAILED DESCRIPTION

[0021] The present application will be further described below in combination with Figures 1-5 ;

[0022] According to the steps of construction preparation, drilling a guide hole, back pulling a flower pipe, and grouting reinforcement, the construction is carried out.

[0023] The grouting reinforcement zone is 2 meters above the range of 180° of the pipe jacking installation position (i.e. above the horizontal radial center line of the installed pipe jacking), and no grouting is performed below 180° of the pipe jacking installation position; three layers of holes are drilled and grouted in the grouting reinforcement zone, each layer including a plurality of holes arranged in a semicircle around the pipe jacking installation position, wherein the holes in the innermost layer are arranged around the upper half of the pipe jacking installation position, the holes in the middle layer are arranged around the holes in the innermost layer, and the holes in the outermost layer are arranged around the holes in the middle layer; the distance between the center of each hole in the same layer and the center of the installed pipe jacking is the same. The holes are drilled and grouted from the inside to the outside in sequence, and the skip-hole grouting method is used when drilling and grouting the holes in the same layer; the positions of the holes in the middle layer are staggered with the positions of the holes in the outermost layer and the innermost layer.

[0024] The axes of the holes in the middle layer are parallel to the axis of the installed pipe jacking, the holes in the innermost layer are all inclined to the left, and the inclination angle is the included angle between the axis of each hole and the axis of the installed pipe jacking, which is 10-15° (the included angle is on the left side of the axis of the pipe jacking), and the holes in the outermost layer are all inclined to the right, and the inclination angle is the included angle between the axis of each hole and the axis of the installed pipe jacking, which is -10 to -15° (the included angle is on the right side of the axis of the pipe jacking).

[0025] In the first step, the horizontal directional drilling and grouting method is used for long-distance grouting construction, and the drilling equipment, pipe pulling equipment, grouting pipe material and various consumables need to be brought in advance. Through stratum exploration and underground pipeline detection, the positions of the relevant stratum, underground water, underground existing pipelines and other buried objects are understood, which provides a basis for selecting drilling methods, preparing drilling fluid and designing drilling trajectories.

[0026] In the second step, a crawler-type horizontal drilling machine is used to drill the horizontal guide hole, which can move automatically under the condition of small slope and is flexible. According to the requirements of the construction drawings, the positions of the earth entry point, the earth exit point and the center axis of the grouting hole are laid out, the drilling machine installation position is measured and determined outside the earth entry point at a certain distance from the edge of the road, the drilling machine is installed, and then the drilling machine is tested to ensure its stability, and then the hole is drilled at a certain drilling angle (10-15° downward drilling, the drilling angle is determined by the included angle between the crawler-type drilling rod incident angle and the horizontal plane), the direction of the drilling head is controlled by the directional drilling guide instrument on the upper part of the road, and after a certain length of arc trajectory, the direction of the drilling head is adjusted to the horizontal direction, and then the drilling is continued horizontally to ensure that the drilling reaches the designed accurate elevation. After the horizontal grouting section drilling is completed, the drilling is upwardly inclined at a certain angle (10-15°) until the earth exit point is reached.

[0027] Drilling fluid (drilling fluid is mixed by bentonite and caustic soda with water) needs to be provided continuously. Drilling fluid has the functions of cooling drill bit, lubricating drilling tool, and more importantly, suspending and carrying drill cuttings, so that mixed drill cuttings are discharged out of the hole as flowing mud, which provides sufficient annular space for back dragging flower pipe and reduces the weight and resistance of back dragging flower pipe. The mud remaining in the hole can play a role in wall protection.

[0028] The third step is to connect the grouting flower pipe after the drill bit reaches the unearthing point and to back drag. The grouting flower pipe adopts φ50mm PE pipe, and a plurality of grouting holes are opened in the axial direction along the grouting section (i.e. the horizontal section of the grouting flower pipe), the distance between every two grouting holes in the same row is 5cm, and the positions of the grouting holes in adjacent rows are staggered, so that the grouting holes on the grouting flower pipe are arranged in a plum blossom shape. The procedure of flower pipe connection is performed before back dragging, and a plurality of flower pipes are connected into a pipeline with a length corresponding to the hole length by hot melting method. An 8# iron wire is placed in the flower pipe, and the flower pipe is back dragged together when the flower pipe is back dragged. The operator uniformly and smoothly pulls the flower pipe and cannot pull it hard.

[0029] The fourth step is to block one end of the flower pipe after the flower pipe reaches the soil entering point, connect the other end with the grouting pipeline, and start horizontal directional grouting (i.e. grouting of the horizontal section of the flower pipe). The grouting pressure is controlled at 0.5-1.5MPa, and cement slurry is used for grouting, with a water-cement ratio of 1:1.

[0030] The above-mentioned second to fourth steps are repeated until the grouting construction is completed.

[0031] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a horizontally directional grouting reinforcement subgrade, characterized in that: The grouting reinforcement zone is 2 meters above the 180° range of the pipe jacking installation position, and no grouting is performed below the 180° range of the pipe jacking installation position; three layers of holes are drilled and grouted in the grouting reinforcement zone, each layer including a plurality of holes arranged in a semicircle along the annular arrangement of the pipe jacking installation position, wherein the holes in the innermost layer are arranged around the outside of the upper half of the pipe jacking installation position, the holes in the middle layer are arranged around the outside of the holes in the innermost layer, and the holes in the outermost layer are arranged around the outside of the holes in the middle layer; the distance between the center of each hole in the same layer and the center of the pipe after installation is the same; drilling and grouting are performed sequentially from the inside out, and the skip-hole grouting method is used when drilling and grouting holes in the same layer; the positions of the holes in the middle layer are staggered with the positions of the holes in the outermost layer and the innermost layer; wherein the axes of the holes in the middle layer are parallel to the axis of the pipe after installation, the holes in the innermost layer are all inclined to the left, the inclination angle between the axis of each hole and the axis of the pipe after installation is 10-15°, and the inclination angle is located to the left of the axis of the pipe; the holes in the outermost layer are all inclined to the right, the inclination angle between the axis of each hole and the axis of the pipe after installation is -10 to -15°, and the inclination angle is located to the right of the axis of the pipe; In the first step, horizontal directional drilling and grouting is used as the long-distance grouting construction method, and drilling equipment, pipe pulling equipment, grouting pipes, and various consumables need to be brought to the site in advance; through stratum exploration and underground pipeline detection, the positions of the relevant stratum, underground water, underground existing pipelines, and other buried objects are understood, providing a basis for selecting drilling methods, preparing drilling fluid, and designing drilling trajectories; In the second step, a crawler-type horizontal drilling machine is used to drill a horizontal guide hole, and the positions of the entry point, exit point, and central axis of the grouting hole are released; after the drilling machine is installed, the hole is opened at a certain drilling angle, and drilling is performed downwardly and obliquely upwardly; the direction of the drilling head is controlled by a directional drilling guide instrument on the upper part of the road surface; after a certain length of arc trajectory, the direction of the drilling head is adjusted to the horizontal direction, and drilling is then performed horizontally and rotationally to ensure that the drilling reaches the designed accurate elevation; after the horizontal grouting section is drilled, drilling is performed obliquely upwardly until the exit point is reached; In the third step, after the drilling head reaches the exit point, the grouting flower pipe is connected and back-reaming is performed; before back-reaming, multiple flower pipes are connected into a pipe with a length corresponding to the length of the hole by hot melting; an iron wire is placed in the flower pipe during back-reaming of the flower pipe, and the iron wire is back-reamed together with the flower pipe; In the fourth step, after the flower pipe reaches the exit point, one end of the flower pipe is plugged, the other end is connected with the grouting pipeline, and horizontal directional grouting is started; the above-mentioned second to fourth steps are repeated until the grouting construction is completed.

2. The method for constructing a horizontally oriented grouting reinforced subgrade according to claim 1, characterized in that: The grouting flower pipe is a φ50mm PE pipe, a plurality of rows of grouting holes are opened in the axial direction along the grouting section, the distance between every two adjacent grouting holes in each row is 5cm, and the positions of the grouting holes in adjacent rows are staggered, so that the grouting holes on the grouting flower pipe are arranged in a plum blossom shape.

3. The method for constructing a horizontally oriented grouting reinforced subgrade according to claim 1 or 2, characterized in that: The grouting pressure is controlled at 0.5-1.5MPa, and cement slurry is used for grouting, with a water-cement ratio of 1:1.

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