Tunneling through cave combined detour gallery structure and construction method

Abstract

The application provides a tunneling cave bypassing cave permanent and temporary combined detour structure and construction method, and belongs to the technical field of tunnel engineering. The structure comprises a bypassing cave which is communicated with a starting section at one end, and the other end of the bypassing cave extends to a terminal section after passing through the upstream of a cave, and a tunnel bottom box culvert which is communicated with the bypassing cave is arranged in the terminal section, the other end of the tunnel bottom box culvert is communicated with the downstream of the cave, a water passing hole is arranged on the side of the bypassing cave which faces the upstream of the cave, and a blocking part is arranged in the bypassing cave between the upstream of the cave and the starting section. The bypassing cave is arranged outside the cave as a temporary construction passage, a front tunnel construction working surface is opened, the interference between tunnel construction and cave exploration and treatment is reduced, the tunnel is ensured to be constructed safely and continuously, the construction period is ensured, the bypassing cave is used as a permanent drainage passage in the later period, the effective utilization of the project is ensured, the investment is reduced, the tunnel operation safety is ensured, and the structure has great practical significance and economic value.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering technology and relates to a meandering tunnel structure and construction method that combines permanent and temporary tunnels through karst caves. Background Technology

[0002] When tunnel construction uncovers complex karst caves, it is necessary to re-examine the cave interior and the surface, and conduct hydrological observations for an extended period before a treatment plan can be determined. The entire process is time-consuming, and construction must continue due to the project's established schedule. Therefore, how to quickly and safely traverse karst caves, minimize interference between karst cave exploration and treatment and the continued tunnel construction, and ensure the tunnel's scheduled completion time and the safety and reliability of the karst cave section remain pressing engineering problems that need to be solved.

[0003] When exposing complex karst caves during existing tunnel construction, the following three methods are used: Method 1: Based solely on the existing surface phenomena of the karst cave, existing technologies (such as adding arch supports, temporary backfilling, or strengthening initial support) are used for rapid passage. However, this method lacks detailed investigation of the karst cave, especially the hydraulic connections within it. Because karst caves involve karst water in addition to their own cavities, they are often initially dry caves, but during the rainy season, large amounts of water may suddenly appear inside. Therefore, this method faces significant safety hazards. Method 2: A new investigation and hydrological observation are conducted according to the prescribed procedures for karst cave treatment before a plan is developed. The first method, while ensuring the structural safety of the tunnel crossing the karst cave section, introduces a risk to the construction schedule, potentially affecting the overall project completion time. The third method involves constructing a temporary detour tunnel in front of the karst cave to continue construction. While this method solves the problem of continuing construction and addresses the safety of the karst cave section, the detour tunnel is typically sealed or abandoned after construction. The structure requires water pressure-resistant lining to address water pressure issues or additional drainage tunnels for separate drainage and pressure relief. Therefore, this method involves a large workload, complex handling, and poor economic efficiency. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a circuitous tunnel structure that combines permanent and temporary methods for tunneling through complex karst caves; and also to propose a construction method for this circuitous tunnel structure.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The tunnel is a combination of permanent and temporary passageways through a karst cave. The tunnel includes a starting section, a passage section through the karst cave, and an ending section connected in sequence. The passageway structure includes a passageway connected to the starting section at one end, and the other end of the passageway extends to the ending section after passing through the upstream of the karst cave. The ending section has a tunnel bottom culvert connected to the passageway, and the other end of the tunnel bottom culvert is connected to the downstream of the karst cave. The passageway inside the karst cave has a water passage hole on the upstream side of the karst cave. The portion of the passageway between the upstream of the karst cave and the starting section is sealed.

[0007] During tunnel construction, the water flow inside the tunnel is intercepted by a meandering tunnel located within a karst cave. The water flows through water holes into the meandering tunnel, then passes through the meandering tunnel and the tunnel bottom culvert before flowing downstream of the karst cave, reducing safety hazards. The sidewalls of the meandering tunnel are sidewalls, and a top support is installed on its top.

[0008] In the aforementioned tunnel structure that combines permanent and temporary passage through a karst cave, the meandering tunnel includes an exit tunnel connected to the starting section, a parallel tunnel connected to the exit tunnel and parallel to the tunnel, and an access tunnel connected to the parallel tunnel. The tunnel bottom culvert is connected to the access tunnel. The sealing is located in the exit tunnel. The parallel tunnel passes through the upstream of the karst cave, and a water collection hole is provided at the parallel tunnel.

[0009] Water collection holes are distributed on the sidewalls and topwalls of the parallel section of the tunnel.

[0010] In the aforementioned winding tunnel structure that combines permanent and temporary tunneling through karst caves, a maintenance door is installed above the sealing section. Once the maintenance door is closed, water flow will not enter the lead-out section tunnel.

[0011] In the aforementioned winding tunnel structure that combines permanent and temporary tunnels through karst caves, the sealing area is provided with steps on both sides of the inspection door.

[0012] The construction method for a combined permanent and temporary tunnel structure that traverses a karst cave includes the following steps:

[0013] Step 1: Tunnel construction reveals complex karst caves;

[0014] Step 2: Excavate a meandering tunnel on the sidewall of the initial section; the sidewall of the meandering tunnel should be located near the upstream of the karst cave.

[0015] Step 3: Construct the lead-out section tunnel to the upstream of the karst cave, and then construct the parallel section tunnel so that the parallel section tunnel passes directly through the karst cave. Set water passage holes on the sidewall of the parallel section tunnel near the upstream side of the karst cave, and construct top support and water collection holes. The water passage holes connect the upstream of the karst cave and the parallel section tunnel, and the water in the karst cave enters the parallel section tunnel through the water passage holes.

[0016] Step 4: Construct the access tunnel until reaching the sidewall of the end section, and install top support and water collection holes;

[0017] Step 5: The meandering tunnel enters the final section. Construction ramps are set up on both sides of the meandering tunnel at the final section. The end of the meandering tunnel is connected to the downstream of the karst cave.

[0018] Step Six: Continue tunnel construction in the forward direction using the detour tunnel;

[0019] Step 7: During the construction of steps 2 to 6, the surveying and exploration of the karst caves shall be carried out simultaneously, and the sections of the tunnel that pass through the karst caves shall be treated.

[0020] Step 8: After the karst cave treatment is completed, construct the tunnel bottom box culvert and box culvert end in the end section. One end of the tunnel bottom box culvert is connected to the downstream of the karst cave, and the other end is connected to the meandering tunnel.

[0021] Step 9: Construct a sealing structure within the lead-out section tunnel, and install an inspection door on top of the sealing structure.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] Setting up a detour tunnel outside the karst cave as a temporary construction passage opens up a working face for tunnel construction ahead, reducing interference between tunnel construction and karst cave exploration and treatment, ensuring uninterrupted and safe tunnel construction, and ensuring the construction period; later, the detour tunnel can be used as a permanent drainage channel to ensure the effective use of the project, reduce investment, and ensure the safe operation of the tunnel, which has great practical significance and economic value. Attached Figure Description

[0024] Figure 1 This is a planar schematic diagram of the present invention.

[0025] Figure 2 For temporary works Figure 1 Cross-sectional view at point AA.

[0026] Figure 3 For temporary works Figure 1 Cross-sectional view at CC.

[0027] Figure 4 For permanent works Figure 1 Cross-sectional view at point AA.

[0028] Figure 5 For permanent works Figure 1 Cross-sectional view at CC.

[0029] Figure 6 for Figure 1 Cross-sectional view at point BB.

[0030] Figure 7 for Figure 4 Cross-sectional view at point DD.

[0031] In the diagram, 11 is the starting section; 12 is the crossing section; 13 is the ending section; 21 is the upstream section; 22 is the downstream section; 3 is the box culvert at the bottom of the tunnel; 4 is the water passage hole; 5 is the sealing section; 51 is the step; 61 is the lead-out tunnel; 62 is the parallel tunnel; 63 is the connection tunnel; 7 is the water collection hole; 8 is the inspection door; and 10 is the end of the box culvert. Detailed Implementation

[0032] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0033] like Figure 1 As shown, the tunnel includes a starting section 11, a crossing section 12 that passes through a complex karst cave, and an ending section 13 that are connected in sequence. The height of the bottom surface of the tunnel gradually decreases from the starting section 11 to the ending section 13.

[0034] like Figure 1 The tunnel shown is a combined permanent and temporary passageway structure traversing a karst cave. It includes a passageway connected at one end to the initial section 11, and the other end of the passageway extends from the upstream section 21 of the karst cave to the final section 13. Figure 5 As shown, the final section 13 is equipped with a tunnel bottom box culvert 3 that connects to the meandering tunnel, as... Figure 4 As shown, the other end of the box culvert 3 at the bottom of the tunnel is connected to the downstream end 22 of the karst cave, as... Figure 2 and Figure 4 As shown, a water passage 4 is provided on the side of the winding tunnel located inside the cave facing the upstream side 21 of the cave, such as... Figure 4 and Figure 5 As shown, the section of the meandering tunnel located between the upstream section 21 of the karst cave and the initial section 11 is equipped with a sealing block 5, and an inspection door 8 is located above the sealing block 5. Figure 4 As shown, the blockage 5 is provided with steps 51 on both sides of the inspection door 8.

[0035] During tunnel construction, the water flow inside the tunnel is intercepted by a meandering tunnel located within the karst cave. The water flows through water hole 4 into the meandering tunnel, and then flows through the meandering tunnel and the box culvert 3 at the bottom of the tunnel before flowing downstream 22 of the karst cave, reducing safety hazards.

[0036] like Figure 1 As shown, the detour tunnel includes an exit tunnel 61 connected to the starting section 11, a parallel tunnel 62 connected to the exit tunnel 61 and parallel to the tunnel, and an access tunnel 63 connected to the parallel tunnel 62. The tunnel bottom culvert 3 connects to the access tunnel 63. A sealing 5 is located within the exit tunnel 61. The parallel tunnel 62 passes upstream of the karst cave 21, and a water collection hole 7 is located at the parallel tunnel 62. Figure 6As shown, water collection holes 7 are distributed on the side walls and top walls of the parallel section tunnel 62. The bottom height of the meandering tunnel gradually decreases from the leading section tunnel 61 to the connecting section tunnel 63.

[0037] The clear dimensions of the bypass tunnel are 5m × 6m (width × height). The inspection door 8 measures 1m × 1.5m. The box culvert 3 at the tunnel bottom measures 3m × 2.5m. The water collection holes 7 are 76mm diameter boreholes, 4–5m deep, with a spacing of 1.5m between adjacent holes, arranged in a quincunx pattern. The water passage holes 4 measures 1–2m × 1–2m, with a horizontal and vertical spacing of 0.5m–2m.

[0038] The construction method for the aforementioned tunnel crossing a karst cave using a combination of permanent and temporary tunnel structures includes the following steps:

[0039] Step 1: Tunnel construction reveals complex karst caves;

[0040] Step 2: Excavate a meandering tunnel on the side wall of the initial section 11; the side wall of the meandering tunnel is located near the upstream 21 of the karst cave.

[0041] Step 3: Construct the lead-out section tunnel 61 to the upstream of the karst cave 21, and then construct the parallel section tunnel 62 so that the parallel section tunnel 62 passes through the karst cave. Water passage hole 4 is set on the side wall of the parallel section tunnel 62 near the upstream of the karst cave 21, and top support and water collection hole 7 are constructed.

[0042] Step 4: Construct the access tunnel 63 until reaching the side wall of the end section 13, and construct the top support and water collection hole 7;

[0043] Step 5: Enter the final section 13 via the detour tunnel, as follows... Figure 3 As shown, construction ramps are set on both sides of the meandering tunnel at the end section 13, and the end of the meandering tunnel is connected to the downstream of the karst cave 22.

[0044] Step Six: Continue tunnel construction in the forward direction using the detour tunnel;

[0045] Step 7: During the construction of steps 2 to 6, the surveying and exploration of the karst caves shall be carried out simultaneously, and the sections of the tunnel that pass through the karst caves shall be treated.

[0046] Step 8: After the cave treatment is completed, as follows Figure 4 and 5 As shown, a box culvert 3 and a box culvert end 10 are constructed in the end section 13. One end of the box culvert 3 is connected to the downstream of the karst cave 22, and the other end is connected to the meandering tunnel.

[0047] Step 9: Construct sealing 5 within the lead-out tunnel 61, such as... Figure 4 and 7 As shown, an inspection door 8 is installed on top of the seal 5.

[0048] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A detour tunnel structure for changing the flow direction of water in a karst cave, comprising a starting section (11), a tunneling section (12) for tunneling through the karst cave, and an ending section (13) connected in sequence, characterized in that, The detour tunnel structure comprises a detour tunnel which is communicated with a starting section (11) at one end and extends to an ending section (13) after passing through an upstream (21) of a karst cave, wherein a tunnel bottom box culvert (3) is arranged in the ending section (13) and communicated with the detour tunnel, the other end of the tunnel bottom box culvert (3) is communicated with a downstream (22) of the karst cave, a water passing hole (4) is arranged on the side of the detour tunnel which faces the upstream (21) of the karst cave, and a blocking (5) is arranged in the part of the detour tunnel between the upstream (21) of the karst cave and the starting section (11); the detour tunnel comprises an outgoing section tunnel (61) communicated with the starting section (11), a parallel section tunnel (62) communicated with the outgoing section tunnel (61) and parallel to the tunnel, and an access section tunnel (63) communicated with the parallel section tunnel (62), the tunnel bottom box culvert (3) is communicated with the access section tunnel (63), the blocking (5) is arranged in the outgoing section tunnel (61), the parallel section tunnel (62) passes through the upstream (21) of the karst cave, and a water collecting hole (7) is arranged at the parallel section tunnel (62); a maintenance door (8) is arranged above the blocking (5).

2. The tunneling through the cave permanent temporary combined detour gallery structure according to claim 1, characterized in that, The blocking (5) is arranged on both sides of the maintenance door (8) and is provided with steps (51).

3. The construction method of the tunneling through the cave combined with the detour gallery structure according to claim 1, characterized in that, The method comprises the following steps: Step one, tunnel construction reveals a complex karst cave; Step two, a detour tunnel is excavated on the side wall of the starting section (11); Step three, the outgoing section tunnel (61) is constructed to the upstream (21) of the karst cave, then the parallel section tunnel (62) is constructed, the parallel section tunnel (62) passes through the karst cave, the water passing hole (4) is arranged on the side wall of the parallel section tunnel (62) which is close to the upstream (21) of the karst cave, and the top support and the water collecting hole (7) are constructed; Step four, the access section tunnel (63) is constructed until the side wall of the ending section (13) is reached, and the top support and the water collecting hole (7) are constructed; Step five, the detour tunnel enters the ending section (13), the construction slope is arranged on both sides of the detour tunnel in the ending section (13), and the end of the detour tunnel is connected with the downstream (22) of the karst cave; Step six, the tunnel construction in the forward direction is continued by using the detour tunnel; Step seven, the surveying and mapping of the karst cave is carried out synchronously during the construction of steps two to six, and the treatment of the tunnel passing through the karst cave section is carried out; Step eight, after the treatment of the karst cave is completed, the tunnel bottom box culvert and the box culvert end head (10) are constructed in the ending section (13), one end of the tunnel bottom box culvert (3) is connected with the downstream (22) of the karst cave, and the other end is connected with the detour tunnel; Step nine, the blocking (5) is constructed in the outgoing section tunnel (61), and the maintenance door (8) is constructed on the top of the blocking (5).

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