Integrated drainage supporting structure suitable for water-rich fracture zone tunnel

Abstract

The utility model discloses an integrated drainage supporting structure suitable for a tunnel in a water-rich fracture zone, which comprises a primary sprayed concrete layer, a re-sprayed concrete layer, a waterproof layer and a secondary lining layer which are arranged on the wall surface of the tunnel, and is characterized by further comprising a plurality of I-shaped steel pairs which are uniformly arranged along the direction of the tunnel at certain intervals, the transverse connection steel pipes are horizontally connected between the I-shaped steel pairs in a penetrating mode, and the reinforcing ribs, the filtering layers, the vertical drainage water diversion pipes and the transverse drainage water diversion pipes are welded between the surfaces of flange plates on the inner sides of the I-shaped steel pairs. On the basis of the structural design of the original steel arch, the joist steel does not need to be additionally cut or deformed, and only the splicing mode of the original steel arch needs to be ingeniously changed, so that the joist steel pairs and the transverse connecting steel pipes can be connected into an integral structure to play a supporting role of the traditional steel arch; and meanwhile, vertical and transverse water guiding and draining effects are achieved, so that construction of a vertical drainage blind pipe and a transverse drainage blind pipe can be omitted, procedures are saved, and the construction time is shortened.

Description

Technical Field

[0001] This utility model belongs to the field of tunnel construction technology, specifically relating to an integrated drainage support structure suitable for tunnels in water-rich fractured zones. Background Technology

[0002] Tunnels, as an important form of infrastructure construction, are increasingly widely used in highways, railways, and underground transportation. With increasing construction demands, the geological environment faced by tunnel construction is becoming increasingly complex, especially in tunnel construction in water-rich fractured zones. Due to abundant groundwater, often accompanied by large-scale rock fracturing and loose rock mass structures, hydrological conditions change extremely complexly during construction, and groundwater distribution and pressure variations are difficult to predict, easily leading to water inrush and gushing phenomena. In water-rich fractured zones, existing tunnel support systems generally adopt the following construction steps: first, advance water exploration; second, advance support construction based on the exploration results; third, initial support and secondary lining construction; and fourth, simultaneous construction of the drainage system. However, the above method has the following drawbacks:

[0003] (1) During the construction of the drainage system, vertical and horizontal drainage blind pipes are usually pre-embedded before the secondary lining grouting construction of the tunnel, so as to drain the water behind the tunnel lining into the central water ditch of the tunnel, reduce the water pressure behind the lining structure, and prevent water leakage from the tunnel wall during later use. However, during the secondary lining grouting construction of the tunnel, the pumped concrete has a certain pressure. Under greater pressure, the concrete will squeeze the drainage blind pipes, thereby causing damage to the drainage blind pipes. At the same time, the concrete may also seep into the drainage blind pipes and block the drainage channel. Therefore, if the construction quality control is not good, the existing drainage system with drainage blind pipes is prone to failure, which will cause water dripping and seepage on the tunnel wall after the tunnel support system is completed.

[0004] (2) The drainage system itself does not have load-bearing capacity. The drainage system can only perform drainage function after the concrete strength reaches the required level after the secondary lining construction is completed. Therefore, before this process, the drainage system cannot meet and cope with sudden drainage needs.

[0005] (3) The construction process involves many steps and is complex, which delays the construction progress and further increases the risk of water inrush and gushing during construction. Utility Model Content

[0006] To address the aforementioned problems, the purpose of this utility model is to provide an integrated drainage support structure suitable for tunnels in water-rich fractured zones.

[0007] This utility model is achieved through the following technical solution.

[0008] An integrated drainage support structure suitable for tunnels in water-rich fractured zones includes a primary shotcrete layer, a secondary shotcrete layer, a waterproof layer, and a secondary lining layer set on the tunnel wall. The structure is characterized by further comprising: several pairs of I-beams evenly spaced along the tunnel direction; horizontally penetrating and connecting transverse steel pipes between the pairs of I-beams; reinforcing ribs welded between the inner flanges of the I-beams; a filter layer; vertical water pipes; and horizontal water pipes.

[0009] Several H-beams are cast into a secondary shotcrete layer, with their outer surfaces abutting against the primary shotcrete layer, to directly bear the surrounding rock pressure. Each H-beam pair is formed by two identical H-beams with a permeable gap between their flanges and joined closely together at their webs, thus creating a vertical drainage channel within the H-beam pair. A filter layer is placed between the outer flange of the H-beam pair and the primary shotcrete layer. A sealing layer fills the permeable gap between the inner flanges of the H-beam pair. Vertical water pipes are arranged along the cross-section of the tunnel where the H-beam pair is located. Furthermore, one end of the vertical water inlet pipe extends obliquely upward through the initial shotcrete layer into the tunnel soil, and the other end passes through the permeable gap between the filter layer and the outer flange plate to be inserted into the interior of the I-beam pair; the horizontal connecting steel pipe has a drain outlet at the position where it penetrates into the interior of the I-beam pair; the horizontal water inlet pipe is correspondingly set on the tunnel wall outside the horizontal connecting steel pipe, and one end of the horizontal water inlet pipe extends obliquely upward through the initial shotcrete layer into the tunnel soil, while the other end protrudes outside the initial shotcrete layer and is connected to the horizontal connecting steel pipe outside the I-beam pair through a plastic hose.

[0010] Preferably, the inner surface of the I-beam, i.e., the web surface at the joint between the I-beams, is coated with an isolation protective layer.

[0011] Preferably, the vertical and horizontal water pipes located in the tunnel soil are provided with several water inlets and are wrapped with geotextile.

[0012] Preferably, the permeation pipe has a plurality of permeation holes evenly distributed on its wall, and the permeation pipe is wrapped with geotextile.

[0013] Preferably, the filter layer comprises a wire mesh layer and a geotextile layer laid sequentially from the outside to the inside on the wall of the initial shotcrete layer.

[0014] Preferably, the width of the filter layer is 1.2-1.5 times the width of the I-beam pair, and the water-permeable gap of the I-beam pair is located on the circumferential centerline of the filter layer.

[0015] Preferably, the width of the permeable gap is 3-4 cm, and the outer diameter of the vertical water inlet pipe is slightly smaller than the width of the permeable gap.

[0016] Preferably, the spacing between adjacent pairs of I-beams is controlled to be 0.5-0.8m.

[0017] Preferably, a steel mesh is provided in the sprayed concrete layer, and the steel mesh is welded to the I-beams and cross steel pipes.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] (1) Based on the original steel arch frame structure design, this utility model does not require additional cutting or deformation of the I-beams. By cleverly changing the splicing method of the original steel arch frame, the I-beams and horizontal connecting steel pipes can be connected into an integral structure to play the supporting role of the traditional steel arch frame. At the same time, it also has vertical and horizontal drainage functions, thus eliminating the need for construction of vertical and horizontal drainage blind pipes, saving procedures and shortening construction time.

[0020] (2) After the installation of the I-beams, horizontal connecting steel pipes, horizontal water diversion pipes and vertical water diversion pipes is completed, the present invention can realize the functions of support and drainage without waiting for the secondary lining layer to be completed. Therefore, the integrated drainage support structure of the present invention has better timeliness and can more flexibly meet the drainage needs in the construction of water-rich fractured tunnels.

[0021] (3) The drainage channel of this utility model is formed by connecting and assembling I-beams and cross steel pipes. It can withstand greater external pressure and mechanical collisions, and is not easily damaged or failed during subsequent secondary lining construction, thus effectively ensuring the drainage of tunnel seepage.

[0022] (4) Typically, water-rich fractured zones are formed by tectonic movements. Within the fault zone, rocks are fractured and fissures are developed. Groundwater accumulates in a closed geological environment, easily forming a high pressure head. The vertical drainage channel of this utility model is formed by I-beams, and the horizontal drainage channel is formed by horizontal connecting steel pipes. It can resist large internal water pressure. The drainage channel will not be damaged due to excessive water pressure during use, thus effectively ensuring and maintaining the normal drainage of the tunnel. It can better prevent sudden water inrush during tunnel construction and maintain a dry environment inside the tunnel after completion, avoiding the occurrence of dripping and seepage on the tunnel wall. Attached Figure Description

[0023] Figure 1 This is the main view of the present invention.

[0024] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0025] Figure 3 for Figure 1 Sectional view at point AA;

[0026] Figure 4 for Figure 3 Enlarged view of section BB;

[0027] Figure 5 for Figure 4 Enlarged view of point D in the middle;

[0028] Figure 6 A three-dimensional structural diagram showing the connection between the I-beams, vertical water pipes, and horizontal connecting steel pipes;

[0029] Figure 7 for Figure 6 Enlarged view of point C in the middle;

[0030] The meanings of the labels in the above diagrams are as follows: Tunnel 1, initial shotcrete layer 2, I-beam pair 3, permeable gap 301, isolation and protective layer 302, vertical water intake pipe 4, water intake hole 401, geotextile 402, horizontal connecting steel pipe 5, drainage outlet 501, horizontal water intake pipe 6, seepage hole 601, filter layer 7, wire mesh layer 701, geotextile layer 702, shotcrete layer 8, steel mesh 801, secondary lining layer 9, waterproof layer 10, reinforcing bar 11, drainage pipe 12, central drainage ditch 13, vertical drainage channel 14, sealing layer 15, building sealant 1501, rubber strip 1502, plastic hose 16, I-beam 17, horizontal reinforcing bar 18. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the following embodiments are merely illustrative examples of the present invention, but the scope of protection of the present invention is not limited thereto. The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides an integrated drainage support structure suitable for tunnels in water-rich fractured zones. Please refer to [link / reference]. Figures 1 to 6 It includes a primary shotcrete layer 2, a secondary shotcrete layer 8, a waterproof layer 10, a secondary lining layer 9, a number of I-beam pairs 3 evenly arranged at certain intervals along the tunnel direction, a horizontal connecting steel pipe 5 that is horizontally connected between the number of I-beam pairs 3, a reinforcing rib 11 welded between the inner flanges of the I-beam pairs 3, a filter layer 7, a vertical water pipe 4, and a horizontal water pipe 6.

[0034] In this configuration, several H-beam pairs 3 are cast within the secondary shotcrete layer 8, with their outer surfaces abutting against the primary shotcrete layer 2, to directly bear the surrounding rock pressure. Each H-beam pair 3 is formed by two identical H-beams with a pre-existing permeable gap 301 between their flanges and joined closely together at their webs, thus creating a vertical drainage channel 14 inside the H-beam pair 3. A filter layer 7 is positioned between the outer flange of the H-beam pair 3 and the primary shotcrete layer 2. A sealing layer 15 fills the permeable gap 301 between the inner flanges of the H-beam pair 3. Vertical water pipes 4 are arranged along the cross-section of the tunnel where the H-beam pair 3 is located, with one end of each vertical water pipe passing through… The initial shotcrete layer 2 extends obliquely upward into the tunnel soil, and the other end passes through the filter layer 7 and the water-permeable gap 301 between the outer flange plate and is inserted into the interior of the I-beam pair 3. The transverse connecting steel pipe 5 has a drain outlet 501 at the position where it penetrates into the interior of the I-beam pair 3. The drainage direction of the drain outlet 501 is the same as the drainage direction of the vertical drainage channel 14. The transverse water diversion pipe 6 is correspondingly set on the tunnel wall outside the transverse connecting steel pipe 5. One end of the transverse water diversion pipe 6 passes through the initial shotcrete layer 2 and extends obliquely upward into the tunnel soil, while the other end protrudes outside the initial shotcrete layer 2 and is connected to the transverse connecting steel pipe 5 outside the I-beam pair 3 through a plastic hose 16.

[0035] In existing technologies, the initial shotcrete layer 2, the secondary shotcrete layer 8, the waterproof layer 10, and the secondary lining layer 9 are common structures in tunnel support systems. The initial shotcrete layer 2 and the secondary shotcrete layer 8, together with the steel arch frame, form the initial support. Figure 1 As shown, the steel arch frame is usually installed after the initial shotcrete layer 2 is completed. It is assembled by connecting several I-beams 17 along the tunnel direction through transverse reinforcing bars 18. Compared with the above-mentioned prior art, the innovation of this utility model is as follows:

[0036] Firstly, this invention transforms single H-beams into pairs of H-beams joined together. This allows two identical H-beams to have a permeable gap 301 between their flanges and be joined closely together on their webs. This creates a vertical drainage channel within the H-beam pair 3, eliminating the need for a separate vertical drainage pipe. To ensure the drainage performance of the vertical drainage channel, this invention fills the permeable gap 301 between the inner flanges of the H-beam pair 3 with a sealing layer 15. This prevents water from seeping out through the permeable gap 301 between the inner flanges. However, this invention does not seal the permeable gap between the outer flanges of the H-beam pair 3. The water gap 301 allows water accumulated in the soil around the tunnel to enter the vertical drainage channel through the outer water-permeable gap 301. Furthermore, by setting up a vertical water inlet pipe 4, with one end extending into the tunnel soil and the other end inserted into the interior of the I-beam pair 3, the accumulated water near the tunnel surrounding rock can be better guided and collected into the vertical drainage channel. In addition, a filter layer 7 is provided on the side of the I-beam pair 3 that abuts against the initial sprayed concrete layer 2, thereby filtering the water that seeps into the vertical drainage channel and preventing the water-permeable gap 301 between the outer flanges of the I-beam pair 3 and the vertical drainage channel from being blocked.

[0037] Secondly, this utility model replaces the transverse steel bars in the traditional steel arch frame with a horizontal connecting steel pipe 5 that runs through the I-beams 3. Since the horizontal connecting steel pipe 5 connects the interior of each I-beam 3, that is, connects each vertical drainage channel, the horizontal connecting steel pipe 5 actually plays the role of horizontal drainage, thus eliminating the need for construction of horizontal drainage blind pipes. Furthermore, this utility model has a horizontal water diversion pipe 6 connected to the horizontal connecting steel pipe 5, which can divert the accumulated water in the tunnel soil into the horizontal connecting steel pipe, and then flow into the vertical drainage channel through the drain outlet 501.

[0038] In summary, this utility model, based on the original steel arch frame structure design, eliminates the need for additional cutting or deformation of the I-beams. It cleverly modifies the splicing method of the original steel arch frame, allowing adjacent I-beams to be assembled with pre-reserved water-permeable gaps to form I-beam pairs. The water-permeable gaps on the inner side of the I-beam pairs are sealed, but the water-permeable gaps on the outer side are not sealed; instead, a filter layer is installed. This creates a vertical drainage channel within the I-beam pairs, and vertical water inlets connect to this channel, eliminating the need for traditional vertical drainage blind pipes. Simultaneously, this utility model connects the I-beam pairs with horizontal steel pipes and connects them with horizontal water inlets, forming a horizontal drainage channel, further eliminating the need for traditional horizontal drainage blind pipes. This innovative design not only improves the structural integrity of the I-beams but also... The steel pairs and horizontal connecting steel pipes can be connected into an integral structure to perform the support function of traditional steel arch frames, while also providing vertical and horizontal drainage functions. This eliminates the need for construction of vertical and horizontal drainage blind pipes, saving procedures and shortening construction time. In addition, this utility model can achieve support and drainage functions immediately after the installation of the I-beam pairs, horizontal connecting steel pipes, horizontal water diversion pipes, and vertical water diversion pipes, without waiting for the completion of the secondary lining layer. Therefore, the integrated drainage support structure of this utility model has better timeliness and can more flexibly meet the drainage needs in the construction of tunnels in water-rich fractured zones. Furthermore, the drainage channel of this utility model is formed by connecting and assembling I-beam pairs and horizontal connecting steel pipes, which can withstand greater pressure and mechanical impact, and is not easily damaged or failed during subsequent secondary lining construction, effectively ensuring the drainage of tunnel seepage.

[0039] To prevent the H-beams from corroding the internal drainage water, in a preferred embodiment, the inner surface of the H-beam pair 3, i.e., the web surface at the joint of the H-beams in the H-beam pair 3, is coated with an isolation protective layer 302; preferably, the isolation protective layer 302 is made of epoxy resin coatings such as epoxy zinc primer or epoxy zinc phosphate anti-rust primer, or is made of fluorocarbon topcoat.

[0040] Furthermore, in a preferred real-time scheme, the vertical water pipe 4 and the horizontal water pipe 6 located in the tunnel soil are provided with a number of water inlet holes 401 and wrapped with geotextile 402; based on this arrangement, the number of water inlet holes 401 can facilitate the smoother and faster flow of water from the soil around the tunnel through the vertical water pipe 4 or the horizontal water pipe to the drainage channel, while the wrapped geotextile can prevent gravel, soil debris, etc. from clogging the water inlet holes or pipes.

[0041] Furthermore, in a preferred real-time embodiment, the filter layer 7 includes a wire mesh layer 701 and a geotextile layer 702 laid sequentially from the outside to the inside on the surface of the initial shotcrete layer 2; wherein, the geotextile layer 702 is laid directly on the surface of the initial shotcrete layer 2, and is composed of 2-4 layers of geotextile, mainly serving a filtering function; the wire mesh layer 701 covers the surface of the geotextile layer 702 and is anchored and tensioned on the initial shotcrete layer 2 to flatly fix the geotextile layer 702 on the surface of the initial shotcrete layer 2.

[0042] In order to ensure that the filter layer 7 can completely cover the permeable gap 301 and cover the contact surface between the I-beam pair 3 and the initial shotcrete layer 2, in a preferred real-time embodiment, the width of the filter layer 7 is 1.2-1.5 times the width of the I-beam pair 3, and the permeable gap 301 of the I-beam pair 3 is located on the circumferential centerline of the filter layer 7.

[0043] In the I-beam pair 3, the permeable gaps 301 on both sides of the flange plate have the same width. Since the permeable gaps 301 on the outer flange plate need to be sealed, while the permeable gaps 301 on the inner flange plate need to be connected to vertical water pipes and allow some seepage of tunnel soil, the width of the permeable gaps 301 should not be too large or too small. Furthermore, in a preferred real-time scheme, the width of the permeable gaps 301 is 2-4 cm, and the outer diameter of the water pipe 4 is slightly smaller than the width of the permeable gaps 301.

[0044] Furthermore, in a preferred real-time scheme, the spacing between adjacent I-beam pairs 3 is controlled to be 0.5-0.8m.

[0045] Furthermore, in a preferred real-time solution, the integrated drainage support structure of this utility model also includes a drainage pipe 12 pre-embedded in the tunnel ground. One end of the drainage pipe 12 is connected to the drainage outlet at the bottom of the I-beam 3, and the other end is connected to the central drainage ditch 13.

[0046] In order to better connect the sprayed concrete layer 8 with the I-beam pair 3 and the cross steel pipe 5 into an integral structure, in a preferred real-time scheme, a steel mesh 801 is provided inside the sprayed concrete layer 8, and the steel mesh 801 is welded to the I-beam pair 3 and the cross steel pipe 5.

[0047] Example 2

[0048] This embodiment provides a construction method for the integrated drainage support structure applicable to tunnels in water-rich fractured zones as described in Embodiment 1, specifically including the following steps:

[0049] S1. Pre-support is carried out before tunnel excavation. Usually, when carrying out pre-support, the construction unit needs to conduct geological exploration of the tunnel construction area and collect various pre-water exploration data, including but not limited to ground radar, ultrasonic detection, resistivity imaging, etc. Then, based on the pre-water exploration data, a suitable pre-support method is selected. Pre-support methods usually include grouting reinforcement, pre-anchor bolts, combined support, etc.

[0050] S2. After the tunnel excavation is completed according to the advance, spray concrete is applied to the exposed surrounding rock on the tunnel wall to form the initial sprayed concrete layer 2, in order to seal the rock surface cracks and prevent the surrounding rock from weathering and loosening. Specifically, the initial sprayed concrete layer 2 is made of concrete with a strength grade ≥ C20 and sprayed in layers. Before spraying, the rock wall needs to be washed with high-pressure air or water to remove loose stones and dust. The thickness of each layer is ≤100mm. The next layer needs to be sprayed after the previous layer has set. After 2 hours of setting, water curing is required.

[0051] S3. Mark the installation position of the I-beam pair 3 on the initial shotcrete layer 2, and construct the filter layer 7 at the installation position of the I-beam pair 3; mark the drilling position of the vertical water pipe 4 on the filter layer 7, and then drill holes to install the vertical water pipe 4, so that one end of the vertical water pipe 4 is inserted into the drilled hole and the other end is exposed outside the filter layer 7.

[0052] S4. Install H-beam pairs 3 one by one along the tunnel excavation direction. When installing H-beam pairs 3, support two H-beams of the same specification on both sides of the vertical water inlet pipe 4. Then, slowly bring the H-beams together and splice them closely through their webs, while controlling the water permeability gap 301 reserved between the flange plates of the two H-beams so that the protruding end of the vertical water inlet pipe 4 can pass through the water permeability gap 301 between the outer flange plates and be inserted into the interior of the H-beam pair 3. Then, fill the water permeability gap 301 between the inner flange plates with the sealing layer 15 and weld several reinforcements. The reinforcing rib 303 is used to strengthen the connection, and then the I-beam 3 is anchored in the tunnel. The sealing layer 15 can be made by using rubber strip 1502 and building sealant 1501 to seal the water-permeable gap 301. Specifically, a rubber strip slightly larger than the size of the water-permeable gap 301 is first inserted into the water-permeable gap 301, and then building sealant is filled into the gap between the rubber strip and the water-permeable gap 301 for sealing. In order to facilitate the through connection of the transverse steel pipe 5, holes can be pre-drilled at the required positions on both sides of the web of the I-beam 3.

[0053] S5. At a suitable position on the horizontal connecting steel pipe 5, a drain outlet 501 corresponding to the I-beam pair 3 is opened, and an interface for the horizontal water inlet pipe 6 is reserved. The horizontal connecting steel pipe 5 is sealed and connected to all the I-beam pairs 3 within the excavation advance, so that each drain outlet 501 is exactly located inside the corresponding I-beam pair 3. Then, a hole is drilled on the tunnel wall outside the horizontal connecting steel pipe 5, and then the horizontal water inlet pipe 6 is installed, so that one end of the horizontal water inlet pipe 6 is inserted into the drilled hole, and the other end is exposed outside the initial shotcrete layer 2 and connected to the reserved interface of the horizontal water inlet pipe 6 through a plastic hose. For ease of installation, the horizontal connecting steel pipe 5 can be made of multiple steel pipe sections spliced ​​on site.

[0054] S6. A drainage pipe 12 is pre-buried in the tunnel ground so that one end of the drainage pipe 12 is connected to the drainage outlet at the bottom of the I-beam 3, and the other end is connected to the central drainage ditch 13.

[0055] S7. Install steel mesh 801, weld steel mesh 801 to I-beam 3 and cross steel pipe 5, and then spray concrete to form sprayed concrete layer 8.

[0056] S8. Apply a waterproof layer 10 to the surface of the sprayed concrete layer 8, then tie the secondary lining reinforcement and pour the secondary lining concrete to form a continuous and closed secondary lining layer 9.

Claims

1. An integrated drainage support structure suitable for tunnels in water-rich fractured zones, comprising an initial shotcrete layer, a secondary shotcrete layer, a waterproof layer, and a secondary lining layer disposed on the tunnel wall, characterized in that, Also includes: Several pairs of I-beams are evenly spaced along the tunnel direction, horizontally connected steel pipes are connected between the pairs of I-beams, reinforcing ribs are welded between the inner flanges of the I-beams, filter layer, vertical water pipes, and horizontal water pipes. Several H-beams are cast into a secondary shotcrete layer, with their outer surfaces abutting against the primary shotcrete layer to directly bear the surrounding rock pressure. Each H-beam pair is formed by two identical H-beams with a permeable gap between their flanges and joined closely together at their webs, creating a vertical drainage channel within the H-beam pair. A filter layer is positioned between the outer flange of the H-beam pair and the primary shotcrete layer. A sealing layer fills the permeable gap between the inner flanges of the H-beam pair. Vertical water pipes are arranged along the cross-section of the tunnel where the H-beam pair is located. One end of the vertical water inlet pipe extends obliquely upward through the initial shotcrete layer into the tunnel soil, and the other end passes through the permeable gap between the filter layer and the outer flange plate to be inserted into the interior of the I-beam pair; the horizontal connecting steel pipe has a drain outlet at the position where it penetrates into the interior of the I-beam pair; the horizontal water inlet pipe is correspondingly set on the tunnel wall outside the horizontal connecting steel pipe, and one end of the horizontal water inlet pipe extends obliquely upward through the initial shotcrete layer into the tunnel soil, while the other end protrudes outside the initial shotcrete layer and is connected to the horizontal connecting steel pipe outside the I-beam pair through a plastic hose.

2. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The internal surface of the I-beam, specifically the web surface at the joint between the I-beams, is coated with an isolation and protective layer.

3. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The vertical and horizontal water pipes located within the tunnel soil are equipped with several water inlets and are wrapped with geotextile.

4. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The filter layer includes a wire mesh layer and a geotextile layer laid sequentially on the surface of the initial sprayed concrete layer from the outside to the inside.

5. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The width of the filter layer is 1.2-1.5 times the width of the I-beam pair, and the water-permeable gap of the I-beam pair is located on the circumferential centerline of the filter layer.

6. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The width of the permeable gap is 3-4 cm, and the outer diameter of the vertical water inlet pipe is smaller than the width of the permeable gap.

7. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The spacing between adjacent pairs of I-beams is controlled to be 0.5-0.8m.

8. The integrated drainage support structure for tunnels in water-rich fractured zones as described in claim 1, characterized in that, The sprayed concrete layer is reinforced with a steel mesh, which is welded to the I-beams and cross steel pipes.

9. An integrated drainage support structure suitable for tunnels in water-rich fractured zones as described in claim 1, characterized in that, It also includes drainage pipes pre-buried in the tunnel floor, with one end of the drainage pipe connected to the drainage outlet at the bottom of the I-beam and the other end connected to the central drainage ditch.

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