Inhaul cable opposite arch type reinforcing structure in tunnel and construction method of inhaul cable opposite arch type reinforcing structure

Abstract

The invention discloses an inhaul cable opposite-arch type reinforcing structure in a tunnel and a construction method of the inhaul cable opposite-arch type reinforcing structure. The reinforcing structure comprises a tunnel primary supporting structure, inclined upward anchor cables are arranged on the outer sides of side walls on the two sides of the tunnel primary supporting structure, a vertical grouting pipe is arranged below an inverted arch at the bottom of the tunnel primary supporting structure, a slurry soil layer composite reinforcing structure is arranged on the periphery of the grouting pipe, and the upper end of the grouting pipe is fixedly connected with the inverted arch; the upper ends of the grouting pipes arranged transversely and the grout soil layer composite reinforcing structure form an inverted arch matched with the inverted arch, and the lower ends of the grouting pipes arranged transversely and the grout soil layer composite reinforcing structure form a regular arch. The construction method comprises the steps of construction preparation; constructing an arch wall; constructing an inverted arch; grouting pipe construction; anchor cable construction; and secondary lining construction. The construction method has the beneficial effects that the overall strength of a soil body is improved through the grouting steel floral tubes; the steel pipe pile foundation can form an arch structure and has extremely high mechanical property; the lining structure of the tunnel and the deep surrounding rocks on the two sides can be connected through the arrangement of the anchor cables.

Description

Technical Field

[0001] The present application belongs to the technical field of building tunnel construction, and specifically relates to a cable-arch reinforcement structure in a tunnel and a construction method thereof. Background Art

[0002] During the tunnel construction process, karst caves and culverts are a common geological problem, which may lead to uneven settlement of the tunnel base and even serious consequences such as structural instability, affecting the safety, stability and bearing capacity of the tunnel structure.

[0003] In the prior art, low-grade concrete filling, pile foundation and other methods are usually used. Such methods are highly dependent on the distribution and shape of the caves, and have limited effects on non-continuously developed caves or culverts. The filling volume is large and the cost is high. The most important thing is that the filling affects the circulation of the original water system in the culvert, which can easily increase the water pressure at the bottom of the tunnel and cause the arch to rise. The pile foundation method is to transfer the load to the deep stable stratum by setting up deep foundation structures such as cast-in-place piles, but this method has high construction costs, slow progress, and is limited by the location of underground caves and culverts.

[0004] Traditional methods have limitations in dealing with such problems and are unable to meet the requirements of modern tunnel engineering for overall bearing capacity and stability. Summary of the invention

[0005] The purpose of the present application is to provide a cable-stayed arch reinforcement structure in a tunnel and a construction method thereof, wherein a steel flower pipe grouting is arranged in the soft foundation of the tunnel base, and after grouting, the steel pipe acts as a steel pipe pile foundation, and the surrounding rock reinforced by grouting forms two upper and lower arch structures, and the arch structures are connected to form a whole through the grouting steel pipes in the surrounding rock, and the upper arch structure coincides with the tunnel lining line to form an inverted arch reinforcement structure, and anchor cables are applied on both sides of the upper inverted arch structure to form cables for the arch structure, and the lower arch structure forms a solid arch positive arch reinforcement structure, and an inverted arch lining structure is applied on the upper arch structure, which solves the above-mentioned problems and meets the actual needs of modern tunnel engineering.

[0006] The purpose of this application is achieved through the following technical solutions: A cable-stayed arch reinforcement structure in a tunnel comprises a tunnel primary support structure, the outer sides of the side walls on both sides of the tunnel primary support structure are provided with inclined upward anchor cables, a vertical grouting pipe is provided below the inverted arch at the bottom of the tunnel primary support structure, a slurry-soil layer composite reinforcement structure is provided on the outer periphery of the grouting pipe, the upper end of the grouting pipe is fixedly connected to the inverted arch, the upper end of the grouting pipe arranged along the transverse direction and the slurry-soil layer composite reinforcement structure form an inverted arch shape that matches the inverted arch, and the lower end of the grouting pipe arranged along the transverse direction and the slurry-soil layer composite reinforcement structure form a positive arch shape.

[0007] Furthermore, the tunnel primary support structure includes primary support concrete and primary support arches in the primary support concrete.

[0008] Furthermore, a tunnel secondary lining structure is constructed on the inner side of the primary support structure of the tunnel.

[0009] Furthermore, the tunnel primary support structure has a plurality of anchor cables arranged at intervals along the longitudinal direction, and three anchor cables of each anchor cable are arranged vertically on the outer sides of the side walls on both sides.

[0010] Furthermore, the grouting pipe is a steel flower pipe, a plurality of grouting holes are opened on the outer wall of the steel flower pipe, and the lower end of the steel flower pipe is a closed tip.

[0011] Furthermore, the upper end of the grouting pipe is fixed to the primary support arch of the tunnel primary support structure through U-shaped stirrups.

[0012] Furthermore, a bite area is formed between adjacent slurry-soil layer composite reinforcement structures.

[0013] A construction method for a cable-arch reinforcement structure in a tunnel comprises the following steps: Step 1, construction preparation; Step 2, arch wall construction: excavation and support of tunnel arch wall; Step 3, invert construction: excavation and support of the invert at the bottom of the tunnel; Step 4, grouting pipe construction: grouting pipe operation is performed below the inverted arch at the bottom of the tunnel, the upper end of the grouting pipe arranged in the transverse direction is maintained to form an inverted arch shape that matches the inverted arch, the lower end of the grouting pipe arranged in the transverse direction is maintained to form a positive arch shape, and grouting is performed on the periphery of the grouting pipe to form a slurry-soil composite reinforcement structure; Step 5, anchor cable construction: anchor cables are anchored on the outside of the side walls on both sides of the tunnel, and the anchor cables are arranged obliquely upward; Step 6, Secondary lining construction: Carry out secondary lining work on the tunnel arch wall and the inner side of the tunnel invert.

[0014] Furthermore, step 2 also includes determining the geological distribution: while the arch wall excavation and support operations are being carried out, the location, burial depth, direction and distribution of the caves and culverts in the area below the base of the tunnel invert are further explored.

[0015] Furthermore, in the step 4, a hole is drilled below the tunnel invert, a grouting pipe is lowered into the hole, and reinforcement slurry is injected into the surrounding soil layer through the grouting pipe. The slurry and the soil layer are mixed to form a slurry-soil composite reinforcement structure, and then the upper end of the grouting pipe is fixed to the tunnel invert.

[0016] Beneficial effects of this application: 1. The length of the grouting steel pipe can be flexibly designed according to the strength of the surrounding rock at the base, the distribution of caves and culverts. The slurry can fill the cracks and pores of the surrounding rock at the base of the tunnel, improve the overall strength of the soil, form a solid waterproof barrier, and effectively prevent water penetration. Steel pipe pile foundations of different lengths can form an arch structure, directly spanning the cave or culvert, reducing the impact on the groundwater system. At the same time, the arch structure has extremely strong mechanical properties, which can disperse and transmit the pressure from the tunnel structure and the surrounding rock above, and the force is evenly distributed, so that the load will not be concentrated in a specific area, reducing the impact of the deformation of the surrounding rock below the arch structure on the tunnel structure, and greatly improving the stability of the tunnel structure.

[0017] 2. Arch force transmission: The arch structure naturally has a strong bearing capacity and can effectively disperse the pressure from the tunnel load. The upper and lower arch structures form two parts, the reverse arch and the positive arch. The synergy of the upper and lower arch structures enables the tunnel load to be transmitted through different paths and methods. The arch structure can transmit pressure through the arch ribs and disperse local stress, thereby avoiding excessive or uneven settlement of the tunnel base. The design of the reverse arch and the positive arch allows the overall structure to be supported in different directions, improving the anti-deformation ability. The combination of the upper arch structure and the lower arch structure can effectively share and transmit the pressure of the upper tunnel structure. At the same time, the lower arch structure reduces the demand for the bearing capacity of the lower surrounding rock, eliminates the influence of insufficient bearing capacity caused by the existence of caves or culverts, and resists the scouring and erosion of the culvert water flow and the influence of water pressure. The design of the upper and lower arch structures can play a role in a variety of geological conditions, especially in areas with developed caves and culverts. The arch structure can form a self-balancing system, reduce the disturbance to the original geological structure, and effectively reduce the structural deformation caused by geological unevenness. The design of the arch structure enables the steel pipe pile foundation to play the role of reinforcing the surrounding rock and transmitting force in the soft foundation of the tunnel, and can better deal with problems such as settlement and deformation that may exist in the soft foundation.

[0018] 3. Avoid stress concentration and uneven settlement. In traditional reinforcement design, the base reinforcement piles are usually evenly arranged. However, if there are caves or culverts underground, the evenly arranged pile foundations may not be able to effectively support the pressure in different areas, resulting in stress concentration and local settlement problems. At the same time, it will also damage the original underground culverts, change the direction or size of the water flow channel, and may cause the water pressure at the base of the tunnel to increase, resulting in the uplift of the invert. The design of steel pipes of different lengths can adjust the length and distribution density of the steel pipes according to different geological conditions and cave distribution, thereby effectively avoiding stress concentration and disturbance to the original stratum structure, and ensuring the consistency of overall settlement.

[0019] 4. The design of the arch structure naturally has stronger bearing capacity and seismic resistance, and can effectively disperse vibration and stress under external forces such as earthquakes, making the structural deformation more uniform and enhancing overall stability. The upper and lower arch structures work together to quickly disperse the load and vibration to a larger area through the arch ribs when the tunnel and its surrounding environment are displaced or subjected to external forces, thereby reducing the risk of local damage.

[0020] 5. The setting of anchor cables can connect the tunnel lining structure with the deep surrounding rock on both sides, which can offset part of the pressure of the arch wall surrounding rock into the tunnel and downward, as well as part of the deadweight pressure of the lining structure, improve the stability of the tunnel structure, reduce the tunnel structure's demand for base bearing capacity, and greatly reduce the impact of uneven settlement caused by caves or culverts on the tunnel structure.

[0021] The aforementioned main scheme of the present application and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection in the present application; and in the present application, (non-conflicting options) can also be freely combined with each other and with other options. After understanding the scheme of the present application, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present application, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of the cross section of this application.

[0023] Figure 2 It is a structural schematic diagram of the longitudinal section of this application.

[0024] Figure 3 It is a schematic diagram of the connection structure between the grouting pipe and the primary support arch frame of the present application.

[0025] Figure 4 It is a structural schematic diagram of the grouting pipe of the present application.

[0026] In the figure: 1- tunnel primary support structure, 101- side wall, 102- invert arch, 103- primary support arch frame, 2- tunnel secondary lining structure, 3- anchor cable, 4- grouting pipe, 401- U-shaped stirrup, 402- grouting hole, 403- closed tip. DETAILED DESCRIPTION

[0027] The following non-limiting examples are provided to illustrate the present application.

[0028] Example 1 refer to Figure 1~Figure 4 As shown, a cable-arch reinforcement structure in a tunnel includes a tunnel primary support structure 1, a tunnel secondary lining structure 2, anchor cables 3 and a grouting pipe 4.

[0029] The outer sides of the side walls 101 on both sides of the primary support structure 1 of the tunnel are all provided with inclined upward anchor cables 3. The anchor cables 3 are respectively driven to both sides at the lower position of the side walls 101. The anchor cables 3 are arranged along the tunnel travel direction. The number, length and longitudinal arrangement spacing of the anchor cables arranged in each section are determined according to design calculations or test data. The setting of the anchor cables can connect the lining structure of the tunnel with the deep surrounding rock, offset part of the pressure of the arch wall surrounding rock into the tunnel and downward, and part of the deadweight pressure of the lining structure, improve the stability of the tunnel structure, and greatly reduce the influence of uneven settlement caused by caves or culverts on the tunnel structure.

[0030] A vertical grouting pipe 4 is constructed below the inverted arch 102 at the bottom of the tunnel primary support structure 1. The upper end of the grouting pipe 4 is fixedly connected to the inverted arch 102. The grouting pipe 4 is used as a casing for grouting and also as a branch pipe for reinforcement. A slurry soil layer composite reinforcement structure is constructed on the periphery of the grouting pipe 4. The upper end of the grouting pipe 4 and the slurry soil layer composite reinforcement structure arranged in the transverse direction form an inverted arch that matches the inverted arch 102. The upper arch structure matches the tunnel lining line. The inverted arch structure has the characteristic of arc-shaped load-bearing, has a strong load-bearing capacity, can withstand a large load, can not only enhance the anti-deformation ability of the tunnel lining, but also can disperse the stress around the tunnel lining through a reasonable arch design, thereby improving the safety of the tunnel structure.

[0031] The composite reinforcement structure of the grouting layer at the lower end of the grouting pipe 4 arranged in the transverse direction forms a positive arch. The lower arch structure adopts a solid arch design to form a positive arch reinforcement structure. The arch structure plays a supporting role in the tunnel base, enhances the bearing capacity of the base, and effectively isolates the influence of the cave and the dark channel area. At the same time, it will not change the original water flow channel of the dark channel, eliminating the possibility of increased water pressure in the tunnel base due to human factors. The shape and size of the lower arch structure are designed according to the specific distribution of the cave and the dark channel. The stability of the tunnel bottom is ensured through a reasonable structural form. At the same time, the grouting technology injects slurry into the cracks and pores of the surrounding rock. After the slurry solidifies, the overall strength of the soil is improved, forming a solid waterproof barrier, effectively preventing water penetration, and preventing the potential hazards caused by dark channel scouring and karst caves.

[0032] The tunnel primary support structure 1 includes side walls on both sides, an inverted arch at the bottom and an arc top at the top, specifically including primary support concrete and a primary support arch frame 103 in the primary support concrete. At the same time, a tunnel secondary lining structure 2 is constructed inside the tunnel primary support structure 1 to enhance the bearing capacity and earthquake resistance of the tunnel, and also has waterproof and heat insulation functions.

[0033] The tunnel primary support structure 1 is provided with a plurality of anchor cables 3 arranged at intervals along the longitudinal direction, and three anchor cables 3 are arranged vertically on the outer sides of the side walls 101 on both sides to ensure the anchoring effect of the anchor cables 3 .

[0034] The grouting pipe 4 is a steel pipe with an opening at the upper end for injection of slurry. The outer wall of the steel pipe is provided with a plurality of grouting holes 402, from which the slurry can be ejected into the soil layer. The lower end of the steel pipe is a closed tip 403, which facilitates the downward insertion of the pipe and prevents the slurry from leaking from the bottom.

[0035] The steel flower pipe is constructed along the primary support steel arch frame of the tunnel invert. The upper end of the grouting pipe 4 is fixed to the primary support arch frame 103 of the tunnel primary support structure 1 by U-shaped stirrups 401. The fixation can be achieved by welding. The length, spacing, diameter and other parameters of the steel flower pipe are optimized according to the on-site geological conditions. An interlocking area is formed between adjacent slurry soil layer composite reinforcement structures. The surrounding rock of the grouting reinforcement area presents two upper and lower arch structures. The steel pipe pile foundation acts as a tie rod. The grouting area between adjacent steel pipes is interlocked to connect the upper and lower arch structures to form a complete whole.

[0036] Example 2 refer to Figure 1~Figure 4 As shown, a construction method for a cable-stayed arch type reinforcement structure in a tunnel, to construct the cable-stayed arch type reinforcement structure in a tunnel of Example 1, comprises the following steps: Step 1, construction preparation: including surveying and laying out, and advanced geological prediction.

[0037] Step 2, arch wall construction: According to the design requirements and combined with the on-site geological conditions, the tunnel arch wall (including the side wall 101 and the arc top) is excavated and supported, the primary support arch frame 103 is installed and the primary support concrete is sprayed.

[0038] Determine the geological distribution: While excavating and supporting the arch wall, further explore the location, depth, direction and distribution of caves and culverts in the area below the base of the tunnel arch.

[0039] Step 3, invert construction: excavation and support of the invert 102 at the bottom of the tunnel, installation of the primary support arch frame 103 and spraying of primary support concrete.

[0040] Step 4, grouting pipe construction: according to the location, burial depth, direction and distribution of the base cave and culvert, combined with the bearing capacity requirements of the tunnel base, determine the diameter of the grouting pipe 4, the reasonable arch axis of the layout and the depth of each steel pipe. The grouting pipe 4 is a steel flower pipe, which is processed by hot-rolled seamless steel pipe. The wall thickness, diameter, length and layout spacing of the steel pipe are determined by design calculation or test data.

[0041] A hole is drilled below the tunnel invert, a grouting pipe 4 is placed in the hole, and reinforcing slurry is injected into the peripheral soil layer through the grouting pipe. The slurry and the soil layer are mixed to form a slurry-soil composite reinforcement structure, and then the upper end of the grouting pipe is fixed to the tunnel invert.

[0042] After the arch section is excavated and formed, the arch steel arch frame is installed immediately, followed by the erection of a drilling rig. The grouting reinforcement construction is completed according to the steps of drilling-pipe placement-grouting. The top of the steel pipe is welded and connected to the initial support steel arch frame using U-shaped stirrups to form a whole.

[0043] The grouting pipe operation is carried out below the inverted arch at the bottom of the tunnel. The upper ends of the grouting pipes arranged along the transverse direction are kept to form an inverted arch shape that matches the inverted arch, and the lower ends of the grouting pipes arranged along the transverse direction are kept to form a positive arch shape. Grouting is injected around the periphery of the grouting pipes, and the slurry is mixed with the soil layer to form a slurry-soil composite reinforcement structure.

[0044] Step 5, anchor cable construction: anchor cables 3 are anchored on the outside of the side walls on both sides of the tunnel, and the anchor cables 3 are arranged obliquely upward from the inside to the outside. Three anchor cables are set on the side walls. The length, number of anchor cables, and the size of the applied prestress can be adjusted through design calculations or test data during the actual construction process.

[0045] Step 6, Secondary lining construction: Secondary lining work is carried out on the tunnel arch wall and the inner side of the tunnel invert to complete the reinforcement structure.

[0046] The aforementioned basic examples and their further selected examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection in this application. In the scheme of this application, each selected example can be arbitrarily combined with any other basic examples and selected examples.

[0047] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A cable arch reinforcement structure in a tunnel, comprising a tunnel primary support structure (1), characterized in that: Anchor cables (3) inclined upward are applied on the outer sides of the side walls (101) on both sides of the tunnel primary support structure (1), a vertical grouting pipe (4) is applied below the inverted arch (102) at the bottom of the tunnel primary support structure (1), a slurry soil layer composite reinforcement structure is applied on the outer periphery of the grouting pipe (4), the upper end of the grouting pipe (4) is fixedly connected to the inverted arch (102), the upper end of the grouting pipe (4) and the slurry soil layer composite reinforcement structure arranged in the transverse direction form an inverted arch shape that matches the inverted arch (102), and the slurry soil layer composite reinforcement structure at the lower end of the grouting pipe (4) arranged in the transverse direction forms a positive arch shape.

2. The cable arch reinforcement structure in the tunnel according to claim 1 is characterized in that: The tunnel primary support structure (1) comprises primary support concrete and a primary support arch frame (103) in the primary support concrete.

3. The cable arch reinforcement structure in the tunnel according to claim 1 is characterized in that: A tunnel secondary lining structure (2) is constructed on the inner side of the tunnel primary support structure (1).

4. The cable arch reinforcement structure in the tunnel according to claim 1, characterized in that: The tunnel primary support structure (1) is provided with a plurality of anchor cables (3) arranged at intervals along the longitudinal direction, and three anchor cables (3) are arranged vertically on the outer sides of the side walls (101) on both sides.

5. The cable arch reinforcement structure in the tunnel according to claim 1, characterized in that: The grouting pipe (4) is a steel flower pipe, the outer wall of which is provided with a plurality of grouting holes (402), and the lower end of the steel flower pipe is a closed tip (403).

6. The cable arch reinforcement structure in a tunnel according to claim 1 or 5, characterized in that: The upper end of the grouting pipe (4) is fixed to the primary support arch (103) of the tunnel primary support structure (1) via a U-shaped stirrup (401).

7. The cable arch reinforcement structure in the tunnel according to claim 1, characterized in that: A bite area is formed between adjacent slurry-soil layer composite reinforcement structures.

8. A construction method for a cable arch reinforcement structure in a tunnel, characterized in that: The steps include: Step 1, construction preparation; Step 2, arch wall construction: excavation and support of tunnel arch wall; Step 3, invert construction: excavation and support of the invert at the bottom of the tunnel; Step 4, grouting pipe construction: grouting pipe operation is performed below the inverted arch at the bottom of the tunnel, the upper end of the grouting pipe arranged in the transverse direction is maintained to form an inverted arch shape that matches the inverted arch, the lower end of the grouting pipe arranged in the transverse direction is maintained to form a positive arch shape, and grouting is performed on the periphery of the grouting pipe to form a slurry-soil composite reinforcement structure; Step 5, anchor cable construction: anchoring the anchor cables (3) on the outside of the side walls on both sides of the tunnel, keeping the anchor cables (3) arranged obliquely upward; Step 6, Secondary lining construction: Carry out secondary lining work on the tunnel arch wall and the inner side of the tunnel invert.

9. The construction method of the cable arch reinforcement structure in the tunnel according to claim 8, characterized in that: Step 2 also includes determining the geological distribution: while the arch wall excavation and support operations are being carried out, the location, burial depth, direction and distribution of caves and culverts in the area below the base of the tunnel invert are further explored.

10. The construction method of the cable arch reinforcement structure in a tunnel according to claim 8 or 9, characterized in that: In step 4, a hole is drilled below the tunnel invert, a grouting pipe is placed in the hole, and reinforcing slurry is injected into the surrounding soil layer through the grouting pipe. The slurry and the soil layer are mixed to form a slurry-soil layer composite reinforcement structure, and then the upper end of the grouting pipe is fixed to the tunnel invert.

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