Advanced small guide pipe for tunnel
By designing an advanced small guide pipe body and grouting pipe structure, and using pistons and check valves to achieve uniform grouting, the problems of uneven grouting, slow speed and poor geological adaptability in tunnel construction have been solved, improving construction safety and efficiency and reducing costs.
Patent Information
- Application Number
- CN202520214777.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-11
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2035-02-11
AI Technical Summary
Existing tunnel pre-grouting methods with small guide pipes suffer from problems such as poor grouting uniformity, inaccurate grouting pressure control, slow grouting speed, and poor adaptability to complex geological conditions, resulting in low construction safety and efficiency, as well as serious material waste.
A structure comprising an advanced small guide tube body and an internal grouting pipe was designed. The grouting pipe has a piston and a check valve at its front end. Uniform grouting is achieved by controlling the movement of the piston through grouting pressure. The piston is made of elastic material and connected by threads. A limiting device prevents it from coming off. A spring-type check valve automatically closes the grouting port.
It achieves uniform and efficient grouting, improves the safety and efficiency of tunnel construction, reduces construction costs and material waste, and adapts to the construction needs of complex geological conditions.
Smart Images
Figure CN223482673U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of tunnel pre-support technology, and in particular to a tunnel pre-support small guide pipe. Background Technology
[0002] In tunnel construction, pre-support is one of the key measures to ensure the safety and stability of tunnel excavation. Pre-support grouting with small steel pipes, as an effective method, involves driving small steel pipes into the surrounding rock diagonally above or near the arch of the tunnel face before excavation and then grouting to improve the surrounding rock condition and ensure the stability of the tunnel face. However, existing pre-support grouting pipes and their grouting methods still have some shortcomings in practical applications, such as unstable grouting effects and slow construction progress.
[0003] For example, the traditional grouting process using pre-drilled small guide pipes in tunnels involves installing a grouting pipe at the tail of the guide pipe, allowing the grout to flow from the pipe opening to the bottom of the hole. This presents the following technical challenges: 1. Poor grouting uniformity: The diffusion of grout in the surrounding rock is often uneven, potentially resulting in some areas being fully grouted while others are under-grouted. This leads to inconsistent reinforcement effects, affecting the overall stability of the surrounding rock and failing to fully utilize the support function of the pre-drilled small guide pipe, thus increasing safety risks during tunnel construction. 2. Inaccurate grouting pressure control: It is difficult to precisely control the grouting pressure. If the grouting pressure is too low, the grout cannot effectively penetrate into the fissures of the surrounding rock, failing to achieve the expected reinforcement effect. If the grouting pressure is too high, it may cause splitting and damage to the surrounding rock, not only destroying the original structure of the surrounding rock but also potentially leading to surface heave, tunnel lining deformation, and other problems, seriously affecting the quality of tunnel construction and the safety of the surrounding environment. 3. Slow grouting speed: Traditional grouting techniques have a relatively slow grouting speed, which prolongs the construction time of a single grouting hole, thereby increasing the overall construction cycle of tunnel pre-support. This is detrimental to the efficient progress of tunnel engineering, potentially leading to delays and increased project costs, including equipment rental, labor costs, and management costs. 4. Significant grout waste: Due to uneven grouting and inaccurate pressure control, grout is often over-injected or injected into areas that do not require reinforcement, resulting in significant grout waste and increased construction material costs. Furthermore, improper disposal of waste grout can cause environmental pollution, such as contaminating groundwater and soil. 5. Poor adaptability to complex geological conditions: When encountering complex and variable geological conditions, such as fractured zones, water-rich strata, and weak surrounding rock, traditional grouting techniques struggle to adjust grouting parameters and methods promptly and effectively according to geological conditions. This leads to unsatisfactory grouting results and may even result in grouting failure, posing significant difficulties and safety hazards to tunnel construction. Utility Model Content
[0004] In view of the problems existing in the prior art, the present invention aims to provide a tunnel pre-support small guide pipe to achieve uniform and efficient grouting of pre-support, improve the safety of tunnel construction, and ensure the construction progress and quality of pre-support.
[0005] To achieve the above objectives, this utility model proposes a tunnel pre-conduit pipe, including a pre-conduit pipe body and a grouting pipe. The grouting pipe is disposed inside the pre-conduit pipe body, and its outer diameter is smaller than the inner diameter of the pre-conduit pipe body. A piston is detachably installed at the front end of the grouting pipe. The piston is sealed inside the pre-conduit pipe body. The front end of the piston is provided with several grouting holes, which communicate with the grouting pipe. A check valve for controlling the opening and closing of each grouting hole is provided inside the piston. The rear end of the grouting pipe is used to connect to grouting equipment. A limiting device for preventing the piston from falling out is provided on the inner wall of the rear end of the pre-conduit pipe body. 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 connects the grouting pipe to each grouting hole. Specifically, the grouting port is located at the rear end of the piston, and the grouting pipe is inserted into the grouting port and connects to each grouting hole.
[0007] In the above scheme: the check valve is a spring-loaded check valve, which is located at the connection between the grouting port and the piston. The grouting pressure controls the automatic opening or closing of the spring-loaded check valve. After grouting is completed, the grouting pipe is removed, and the spring-loaded check valve automatically closes the grouting port to prevent grout backflow.
[0008] In the above scheme: the piston is conical, and the grouting hole is located on the conical surface and tip of the piston. The piston can be made of an elastic material, such as rubber, which has a certain degree of 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 a threaded connection, which makes disassembly convenient.
[0010] In the above scheme: the limiting device is in the shape of a cone frustum, the inner diameter of the limiting device is larger than the outer diameter of the grouting pipe, the limiting device is used to stop the piston to prevent it from falling out, and will not interfere with the passage of the grouting pipe.
[0011] The beneficial effects of this utility model are: 1. Good grouting uniformity: Through the movement of the grouting pipe and piston during the grouting process, the grout can be evenly filled from the bottom of the hole to the opening, avoiding the problem of incomplete grouting in some areas that occurs in traditional grouting methods. This effectively improves the reinforcement effect of the surrounding rock and enhances the stability and safety of the tunnel. 2. High grouting efficiency: Due to the achievement of uniform and rapid grouting, compared with traditional grouting technology, the grouting time of a single advanced small guide pipe is greatly shortened, thereby improving the construction efficiency of the entire tunnel advanced support, helping to accelerate the tunnel construction progress and reduce construction costs. 3. Simple operation: No complicated equipment and processes are required, making it easy to promote and use. Attached Figure Description
[0012] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0013] Figure 1 It is a structural diagram of the present utility model.
[0014] Figure 2 This is a schematic diagram of the connection between the piston and the grouting pipe.
[0015] Figure 3 This is a detailed drawing of the limit device.
[0016] Figure 4 This is a schematic diagram of the initial stage of grouting using advanced small-diameter guide pipes.
[0017] Figure 5 This is a schematic diagram of the grouting process using advanced small guide pipes.
[0018] Figure 6 This is a schematic diagram of the completion of grouting using advanced small-diameter guide pipes. Detailed Implementation
[0019] like Figure 1 As shown in Figure 6, a tunnel pre-conduit pipe mainly consists of a pre-conduit pipe body 1 and a grouting pipe 2. The grouting pipe 2 is located inside the pre-conduit pipe body 1, and its outer diameter is smaller than the inner diameter of the pre-conduit pipe body 1 so that it can move freely within the pre-conduit pipe body 1. Specifically, the pre-conduit pipe body 1 is made of Φ42×4mm hot-rolled seamless steel pipe, and the grouting pipe 2 is made of Φ22×3mm hot-rolled seamless steel pipe.
[0020] A piston 3 is detachably installed at the front end of the grouting pipe 2. The piston 3 is sealed inside the body of the advanced small guide tube 1. The front end of the piston 3 is provided with several grouting holes, which are connected to the grouting pipe 2. A check valve for controlling the opening and closing of each grouting hole is provided inside the piston 3.
[0021] The rear end of the grouting pipe 2 is used to connect to the grouting equipment. The inner wall of the rear end of the advanced small guide tube body 1 is provided with a limiting device 4 to prevent the piston 3 from falling out. The grouting pipe 2 can pass through the limiting device 4.
[0022] Ideally, the piston 3 is provided with a grouting port for the insertion of the grouting pipe 2, and the grouting port connects the grouting pipe 2 to each grouting hole. Specifically, the grouting port is located at the rear end of the piston 3, and the grouting pipe 2 is inserted into the grouting port and connected to each grouting hole.
[0023] Ideally, the check valve should be a spring-loaded check valve, located at the connection between the grouting port and piston 3. The grouting pressure should control the spring-loaded check valve to automatically open or close. After grouting is complete, the grouting pipe 2 can be removed, and the spring-loaded check valve will automatically close the grouting port to prevent backflow of grout.
[0024] Ideally, piston 3 is conical, with the grouting hole located on the conical surface and tip of piston 3. Piston 3 can be made of an elastic material, such as rubber, possessing a certain degree of flexibility and sealing performance, while also being able to withstand a certain grouting pressure without being damaged.
[0025] Ideally, piston 3 and grouting pipe 2 should be connected by thread for easy disassembly.
[0026] Ideally, the limiting device 4 is in the shape of a cone frustum, 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 stop the piston 3 to prevent it from falling out, and will not interfere with the passage of the grouting pipe 2.
[0027] The working principle of this utility model is as follows:
[0028] When the grouting equipment is started, the grout is injected into the gap between the pre-drilled 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 grout, which drives the grouting pipe 1 to move towards the borehole opening. During the movement, the grout continuously fills the gap, achieving uniform grouting.
Claims
1. A tunnel pre-conduit, comprising a pre-conduit body (1), characterized in that: It also includes a grouting pipe (2), which is located inside the pre-conduit body (1). Its outer diameter is smaller than the inner diameter of the pre-conduit body (1). A piston (3) is detachably installed at the front end of the grouting pipe (2). The piston (3) is sealed inside the pre-conduit body (1). The front end of the piston (3) is provided with several grouting holes. The grouting holes are connected to the grouting pipe (2). A check valve for controlling the opening and closing of each grouting hole is provided inside the piston (3). The rear end of the grouting pipe (2) is used to connect to the grouting equipment. A limiting device (4) for preventing the piston (3) from falling out is provided on the inner wall of the rear end of the pre-conduit body (1). The grouting pipe (2) can pass through the limiting device (4).
2. The tunnel pre-conduit pipe according to claim 1, characterized in that: The piston (3) is provided with a grouting port for the grouting pipe (2) to be inserted, and the grouting port is connected between the grouting pipe (2) and each grouting hole.
3. The tunnel pre-conduit pipe according to claim 2, characterized in that: The check valve is a spring-loaded check valve, which is located at the connection between the grouting port and the piston (3). The spring-loaded check valve is automatically opened or closed by the grouting pressure.
4. The tunnel pre-conduit pipe according to claim 2, characterized in that: The piston (3) is conical, and the grouting hole is located on the conical surface and tip of the piston (3).
5. The tunnel pre-conduit pipe according to claim 1, characterized in that: The piston (3) and the grouting pipe (2) are connected by threads.
6. The tunnel pre-conduit pipe according to claim 1, characterized in that: The limiting device (4) is in the shape of a cone frustum, and the inner diameter of the limiting device (4) is larger than the outer diameter of the grouting pipe (2).