Tunnel Thermal Conductive Fracture Heat Insulation Reinforcement Grouting Blocking Method and Grouting Pipe

Abstract

The present invention discloses a method for heat-conducting fracture heat insulation reinforcement grouting interruption in tunnels and a grouting pipe, as follows: Step 1, constructing a grout stop wall: determining the reinforcement range and the heat insulation range; constructing a grout stop wall in front of the heading face, and the outer contour of the grout stop wall is located outside the tunnel excavation contour line; Step 2, reinforcement curtain grouting: constructing reinforcement grouting holes on the grout stop wall and within the tunnel excavation contour line, and injecting a cement-based grouting material into the surrounding rock; Step 3, constructing heat insulation grouting holes: constructing heat insulation grouting holes on the grout stop wall and outside the tunnel excavation contour line, and inserting a grouting pipe into the heat insulation grouting holes; Step 4, heat insulation curtain grouting: injecting a heat insulation composite chemical slurry from the rear end of the grouting pipe, flowing to the front end and injecting it into the surrounding rock, and solidifying. During the curtain grouting construction process in high geothermal areas using this method, a permanent heat insulation cylinder layer surrounding the tunnel is formed, realizing the dual functions of reinforcement and heat insulation, and having a good heat insulation effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel engineering, and particularly relates to a grouting blocking method for heat conduction fracture insulation reinforcement of tunnels and a grouting pipe. Background Art

[0002] For railways passing through the Hengduan Mountains, the tunnel has a large buried depth and active geological movements, and often encounters the problem of heat conduction fractures (layers) with high geotemperature. The rock temperature of the tunnel reaches 40°C to 60°C. The tunnel passes through three heat conduction fractures (layers), and the local hot water gushing temperature is as high as 60°C. If no reinforcement and heat insulation measures are taken, the tunnel may not be able to be built and become an abandoned project.

[0003] For high geotemperature tunnels with a rock temperature less than 40°C, during construction, heat insulation and cooling design schemes are often adopted, mainly including high-power ventilation and heat insulation lining structure design. Among them, high-power ventilation needs to be maintained for a long time, with high energy consumption and relatively low cooling efficiency; the lining structure design adopts measures such as increasing the lining thickness and adding heat insulation layers, which are one-time investments, but the excavation area is large, and the final effective net space is small, and the comprehensive cost of construction and materials is very high. For heat conduction fractures (layers) with a rock temperature higher than 40°C and hot water gushing at 60°C in the crossing section, if the above methods are adopted, the cost is even higher. Therefore, in the tunnel construction in high geothermal areas, a permanent construction scheme with good heat insulation effect and low cost is needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a grouting blocking method for heat conduction fracture insulation reinforcement of tunnels and a grouting pipe, which can form a permanent heat insulation cylinder layer surrounding the tunnel during the curtain grouting construction process in high geothermal areas, realizing the dual functions of reinforcement and heat insulation, with good heat insulation effect; and there is no need to increase the lining thickness or add a heat insulation layer, reducing the cost.

[0005] The present invention adopts the following technical solutions: A grouting blocking method for heat conduction fracture insulation reinforcement of tunnels, which includes the following steps:

[0006] Step 1: Construct a grout stop wall: Determine the reinforcement range and heat insulation range, where the heat insulation range surrounds the reinforcement range; construct a grout stop wall in front of the heading face, and the outer contour of the grout stop wall is located outside the tunnel excavation contour line;

[0007] Step 2: Reinforcement curtain grouting: On the grout stop wall and within the tunnel excavation contour line, construct reinforcement grouting holes; inject a cement-based grouting material into the surrounding rock through the reinforcement grouting holes;

[0008] Step 3: Construct heat insulation grouting holes: On the grout stop wall and outside the tunnel excavation contour line, construct heat insulation grouting holes, and insert a grouting pipe into the heat insulation grouting holes; the front end of the grouting pipe is located at the bottom of the heat insulation grouting hole; the grouting pipe is a pipe body with both ends open, and the inside of the pipe body is a flow channel for heat insulation composite slurry;

[0009] Step 4. Grouting of the heat insulation curtain: Inject the heat insulation composite chemical slurry from the rear end of the grouting pipe, and let it flow to the front end. At the same time, introduce air into the front end of the grouting pipe to mix with the heat insulation composite chemical slurry, forming a heat insulation composite chemical slurry containing enclosed gas and injecting it into the surrounding rock for solidification.

[0010] Further, the grouting pipe is composed of a pipe head and a pipe body connected front and back; the pipe body is a pipe, which is arranged in the grouting hole until the bottom, and the end inserted into the grouting hole is the front end;

[0011] The pipe head is a frustum-shaped shell with a small head at the front end and a large head at the rear end, and the front end is open; an opening is coaxially arranged on the rear end shell with the front end; the size of the opening is the same as that of the front open end; an equal-length bubble refiner is coaxially arranged on the pipe head. The bubble refiner is a cylindrical bubble stone with openings at both the front and rear ends, and a variable-diameter annular cavity is formed between it and the pipe head;

[0012] An inner pipe is coaxially arranged inside the grouting pipe and attached to one side wall. The front end opening of the inner pipe is located in the annular cavity, and the inner pipe is used to introduce gas into the annular cavity;

[0013] During grouting, the heat insulation composite chemical slurry in the pipe body flows into the inner cavity of the bubble refiner; at the same time, air is pumped into the rear end of the inner pipe. The air enters the annular cavity and is refined into tiny bubbles by the bubble refiner, mixing into the composite chemical slurry flowing to the bubble refiner, forming a composite chemical slurry containing bubbles, flowing out from the front end of the pipe head, and injecting into the surrounding rock;

[0014] Further, a steel mesh is arranged in the grout stop wall, and the steel mesh is parallel to the face of the tunnel heading. The steel mesh is used to improve the tensile and flexural strength of the grout stop wall.

[0015] Further, multiple heat insulation grouting holes are arranged in the area outside the excavation outline line and are located on multiple circumferences spaced radially with the tunnel axis as the center. There are multiple heat insulation grouting holes on the same circumference, and they are arranged at intervals.

[0016] Further, the rear end of the pipe body is threadedly installed with a pipe tail. The pipe tail is a tubular shell with openings at both ends. A through hole is opened on the side wall of the pipe tail, and the inner pipe turns and inserts into the pipe body through the through hole.

[0017] Further, the diameter of the inner pipe is 3 - 5 mm.

[0018] Further, the reinforcement grouting holes are arranged in the area inside the excavation outline line and are located on multiple circumferences spaced radially with the tunnel axis as the center. There are multiple reinforcement grouting holes on the same circumference, and they are arranged at intervals.

[0019] The present invention also discloses a grouting pipe for the above-mentioned tunneling heat-conduction fracture heat-insulation reinforcement grouting blocking method, including: a pipe head, a pipe body, a pipe tail, an inner pipe, and a bubble refiner, where:

[0020] The pipe body is a pipe, which is arranged in the grouting hole until the bottom, and the end inserted into the grouting hole is the front end;

[0021] The pipe head is installed at the front end of the pipe body. It is a frustum-shaped shell with a small head at the front end and a large head at the rear end, and the front end is open. An opening is coaxially provided on the rear-end shell and is coaxial with the front end. A bubble refiner is coaxially arranged in the pipe head. The bubble refiner is a cylindrical bubble stone with openings at both the front and the rear. Both ends of the cylinder body are closely attached to the pipe head and are communicated with the pipe body. A variable-diameter annular cavity is formed between the inner wall of the pipe head. Gas is introduced into the annular cavity. The bubble refiner is used to refine the gas and introduce the gas into its inner cavity;

[0022] The inner pipe is a thin pipe body, which penetrates into the pipe body and is attached to one side inside the pipe body. It is located in the annular cavity and is used to introduce gas into the annular cavity;

[0023] The pipe tail is a tubular shell with openings at both ends. A through hole is provided on the side wall of the pipe tail, and the inner pipe turns and inserts into the pipe body through the through hole.

[0024] The beneficial effects of the present invention are as follows: 1. A composite chemical slurry is selected to form a grouting reinforcement area with good mechanical properties. Outside the surrounding rock reinforcement area, a permanent cylindrical heat-insulation layer is formed by using a heat-insulation material with good heat-insulation performance and poor strength, realizing the dual functions of reinforcement and heat insulation; and by using composite chemical slurry grouting, there is no need to increase the lining thickness or add a heat-insulation layer, and the cost is low. 2. First, cement-based material reinforcement grouting is carried out, and then heat-insulation material grouting is carried out, avoiding the injection of heat-insulation materials with poor strength into the reinforcement area and not reducing the strength of the surrounding rock in the reinforcement area. 3. A steel mesh is arranged in the grout stop wall, and after the grout stop wall is consolidated, good sealing and crack resistance performance are achieved. 4. The grouting pipe in the method for heat-insulation grouting blocking of heat-conduction fracture layer in high-geothermal tunnels is selected for grouting. A bubble refiner is coaxially arranged in the pipe head. A variable-diameter annular cavity is formed between the bubble refiner and the pipe head. During grouting, gas is introduced into the annular cavity and enters the inner part through the side wall of the bubble refiner and is mixed with the slurry to obtain a slurry containing closed bubbles. This slurry is used as a heat-insulation material, and after solidification, it is full of voids inside, and the heat-insulation effect is good. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the heat-insulation grouting hole in the pipe for the tunneling heat-conduction fracture heat-insulation reinforcement grouting blocking method;

[0026] Figure 2 It is a schematic diagram of gas mixing in the pipe head of the heat-insulation grouting hole in the tunneling heat-conduction fracture heat-insulation reinforcement grouting blocking method;

[0027] Figure 3 It is a sectional view of the pipe head of the heat insulation grouting hole in the heat insulation reinforcement grouting blocking method for tunnel heat conduction fracture;

[0028] Figure 4 It is a schematic diagram of the design scheme for heat insulation reinforcement grouting blocking of tunnel heat conduction fracture;

[0029] Wherein: 1. Reinforcement grouting hole; 2. Heat insulation grouting hole; 3. Grout stop wall;

[0030] 21. Pipe head; 22. Pipe body; 23. Joint; 24. Pipe tail; 25. Air pipe; 26. Bubble refiner. Specific implementation manner

[0031] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0032] The heat insulation reinforcement grouting blocking method for tunnel heat conduction fracture of the present invention includes the following steps:

[0033] Step 1. The heat insulation reinforcement grouting blocking method for the heat conduction fracture layer of high geothermal tunnels is characterized in that the method includes the following steps:

[0034] Step 1. Construct the grout stop wall 3: Determine the reinforcement range and heat insulation range, wherein the heat insulation range surrounds the reinforcement range. The reinforcement range is calculated based on the initial and final values of the surrounding rock mechanical parameters so that the surrounding rock can reach structural stability. Measure the initial thermal conductivity of the surrounding rock, and calculate the thermal conductivity after reinforcement, determine the heat dissipation of the surrounding rock after reinforcement. When there is no heat insulation range set, calculate the heat conduction to the tunnel internal environment temperature. According to the tunnel construction requirements, there is a temperature design value for the tunnel construction environment, then the required heat insulation range can be calculated.

[0035] Construct the grout stop wall 3 in front of the heading face, and the outer contour of the grout stop wall 3 is located outside the tunnel excavation contour line; wherein, the distance between the outer contour line and the excavation contour line is 3 - 5m, and the area between the outer contour line and the excavation contour line is used as the area for constructing the heat insulation grouting hole 2.

[0036] The radial area of the grout stop wall is large, and multiple holes are drilled in the grout stop wall later. To improve the tensile and flexural strength of the grout stop wall and avoid its own cracking during drilling. A steel mesh is arranged in the grout stop wall 3, and the steel mesh is parallel to the heading face, and the grout stop wall is constructed by pouring fine-grained concrete and vibrated thoroughly.

[0037] During grouting, first carry out cement-based material reinforcement grouting, and then carry out heat insulation material grouting to avoid injecting heat insulation materials with poor strength into the reinforcement area, reducing the strength of the surrounding rock in the reinforcement area and affecting the excavation safety.

[0038] Step 2: Reinforcement curtain grouting: On the grout stop wall 3 and within the tunnel excavation contour line, construction of reinforcement grouting holes 1 is carried out, and the end holes are located in the reinforcement area, that is, surrounding the tunnel curtain for one week. Cement-based grouting materials are injected into the surrounding rock through the reinforcement grouting holes 1 to play the role of reinforcing the surrounding rock. There are multiple reinforcement grouting holes 1. The specific settings are as follows: They are set in the area within the excavation contour line and are located on multiple circumferences spaced in the radial direction with the tunnel axis as the center. There are multiple reinforcement grouting holes 1 on the same circumference and they are arranged at intervals. As Figure 1 shown, specifically, the number and diameter of the reinforcement grouting holes 1 are both calculated according to the characteristics of the surrounding rock and the ultimately achieved reinforcement strength. After grouting reinforcement, the mechanical properties of the surrounding rock are improved to ensure the safety of the excavation construction.

[0039] Step 3: Construction of heat insulation grouting holes (2): On the grout stop wall 3 and outside the tunnel excavation contour line, construction of heat insulation grouting holes 2 is carried out. Grouting pipes are inserted into the heat insulation grouting holes 2. Multiple heat insulation grouting holes 2 are set in the area outside the excavation contour line and are located on multiple circumferences spaced in the radial direction with the tunnel axis as the center. There are multiple heat insulation grouting holes 2 on the same circumference and they are arranged at intervals.

[0040] As Figure 2 、 3 and Figure 4 show, the present invention also discloses a grouting pipe used in the method for heat conduction fracture heat insulation reinforcement grouting interruption in tunnels. The grouting pipe includes: a pipe head 21, a pipe body 22,, an inner pipe 25 and a bubble refiner 26. The pipe head (21), the pipe body (22), the joint (23) and the pipe tail (24) are all made of PVC material.

[0041] Among them:

[0042] The pipe body 22 is a pipe body, which is composed of multiple pipe segments connected in sequence. External threads are provided at the ends of each segment; the segments are connected by a joint 23. The joint is a pipe body with internal threads provided at both ends and is threadedly connected to the pipe segments at both ends. The pipe body 22 is arranged in the heat insulation grouting hole 2 until the bottom, and the end inserted into the heat insulation grouting hole 2 is the front end; the pipe head 21 is installed at the front end of the pipe body 22 and is a frustum-shaped shell with a small head at the front end and a large head at the rear end, and the front end is an open shape. An opening is coaxially provided on the rear end shell with the front end; the size of the opening is the same as the size of the front end opening; a bubble refiner 26 is coaxially arranged in the pipe head 21. The bubble refiner 26 is a cylindrical bubble stone with openings at both the front and the rear. The front and rear ends of the cylinder are closely attached to the pipe head 21. A variable-diameter annular channel is formed between the bubble refiner 26 and the pipe head 21.

[0043] The inner tube 25 is inserted into the tube body 22 and placed against the inner wall on one side of the tube body 22; it is inserted into the tube body 22 and against the inner side within the tube body 22; its front end is located within the annular channel, and the inner tube 25 is used to introduce gas into the annular channel; the diameter of the inner tube 25 is 3 - 5 mm, so that the amount of gas flowing out from the front end is suitable for pumping the slurry and keeps the flowing gas at a certain pressure. Specifically, a through hole can be axially opened on the rear housing of the tube head 21 so that the front end of the inner tube 25 penetrates into the annular channel. The tube tail 24 is a tubular housing with both ends open and is threadedly installed at the rear end of the tube body 22. A through hole is opened on the housing of the tube tail 24, and the through hole is for the entrance where the inner tube 25 penetrates into the tube body 22.

[0044] Step Four: Heat-insulating curtain grouting: Use composite chemical slurry for grouting. The slurry is made by mixing polyurethane, epoxy resin, and surfactant in a ratio of 9.5:1:0.5, with good fluidity and large surface tension. Inject the composite chemical slurry into the tube body 22 from the rear end of the tube tail 24 and flow to the bubble refiner 26; meanwhile, pump air into the rear end of the inner tube 25, enter the annular channel, and be refined into tiny bubbles by the bubble refiner 26 at the front end, and mix into the composite chemical slurry flowing to the bubble refiner 26 to form a composite chemical slurry saturated with bubbles. Then it continues to flow and flows out from the front end of the tube head 21 and is injected into the surrounding rock. After solidification, the slurry forms a slurry body with closed bubbles inside. Eventually, a structure of an outer cylindrical heat-insulating layer surrounding and reinforcing layer is formed within the surrounding rock, achieving the dual functions of reinforcement and heat insulation. Due to the presence of bubbles, it plays a role in storing gas and preventing rapid heat conduction. Coupled with the fact that the selected composite chemical slurry itself is a material with heat-insulating properties, the heat-insulating effect is better after solidification within the surrounding rock.

[0045] Inject composite chemical slurry for grouting within the surrounding rock, combine with the surrounding rock to form a structure of a heat-insulating layer surrounding and reinforcing layer, without the need for additional construction to add a thermal insulation layer, nor the need to increase the thickness of the lining. Moreover, during the tunnel construction process, high-power ventilation is not required, reducing the construction cost.

Claims

1. A grouting blocking method for thermal conductive fracture insulation reinforcement in tunnels, characterized in that, The method includes the following steps: Step 1, constructing a grout stopping wall (3): determining the reinforcement range and the heat insulation range, wherein the heat insulation range surrounds the reinforcement range; constructing the grout stopping wall (3) in front of the heading face, and the outer contour of the grout stopping wall (3) is located outside the tunnel excavation contour line; Step 2, reinforcement curtain grouting: constructing reinforcement grouting holes (1) on the grout stopping wall (3) and within the tunnel excavation contour line; injecting a cement-based grouting material into the surrounding rock through the reinforcement grouting holes (1); Step 3, constructing heat insulation grouting holes (2): constructing heat insulation grouting holes (2) on the grout stopping wall (3) and outside the tunnel excavation contour line, inserting a grouting pipe into the heat insulation grouting holes (2); the front end of the grouting pipe is located at the bottom of the heat insulation grouting hole (2); the grouting pipe is a pipe body with openings at both ends, and the inside of the pipe body is a flow channel for the heat insulation composite slurry; Step 4, heat insulation curtain grouting: injecting the heat insulation composite chemical slurry from the rear end of the grouting pipe, flowing to the front end, and at the same time, introducing air into the front end of the grouting pipe to mix with the heat insulation composite chemical slurry, forming a heat insulation composite chemical slurry saturated with enclosed gas and injecting it into the surrounding rock to solidify; The grouting pipe is composed of a pipe head (21) and a pipe body (22) connected front and back; the pipe body (22) is a pipe body, which is arranged in the grouting hole (2) until the bottom, and the end inserted into the grouting hole (2) is the front end; The pipe head (21) is a frustum-shaped shell with a small head at the front end and a large head at the rear end, and the front end is open, and an opening is coaxially opened on the rear end shell with the front end; the size of the opening is the same as that of the front end opening; an equi-length bubble refiner (26) is coaxially arranged on the pipe head (21), and the bubble refiner (26) is a cylindrical bubble stone with openings at both ends, forming a reduced-diameter annular cavity with the pipe head (21); An inner pipe (25) is coaxially arranged on one side wall inside the grouting pipe, and the front end opening of the inner pipe (25) is located in the annular cavity, and the inner pipe (25) is used to introduce gas into the annular cavity; During grouting, the heat insulation composite chemical slurry in the pipe body (22) flows into the inner cavity of the bubble refiner (26); at the same time, air is pumped into the rear end of the inner pipe (25), the air enters the annular cavity, is refined into tiny bubbles by the bubble refiner (26), and is mixed into the composite chemical slurry flowing to the bubble refiner (26), forming a composite chemical slurry saturated with bubbles, flowing out from the front end of the pipe head (21) and injecting it into the surrounding rock.

2. The tunnel heat-conducting fracture heat insulation reinforcement grouting blocking method according to claim 1, wherein A steel bar mesh is arranged in the grout stopping wall (3), and the steel bar mesh is parallel to the heading face, and the steel bar mesh is used to improve the tensile and flexural strength of the grout stopping wall.

3. The tunnel heat conduction fracture heat insulation reinforcement grouting blocking method according to claim 2, wherein, A plurality of the heat insulation grouting holes (2) are arranged in the area outside the excavation contour line and are located on a plurality of circumferences spaced apart in the radial direction with the tunnel axis as the center. There are a plurality of heat insulation grouting holes (2) on the same circumference, and they are spaced apart.

4. The grouting blocking method for tunnel heat-conducting fracture heat insulation reinforcement according to claim 3, characterized in that The rear end of the pipe body (22) is threadedly installed with a pipe tail (24), the pipe tail (24) is a tubular shell with openings at both ends, and through holes are opened on the side wall of the pipe tail (24), and the inner pipe (25) is inserted into the pipe body (22) through the through holes after turning.

5. The method for heat conduction fracture insulation reinforcement grouting blocking in a tunnel according to claim 4, characterized in that The diameter of the inner tube (25) is 3 to 5 mm.

6. The method for heat conduction fracture heat insulation reinforcement grouting blocking in a tunnel according to claim 5, characterized in that, The reinforcement grouting holes (1) are arranged in the area within the excavation contour line and are located on a plurality of circumferences spaced radially with the tunnel axis as the center. There are a plurality of reinforcement grouting holes (1) on the same circumference, and they are arranged at intervals.

7. The grouting pipe for the grouting interruption method of tunnel heat-conducting fracture heat insulation reinforcement according to any one of claims 1-6, characterized in that, Comprising: A pipe head (21), a pipe body (22), a pipe tail (24), an inner tube (25) and a bubble refiner (26), wherein: The pipe body (22) is a pipe body and is arranged in the grouting hole (2) until the bottom. The end inserted into the grouting hole (2) is the front end. The pipe head (21) is installed at the front end of the pipe body (22) and is a frustum-shaped shell with a small head at the front end and a large head at the rear end. The front end is an open shape, and an opening is coaxially provided on the rear end shell with the front end. A bubble refiner (26) is coaxially arranged in the pipe head (21). The bubble refiner (26) is a cylindrical bubble stone with openings at both the front and the rear. Both ends of the cylinder body are closely attached to the pipe head (21) and are connected to the pipe body (22). A variable-diameter annular cavity is formed between the inner wall of the pipe head (21). Gas is introduced into the annular cavity. The bubble refiner (26) is used to refine the gas and introduce the gas into its inner cavity. The inner tube (25) is a thin tube body, penetrates into the pipe body (22), and is attached to one side inside the pipe body (22). Located in the annular cavity, the inner tube (25) is used to introduce gas into the annular cavity. The pipe tail (24) is a tubular shell with openings at both ends. A through hole is provided on the side wall of the pipe tail (24). The inner tube (25) turns through the through hole and is inserted into the pipe body (22).

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