Tunnel advanced small guide pipe and grouting method thereof

Abstract

The tunnel advanced small guide pipe comprises an advanced small guide pipe body and further comprises a grouting pipe, the grouting pipe is arranged in the advanced small guide pipe body, the outer diameter of the grouting pipe is smaller than the inner diameter of the advanced small guide pipe body, a piston is detachably installed at the front end of the grouting pipe, and the front end of the grouting pipe is provided with a piston rod. The piston is sealed and plugged in the advanced small guide pipe body, a plurality of grouting holes are formed in the front end of the piston and communicated with the grouting pipe, check valves used for controlling the grouting holes to be opened and closed are arranged in the piston, a limiting device used for preventing the piston from disengaging is arranged on the inner wall of the rear end of the advanced small guide pipe body, and the grouting pipe can penetrate out of the limiting device. The grouting uniformity is good, the grout can be gradually and uniformly filled from the hole bottom to the hole opening during grouting, the problem that local grouting is not full in a traditional grouting method is solved, the reinforcing effect of surrounding rock is effectively improved, and the stability and safety of a tunnel are enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, in particular to a tunnel advance small conduit and a grouting method thereof. Background Art

[0002] In tunnel construction, advance support is one of the key measures to ensure the safety and stability of tunnel excavation. As an effective advance support method, advance small pipe grouting is used to drive a small steel pipe into the surrounding rock above or near the arch of the face before excavation to improve the surrounding rock condition and ensure the stability of the face. However, the existing advance small pipe and its grouting method still have some shortcomings in practical application, such as unstable grouting effect and slow construction progress.

[0003] For example, the traditional grouting process of the tunnel advance small guide tube adopts the installation of the grouting pipe at the tail of the guide tube, so that the slurry flows from the pipe mouth to the bottom of the hole, which has the following technical difficulties: 1. Poor grouting uniformity: The diffusion of slurry in the surrounding rock is often not uniform, which may lead to full grouting in some areas and insufficient grouting in some areas, resulting in uneven reinforcement effects, affecting the improvement of the overall stability of the surrounding rock, and failing to give full play to the support role of the advance small guide tube, increasing the safety risk during tunnel construction. 2. Inaccurate grouting pressure control: It is difficult to accurately control the grouting pressure. If the grouting pressure is too small, the slurry cannot effectively penetrate into the cracks of the surrounding rock and cannot achieve the expected reinforcement effect; if the grouting pressure is too large, it may cause the splitting and destruction of the surrounding rock, which not only destroys the original structure of the surrounding rock, but also may cause problems such as surface uplift and deformation of the tunnel lining, seriously affecting the quality of tunnel construction and the safety of the surrounding environment. 3. Slow grouting speed: The grouting speed of traditional technology is relatively low, which will prolong the construction time of a single grouting hole, and then increase the construction period of the entire tunnel advance support, which is not conducive to the efficient advancement of tunnel engineering, and may cause delays in construction period and increase engineering costs, including equipment rental, labor costs and management costs. 4. Serious waste of slurry: Due to uneven grouting and imprecise pressure control, slurry is often over-injected or injected into areas that do not require reinforcement, resulting in a large amount of slurry waste and increasing construction material costs. At the same time, if the waste slurry is not handled properly, it will also cause certain pollution to the environment, such as contaminating groundwater and soil. 5. Poor adaptability to complex geological conditions: When encountering complex and changeable geological conditions, such as broken zones, water-rich strata, weak surrounding rocks, etc., traditional grouting technology is difficult to adjust grouting parameters and methods in a timely and effective manner according to geological conditions, resulting in unsatisfactory grouting effects, and even grouting failures, which brings great difficulties and safety hazards to tunnel construction. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention aims to provide a tunnel advance small duct and a grouting method thereof, so as to achieve uniform and efficient grouting of advance support, improve the safety of tunnel construction, and ensure the construction progress and quality of advance support.

[0005] In order to achieve the above-mentioned purpose, the present invention proposes a tunnel advance small catheter, comprising an advance small catheter body and a grouting pipe, wherein the grouting pipe is arranged inside the advance small catheter body, and its outer diameter is smaller than the inner diameter of the advance small catheter body, and a piston is detachably installed at the front end of the grouting pipe, and the piston is sealed inside the advance small catheter body, and a plurality of grouting holes are provided at the front end of the piston, and the grouting holes are communicated with the grouting pipe, and a check valve for controlling the opening and closing of each grouting hole is provided inside the piston, and a limiting device for preventing the piston from falling out is provided on the inner wall at the rear end of the advance small catheter body, and the grouting pipe can pass through the limiting device.

[0006] In the above scheme: the piston is provided with a grouting port for inserting a grouting pipe, and the grouting port is connected between the grouting pipe and each grouting hole. Specifically, the grouting port is arranged at the rear end of the piston, and the grouting pipe is inserted into the grouting port and connected with each grouting hole.

[0007] In the above scheme: the check valve is a spring check valve, which is arranged at the connection position between the grouting port and the piston, and the spring check valve is automatically opened or closed by the grouting pressure. After the grouting is completed, the grouting pipe is removed, and the grouting port can be automatically closed with the help of the spring check valve to prevent the slurry from flowing back.

[0008] In the above scheme: the piston is conical, and the grouting holes are arranged on the conical surface and the tip of the piston. The piston can be made of elastic material, such as rubber, etc., which has certain flexibility and sealing performance, and can withstand a certain grouting pressure without being damaged.

[0009] In the above scheme: the piston and the grouting pipe are connected by threads, which is convenient for disassembly.

[0010] In the above scheme: the limiting device is in the shape of a conical cone, the inner diameter of the limiting device is larger than the outer diameter of the grouting pipe, the limiting device is used to resist the piston to prevent it from falling out, and will not interfere with the passage of the grouting pipe.

[0011] The present invention also proposes a grouting method for a tunnel advance small conduit. Based on the tunnel advance small conduit, the grouting method comprises the following steps:

[0012] S1. Determine the installation position and angle of the advance small guide tube on the tunnel face, and use drilling equipment to drill holes at the predetermined positions;

[0013] S2. Insert the small advance guide tube into the borehole, ensure that the front end of the small advance guide tube reaches the designed depth and is in close contact with the surrounding rock, and install a slurry stopper at the tube mouth to seal the gap between the borehole wall and the small advance guide tube;

[0014] S3, connecting the rear end of the grouting pipe to the grouting equipment, and extending the front end of the grouting pipe into the front end of the leading small guide tube body to ensure that the slurry can be injected from the bottom of the borehole;

[0015] S4, start the grouting equipment, and inject the slurry into the gap between the advance small guide tube body and the surrounding rock through the grouting pipe. As the grouting pressure increases, the piston is pushed by the slurry, driving the grouting pipe to move toward the borehole. During the movement, the slurry continuously fills the gap to achieve uniform grouting;

[0016] S5. When the piston moves to the position of the limit device, stop grouting, remove the grouting pipe, and close the check valve.

[0017] In the above scheme: the grouting pipe is cleaned and inspected after being removed, and is used for the grouting operation of the next advance small guide tube body, that is, the grouting pipe can be recycled, which is conducive to cost saving.

[0018] The beneficial effects of the present invention are:

[0019] 1. Good grouting uniformity: Through the movement of the grouting pipe and the piston during the grouting process, the slurry can be gradually and evenly filled from the bottom of the hole to the hole mouth, avoiding the problem of partial grouting insufficiency in traditional grouting methods, effectively improving the reinforcement effect of the surrounding rock, and enhancing the stability and safety of the tunnel.

[0020] 2. High grouting efficiency: Due to the realization of uniform and rapid grouting, compared with traditional grouting technology, the grouting time of a single advance small guide tube is greatly shortened, thereby improving the construction efficiency of the entire tunnel advance support, helping to speed up the progress of tunnel construction and reduce construction costs.

[0021] 3. Easy to operate: It does not require complicated equipment and processes, and is easy to promote and use. Construction workers can master the technology after simple training. The technical difficulty is low, and it effectively reduces human errors during the construction process and improves construction quality and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 It is a schematic diagram of the connection between the piston and the grouting pipe.

[0025] Figure 3 This is a large-scale drawing of the limit device.

[0026] Figure 4 This is a schematic diagram of the initial stage of advance small-duct grouting.

[0027] Figure 5 It is a schematic diagram of the mid-stage of advance small-duct grouting.

[0028] Figure 6 This is a schematic diagram of the completion of advanced small-duct grouting. DETAILED DESCRIPTION

[0029] like Figure 1 As shown in FIG. 6 , a tunnel advance small conduit is mainly composed of an advance small conduit body 1 and a grouting pipe 2. The grouting pipe 2 is arranged inside the advance small conduit body 1, and its outer diameter is smaller than the inner diameter of the advance small conduit body 1, so that it can move freely inside the advance small conduit body 1. Specifically, the advance small conduit body 1 adopts a Φ42×4mm hot-rolled seamless steel pipe, and the grouting pipe 2 adopts a Φ22×3mm hot-rolled seamless steel pipe.

[0030] The front end of the grouting pipe 2 is detachably mounted with a piston 3, which is sealed inside the advance small catheter body 1. A plurality of grouting holes are provided at the front end of the piston 3, which are communicated with the grouting pipe 2, and a check valve for controlling the opening and closing of each grouting hole 2 is provided inside the piston 3.

[0031] A limiting device 4 for preventing the piston 3 from falling out is provided on the inner wall of the rear end of the leading small conduit body 1 , and the grouting pipe 2 can pass through the limiting device 4 .

[0032] Preferably, the piston 3 is provided with a grouting port for inserting the grouting pipe 2, and the grouting port is communicated between the grouting pipe 2 and each grouting hole. Specifically, the grouting port is arranged at the rear end of the piston 3, and the grouting pipe 2 is inserted into the grouting port and communicated with each grouting hole.

[0033] Preferably, the check valve is a spring check valve, which is arranged at the connection position between the grouting port and the piston 3, and the spring check valve is automatically opened or closed by the grouting pressure. After the grouting is completed, the grouting pipe 2 is removed, and the grouting port can be automatically closed with the help of the spring check valve to prevent the slurry from flowing back.

[0034] Preferably, the piston 3 is tapered, and the grouting holes are arranged on the tapered surface and the tip of the piston 3. The piston 3 can be made of elastic material, such as rubber, etc., which has certain flexibility and sealing performance, and can withstand a certain grouting pressure without being damaged.

[0035] Preferably, the piston 3 and the grouting pipe 2 are connected by threads, which is convenient for disassembly.

[0036] Preferably, the limiting device 4 is in the shape of a conical cone, and the inner diameter of the limiting device 4 is larger than the outer diameter of the grouting pipe 2. The limiting device 4 is used to resist the piston 3 to prevent it from falling out, and will not interfere with the passage of the grouting pipe 2.

[0037] A grouting method for a tunnel advance small conduit, based on the above-mentioned tunnel advance small conduit, the grouting method mainly consists of the following steps:

[0038] S1. Determine the installation position and angle of the advance small guide tube on the tunnel face, and use drilling equipment to drill a hole at the predetermined position. The drilling diameter is slightly larger than the outer diameter of the advance small guide tube body 1, generally the outer diameter of the advance small guide tube body 1 plus 10 to 20 mm. During the insertion of the advance small guide tube body 1, a drilling rig can be used to assist in entering the hole, so that the advance small guide tube body 1 is firmly installed.

[0039] S2, insert the advance small catheter into the borehole, ensure that the front end of the advance small catheter reaches the designed depth and is in close contact with the surrounding rock, and install the grouting plug 5 at the pipe mouth to seal the gap between the borehole wall and the advance small catheter, and prevent the slurry from flowing back in the gap between the advance small catheter and the hole wall. Specifically, after the advance small catheter body 1 is installed, the grouting pipe 2 can be connected to the piston 3 reserved in the advance small catheter body 1.

[0040] S3, connect the rear end of the grouting pipe 2 to the grouting equipment, and extend the front end of the grouting pipe 2 into the inner front end of the advance small conduit body 1, generally with an insertion depth of 0.5 to 1.0 meters, to ensure that the slurry can be injected from the bottom of the borehole. The length of the grouting pipe 2 is determined according to the length of the advance small conduit body 1, to ensure that the grouting pipe 2 can extend from the bottom of the hole to the hole mouth, and to reserve a certain connection length for connecting the grouting equipment.

[0041] S4, start the grouting equipment, and inject the slurry into the gap between the advance small guide tube body 1 and the surrounding rock through the grouting pipe 2. As the grouting pressure increases, the piston 3 is pushed by the slurry, driving the grouting pipe 1 to move toward the borehole orifice. During the movement, the slurry continuously fills the gap to achieve uniform grouting.

[0042] S5. When the piston 3 moves to the position of the limit device 4, stop grouting, remove the grouting pipe 2, and close the check valve. The spring-loaded check valve can automatically close after the grouting pipe 2 is removed.

[0043] Preferably, the grouting pipe 2 is removed, cleaned and inspected, and then used for the grouting operation of the next leading small conduit body 1, that is, the grouting pipe 2 can be recycled, which is conducive to cost saving.

Claims

1. A tunnel advance catheter, comprising an advance catheter body (1), characterized in that: It also comprises a grouting pipe (2), wherein the grouting pipe (2) is arranged inside the advance small conduit body (1), and its outer diameter is smaller than the inner diameter of the advance small conduit body (1). A piston (3) is detachably mounted on the front end of the grouting pipe (2), and the piston (3) is sealed inside the advance small conduit body (1). A plurality of grouting holes are arranged at the front end of the piston (3), and the grouting holes are communicated with the grouting pipe (2). A check valve for controlling the opening and closing of each grouting hole (2) is arranged inside the piston (3). A limiting device (4) for preventing the piston (3) from falling out is arranged on the inner wall at the rear end of the advance small conduit body (1), and the grouting pipe (2) can pass through the limiting device (4).

2. The tunnel advance catheter according to claim 1, characterized in that: The piston (3) is provided with a grouting port for inserting the grouting pipe (2), and the grouting port is connected between the grouting pipe (2) and each grouting hole.

3. The tunnel advance catheter according to claim 2, characterized in that: The check valve is a spring check valve, which is arranged at the connection position between the grouting port and the piston (3), and is automatically opened or closed by controlling the grouting pressure.

4. The tunnel advance catheter according to claim 2, characterized in that: The piston (3) is conical, and the grouting holes are arranged on the conical surface and the tip of the piston (3).

5. The tunnel advance catheter according to claim 1, characterized in that: The piston (3) is connected to the grouting pipe (2) by means of threads.

6. The tunnel advance catheter according to claim 1, characterized in that: The limiting device (4) is in the shape of a conical frustum, and the inner diameter of the limiting device (4) is greater than the outer diameter of the grouting pipe (2).

7. A grouting method for a tunnel advance small conduit according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Determine the installation position and angle of the advance small guide tube on the tunnel face, and use drilling equipment to drill holes at the predetermined positions; S2, inserting the advance small guide tube into the borehole, ensuring that the front end of the advance small guide tube reaches the designed depth and is in close contact with the surrounding rock, and installing a slurry stopper (5) at the tube mouth to seal the gap between the borehole wall and the advance small guide tube; S3, connecting the rear end of the grouting pipe (2) to the grouting equipment, and extending the front end of the grouting pipe (2) into the front end of the leading small guide tube body (1) to ensure that the slurry can be injected from the bottom of the borehole; S4, starting the grouting equipment, injecting the slurry into the gap between the leading small guide tube body (1) and the surrounding rock through the grouting pipe (2), and as the grouting pressure increases, the piston (3) is pushed by the slurry, driving the grouting pipe (1) to move toward the borehole orifice, and during the movement, the slurry continuously fills the gap to achieve uniform grouting; S5. When the piston (3) moves to the position of the limit device (4), stop grouting, remove the grouting pipe (2), and close the check valve.

8. The grouting method for the tunnel advance small conduit according to claim 7 is characterized in that: The grouting pipe (2) is removed, cleaned and inspected, and is used for the grouting operation of the next leading small guide tube body (1).

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