Tunnel structure for underneath passing large underground river section in water-rich karst area and construction method

Abstract

The invention discloses a tunnel structure for underneath passing a large underground river section in a water-rich karst area and a construction method, and relates to the technical field of tunnel engineering. The tunnel structure comprises a tunnel body, a tunnel structure reinforcing layer is arranged in a tunnel underneath passing large underground river section, a drainage pipeline is reserved in the tunnel structure reinforcing layer, and multi-stage drainage holes are formed in the water diversion face side of the tunnel structure reinforcing layer. The multi-stage drainage holes comprise the daily drainage hole, the alarm drainage hole and the shutdown drainage hole which are connected with the filter screens of different stages respectively, underground water of underground rivers can be effectively guided and drained, and long-term retention of accumulated water is avoided. The system further comprises a maintenance ladder and a health monitoring device, and reliable operation of the drainage system is ensured. According to the structure, the underground river runoff path is maintained, meanwhile, the safety and durability of the tunnel structure are improved, and the construction cost and the ecological influence are reduced.

Description

Technical Field

[0001] This invention relates to the field of tunnel engineering technology, and in particular to a tunnel structure and construction method for tunneling under a large underground river in a water-rich karst area. Background Technology

[0002] As transportation infrastructure expands westward and southwestward, tunnel projects often traverse water-rich karst landforms and encounter large underground rivers. Current technologies for tunnels passing under underground rivers primarily employ methods such as grouting to block water, drainage tunnels for diversion, or structural reinforcement. However, these solutions have the following drawbacks: firstly, blocking or diverting the river disrupts its flow path, affecting the groundwater ecological balance; secondly, the construction costs are high, and long-term water accumulation may lead to structural leakage and safety risks. For example, while the diversion methods disclosed in Chinese patents CN114991811A and CN114017040A maintain the flow path, they cannot effectively drain surface water from the tunnel's upstream side; the sealing method in CN116971334A involves a large engineering workload and significant ecological impact.

[0003] Therefore, there is an urgent need for a tunnel solution that can maintain the flow path of underground rivers, effectively drain water, and ensure structural safety. Summary of the Invention

[0004] The purpose of this invention is to provide a tunnel structure and construction method for passing under a large underground river in a water-rich karst area, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides a tunnel structure for passing under a large underground river section in a water-rich karst area, comprising a tunnel body, a tunnel structure reinforcement layer provided under the tunnel body passing under the large underground river section, and a drainage pipe reserved inside the tunnel structure reinforcement layer; the water intake side of the tunnel structure reinforcement layer is provided with multiple drainage holes for draining water accumulated on the water intake side; the back water side of the tunnel structure reinforcement layer is provided with back water drainage holes for draining water accumulated on the back water side.

[0006] Preferably, the multi-stage drainage holes include daily drainage holes, alarm drainage holes, and shutdown drainage holes; the daily drainage holes are located at the bottom of the tunnel structure reinforcement layer and are connected to a drainage blind pipe, and are used to drain accumulated water on the water-facing side of the tunnel structure reinforcement layer; the alarm drainage holes are located in the middle of the tunnel structure reinforcement layer, and are used to drain underground river water in the early rainy season; the shutdown drainage holes are located at the top of the tunnel structure reinforcement layer.

[0007] Preferably, the daily drainage hole is connected to a three-stage filter screen, which includes a first filter screen for filtering gravel, a second filter screen for filtering sand and fine gravel, and a third filter screen for filtering mud and fine sand. The mesh size of the first filter screen, the second filter screen, and the third filter screen decreases sequentially.

[0008] Preferably, the mesh size of the first filter screen is 10.0mm × 10.0mm, the mesh size of the second filter screen is 5.0mm × 5.0mm, and the mesh size of the third filter screen is 1.0mm × 1.0mm.

[0009] Preferably, the alarm drain hole is connected to a secondary filter screen, which includes a fourth filter screen and a fifth filter screen; the fourth filter screen is used to filter sand and fine gravel, and the mesh size of the fourth filter screen is 5.0mm×5.0mm; the fifth filter screen is used to filter mud and fine sand, and the mesh size of the fifth filter screen is 1.0mm×1.0mm.

[0010] Preferably, it also includes a maintenance ladder that extends from the interior of the tunnel body to the bottom of the underground river for the maintenance of drainage holes and filters.

[0011] Preferably, it also includes a health monitoring device, which includes a water pressure monitoring sensor. The water pressure monitoring sensor is disposed on the outside of the tunnel structure reinforcement layer and is used to monitor water pressure changes in real time.

[0012] Preferably, the tunnel body is divided longitudinally into a section with an underground river intersection, a structurally reinforced section, and a structurally normal section, and the tunnel structural reinforcement layer is located in the section with the underground river intersection.

[0013] Preferably, the concrete used in the reinforced section of the structure is at least one grade higher than the concrete used in the normal section of the structure, and a base is provided at the bottom of the underground river crossing section, the base resting on stable bedrock.

[0014] This invention provides a tunnel construction method for tunneling under a large underground river in a water-rich karst area, comprising the following steps: Step 1: Preliminary drawing of a typical cross-sectional diagram of the tunnel and the underground river using geological survey methods; Step 2: After the underground river is exposed during tunnel construction, a detailed typical cross-sectional diagram is drawn through on-site reconnaissance; Step 3: Based on the spatial relationship between the tunnel and the underground river, the tunnel is longitudinally divided into an underground river intersection section, a structurally reinforced section, and a structurally normal section; Step 4: Pre-treatment of the underground river intersection section, including surrounding rock reinforcement and tunnel bottom base construction, wherein the surrounding rock reinforcement adopts anchor spraying support; Step 5: Implementation of the above-mentioned tunnel structure in the underground river intersection section, including construction of a tunnel structural reinforcement layer, pre-reservation of drainage pipes inside the tunnel structural reinforcement layer, setting of multi-stage drainage holes on the water intake side of the tunnel structural reinforcement layer, and installation of filter screens and drainage blind pipes; Step 6: Installation of health monitoring devices in the underground river intersection section and the structurally reinforced section to monitor water pressure changes in real time.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects.

[0016] 1. This invention uses a tunnel structure reinforcement layer and a graded drainage system to promptly drain groundwater, preventing structural damage caused by long-term water immersion.

[0017] 2. This invention can maintain the flow path of underground river water, and protect the groundwater balance and ecological environment.

[0018] 3. The present invention has a reasonable structural design, which reduces the amount of additional engineering work and has low construction costs.

[0019] 4. This invention improves operational safety and ensures reliable operation and maintenance by providing real-time early warnings through a health monitoring system. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the tunnel construction method of the present invention.

[0022] Figure 2 This is a preliminary cross-sectional drawing of a typical section between the tunnel and the underground river of the present invention.

[0023] Figure 3 This is a detailed cross-sectional drawing of a typical section between the tunnel and the underground river of this invention.

[0024] Figure 4 This is a schematic diagram of the longitudinal section division of the tunnel according to the present invention.

[0025] Figure 5 This is a schematic diagram of the construction of the tunnel bottom base of the present invention.

[0026] Figure 6 This is a schematic diagram of the tunnel structure of the present invention.

[0027] Figure 7 This is a schematic diagram of the health monitoring points for this invention.

[0028] In the diagram: 1. Tunnel structure reinforcement layer; 2. Drainage pipe; 3. Daily drainage hole; 4. Alarm drainage hole; 5. Shutdown drainage hole; 6. Three-stage filter screen; 7. Two-stage filter screen; 8. Backwater drainage hole; 9. Maintenance ladder; 10. Health monitoring device; 11. Base; 12. Drainage blind pipe. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figure 6 As shown, the present invention provides a tunnel structure for passing under a large underground river section in a water-rich karst area, including a tunnel body, a tunnel structure reinforcement layer 1 provided under the tunnel body passing under the large underground river section, and a drainage pipe 2 reserved inside the tunnel structure reinforcement layer 1; the water intake side of the tunnel structure reinforcement layer 1 is provided with multiple drainage holes for draining water accumulated on the water intake side; the back water side of the tunnel structure reinforcement layer 1 is provided with back water drainage holes 8 for draining water accumulated on the back water side.

[0031] Further optimization of the scheme: the multi-stage drainage holes include daily drainage hole 3, alarm drainage hole 4, and shutdown drainage hole 5; daily drainage hole 3 is located at the bottom of the tunnel structure reinforcement layer 1 and is connected to a drainage blind pipe 12, and is used to drain the water accumulated on the water-facing side of the tunnel structure reinforcement layer 1; alarm drainage hole 4 is located in the middle of the tunnel structure reinforcement layer 1, and is used to drain the underground river groundwater in the early rainy season; shutdown drainage hole 5 is located at the top of the tunnel structure reinforcement layer 1.

[0032] The scheme is further optimized so that the daily drainage hole 3 is connected to a three-stage filter screen 6. The three-stage filter screen 6 includes a first filter screen for filtering gravel, a second filter screen for filtering sand and fine gravel, and a third filter screen for filtering mud and fine sand. The mesh size of the first filter screen, the second filter screen and the third filter screen decreases in sequence.

[0033] Further optimization of the design: the mesh size of the first filter is 10.0mm×10.0mm, the mesh size of the second filter is 5.0mm×5.0mm, and the mesh size of the third filter is 1.0mm×1.0mm.

[0034] The scheme is further optimized so that the alarm drainage hole 4 is connected to a secondary filter screen 7, which includes a fourth filter screen and a fifth filter screen. The fourth filter screen is used to filter sand and fine gravel, and the mesh size of the fourth filter screen is 5.0mm×5.0mm. The fifth filter screen is used to filter mud and fine sand, and the mesh size of the fifth filter screen is 1.0mm×1.0mm.

[0035] Further optimization of the plan also includes maintenance ladder 9, which extends from the interior of the tunnel body to the bottom of the underground river and is used for maintenance of drainage holes and filters.

[0036] Further optimization of the scheme also includes a health monitoring device 10, which includes a water pressure monitoring sensor. The water pressure monitoring sensor is installed on the outside of the tunnel structure reinforcement layer 1 and is used to monitor water pressure changes in real time.

[0037] The scheme was further optimized, and the main body of the tunnel was divided longitudinally into a section with an underground river intersection, a structurally reinforced section, and a structurally normal section. The tunnel structural reinforcement layer 1 was set in the section with the underground river intersection.

[0038] The scheme was further optimized so that the concrete used in the reinforced section was at least one grade higher than that used in the normal section. A base 11 was installed at the bottom of the underground river crossing section, and the base 11 rested on the stable bedrock.

[0039] like Figure 1 As shown, the present invention provides a tunnel construction method for passing under a large underground river section in a water-rich karst area, including the following steps.

[0040] Step 1: Using underground river information obtained through geological survey reports, advanced geological boreholes, ground-penetrating radar, borehole photography, and microseismic detection, a preliminary cross-sectional diagram of the tunnel and the underground river is drawn, such as... Figure 2 As shown.

[0041] Step Two: After the underground river is exposed during tunnel construction, a site survey and detailed profile drawing are conducted to understand the river's direction, scale, spatial relationship between the river and the tunnel, groundwater flow status, groundwater source, relationship between groundwater and surface water, and stability of the surrounding rock in the river section, etc. Figure 3 As shown.

[0042] Step 3: Based on the spatial relationship between the tunnel and the underground river, longitudinal zoning and fortification are implemented, dividing the tunnel longitudinally into sections where the underground river intersects, structurally reinforced sections, and structurally normal sections, such as... Figure 4As shown. Among them, the normal structural section adopts conventional design methods, such as using C30 grade concrete; the reinforced structural section adopts reinforced concrete grade, such as one grade higher than that of the normal structural section, such as using C35 grade; the underground river crossing section adopts the tunnel structure reinforcement layer 1 proposed in this invention.

[0043] Step 4: Pre-treatment of the underground river intersection section, including surrounding rock reinforcement and construction of the tunnel base 11. Surrounding rock reinforcement can be achieved using shotcrete anchoring. If the surrounding rock at the top of the underground river has poor stability or has been submerged in water for a long time, shotcrete anchoring combined with anchor bolts is required to reinforce the surrounding rock within the tunnel structure's influence range. Construction of the tunnel base 11 at the bottom ensures it sits on stable bedrock, maintaining the stability of the tunnel structure. Figure 5 As shown.

[0044] Step 5: Implement the aforementioned tunnel structure at the crossroads of the underground river, including constructing the tunnel structure reinforcement layer 1, reserving drainage pipes 2 inside the tunnel structure reinforcement layer 1, setting up multi-stage drainage holes on the water intake side of the tunnel structure reinforcement layer 1, and installing filter screens and blind drainage pipes 12, such as... Figure 6 As shown.

[0045] Step Six: Install health monitoring devices at the intersection of the underground river and the structural reinforcement section to obtain real-time water pressure on the outside of the tunnel structure. When the water pressure monitoring value changes abruptly, first check the underground river for water accumulation and whether there is a necessary connection between the sudden change in the water pressure monitoring value on the structure and the underground river. If there is water accumulation in the underground river, check whether the drainage holes are blocked. If blocked, repair them promptly. After repair, observe whether the water pressure monitoring value returns to normal. If there is no water accumulation at the underground river and the drainage holes are not blocked, but the structural water pressure monitoring value still changes abruptly, the influence of the underground river can be ruled out, and a professional unit should be consulted to investigate the cause. The health check points are as follows: Figure 7 As shown.

[0046] The present invention provides a tunnel structure and construction method for passing under a large underground river in a water-rich karst area. By constructing a tunnel structure reinforcement layer 1 around the tunnel structure and reserving a drainage pipe 2 inside the tunnel structure reinforcement layer 1, the water accumulated on the water intake side can be drained away in a timely manner, avoiding the long-term retention of water on the water intake side, which would pose a safety hazard to the tunnel structure.

[0047] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A tunnel structure for tunneling under a large underground river section in a water-rich karst area, characterized in that, The tunnel includes a main body, and a tunnel structure reinforcement layer (1) is provided under the section of a large underground river. A drainage pipe (2) is reserved inside the tunnel structure reinforcement layer (1). The water intake side of the tunnel structure reinforcement layer (1) is provided with multiple drainage holes for draining water from the water intake side. The back water side of the tunnel structure reinforcement layer (1) is provided with back water drainage holes (8) for draining water from the back water side.

2. The tunnel structure for tunneling under a large underground river in a water-rich karst area according to claim 1, characterized in that, The multi-stage drainage holes include daily drainage holes (3), alarm drainage holes (4), and shutdown drainage holes (5); the daily drainage holes (3) are located at the bottom of the tunnel structure reinforcement layer (1) and are connected to a drainage blind pipe (12). The daily drainage holes (3) are used to drain the water accumulated on the water-facing side of the tunnel structure reinforcement layer (1); the alarm drainage holes (4) are located in the middle of the tunnel structure reinforcement layer (1). The alarm drainage holes (4) are used to drain the underground river groundwater in the early rainy season; the shutdown drainage holes (5) are located at the top of the tunnel structure reinforcement layer (1).

3. The tunnel structure for tunneling under a large underground river section in a water-rich karst area according to claim 2, characterized in that, The daily drainage hole (3) is connected to a three-stage filter screen (6), which includes a first filter screen for filtering gravel, a second filter screen for filtering sand and fine gravel, and a third filter screen for filtering mud and fine sand. The mesh size of the first filter screen, the second filter screen and the third filter screen decreases sequentially.

4. The tunnel structure for tunneling under a large underground river section in a water-rich karst area according to claim 3, characterized in that, The first filter screen has a mesh size of 10.0mm × 10.0mm, the second filter screen has a mesh size of 5.0mm × 5.0mm, and the third filter screen has a mesh size of 1.0mm × 1.0mm.

5. The tunnel structure for passing under a large underground river section in a water-rich karst area according to claim 2, characterized in that, The alarm drain hole (4) is connected to a secondary filter screen (7), which includes a fourth filter screen and a fifth filter screen. The fourth filter screen is used to filter sand and fine gravel, and the mesh size of the fourth filter screen is 5.0mm×5.0mm. The fifth filter screen is used to filter mud and fine sand, and the mesh size of the fifth filter screen is 1.0mm×1.0mm.

6. The tunnel structure for passing under a large underground river section in a water-rich karst area according to claim 1, characterized in that, It also includes a maintenance ladder (9) that extends from the interior of the tunnel body to the bottom of the underground river for the maintenance of drainage holes and filters.

7. The tunnel structure for passing under a large underground river section in a water-rich karst area according to claim 1, characterized in that, It also includes a health monitoring device (10), which includes a water pressure monitoring sensor. The water pressure monitoring sensor is located on the outside of the tunnel structure reinforcement layer (1) and is used to monitor water pressure changes in real time.

8. The tunnel structure for passing under a large underground river section in a water-rich karst area according to claim 1, characterized in that, The tunnel body is divided longitudinally into a cross section of underground rivers, a structurally reinforced section and a structurally normal section, and the tunnel structural reinforcement layer (1) is set in the cross section of underground rivers.

9. The tunnel structure for tunneling under a large underground river section in a water-rich karst area according to claim 8, characterized in that, The concrete used in the reinforced section of the structure is at least one grade higher than that used in the normal section of the structure. A base (11) is provided at the bottom of the underground river crossing section, and the base (11) sits on stable bedrock.

10. A method for constructing a tunnel under a large underground river in a water-rich karst area, characterized in that, Includes the following steps: Step 1: Using geological survey methods, preliminary cross-sectional diagrams of the tunnel and underground river are drawn; Step Two: After the underground river is exposed during tunnel construction, a typical cross-sectional drawing is prepared through on-site survey; Step 3: Based on the spatial relationship between the tunnel and the underground river, the tunnel is longitudinally divided into the underground river intersection section, the structurally reinforced section, and the structurally normal section; Step 4: Pre-treatment of the underground river intersection section, including the reinforcement of the surrounding rock and the construction of the tunnel bottom base (11), wherein the surrounding rock reinforcement adopts anchor spraying support; Step 5: Implement the tunnel structure according to any one of claims 1-9 at the cross section of the underground river, including constructing a tunnel structure reinforcement layer (1), reserving a drainage pipe (2) inside the tunnel structure reinforcement layer (1), setting up multi-stage drainage holes on the water intake side of the tunnel structure reinforcement layer (1), and installing a filter screen and a drainage blind pipe (12). Step Six: Install health monitoring devices at the crossroads of the underground river and the structurally reinforced sections to monitor water pressure changes in real time.

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