A soft rock roadway floor anti-deformation integrated treatment structure and construction method

Abstract

This invention discloses an integrated anti-deformation treatment structure and construction method for soft rock tunnel floor, comprising a seepage-proof isolation layer, a shallow grouting layer, and a deep grouting layer arranged sequentially from top to bottom. The seepage-proof isolation layer covers the shallow grouting layer and is fixedly and sealed to both sides of the tunnel. A concrete layer is laid on top of the seepage-proof isolation layer. Multiple sets of grouting anchors are regularly arranged inside the deep and shallow grouting layers. Each set of grouting anchors includes vertical anchors and ground anchors. The lower ends of the vertical and ground anchors are fixed to the rock mass below the deep grouting layer, and the upper ends are fixed to the upper part of the shallow grouting layer. Multiple pressure relief and cavity-forming holes are set along the centerline of the tunnel below the seepage-proof isolation layer and filled with flexible buffer material. This invention achieves full-process control of "graded grouting - anchor-grouting synergy - active pressure relief - seepage-proof isolation," improving the stability, durability, and construction efficiency of the floor treatment.

Description

Technical Field

[0001] This invention relates to the field of mine roadway management technology, specifically to an integrated anti-deformation management structure and construction method for soft rock roadway floor slabs. Background Technology

[0002] As my country's shallow resources are gradually depleted, mining deeper has become the direction of mineral resource extraction. As the mining depth increases, the geological environment of the tunnels becomes more and more complex. Under extreme geological conditions, the floor of soft rock tunnels frequently suffers from floor heave and deformation, which seriously affects the normal production of the mine and may even lead to safety accidents. Existing tunnel floor treatment technologies mainly include single or combined methods such as grouting reinforcement, anchor cable support, and floor pressure relief, but they still have many shortcomings: ① Traditional grouting technology uses a single grouting fluid, which cannot simultaneously consider permeability and deformation resistance. It is insufficient for filling small cracks in soft rock, and the rock mass is prone to secondary cracks due to stress release after grouting, resulting in poor durability of the reinforcement effect; ② Anchor cable support generally requires step-by-step construction, and the coordination between the anchor cable installation and grouting processes is poor, resulting in a lag in the formation of the support and surrounding rock bearing system, which cannot promptly suppress early deformation of the floor; ③ Existing floor pressure relief technologies such as pressure relief holes and top cutting pressure relief have poor long-term pressure relief effects, and the construction process is complex, which can easily cause secondary disturbance to the surrounding rock of the tunnel; ④ Existing floor pressure relief technologies do not pay enough attention to groundwater seepage prevention and have failed to form an integrated prevention and control technology system of "reinforcement-deformation resistance-seepage prevention". Groundwater continues to seep in and soften the floor rock layer, exacerbating floor heave deformation. Therefore, given the shortcomings of existing tunnel floor protection technologies, it is necessary to optimize them. Summary of the Invention

[0003] To address the shortcomings of the existing technologies, one objective of this invention is to propose an integrated anti-deformation treatment structure for soft rock tunnel floor slabs. This structure solves the problem that existing floor slab depressurization technologies do not fully consider the softening effect of surface water infiltration on the soft rock floor slab, thus causing deformation of the tunnel floor slab. Furthermore, the failure to form an effective prevention and control technology system of "reinforcement-deformation resistance-seepage prevention" leads to continuous infiltration of groundwater and softening of the floor slab rock layer, thereby exacerbating the problem of floor heave deformation.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] An integrated anti-deformation treatment structure for soft rock roadway floor includes a deep grouting layer located in the lower part of the floor, a shallow grouting layer located in the upper part of the floor, and a seepage prevention and isolation layer, which are arranged sequentially from top to bottom.

[0006] An anti-seepage isolation layer covers the upper surface of the shallow grouting layer, and the two sides of the anti-seepage isolation layer are fixedly and sealed to the lower part of the two sides of the roadway.

[0007] A concrete layer is laid on top of the seepage-proof isolation layer. The deep grouting layer and the shallow grouting layer have multiple sets of grouting anchors inside, which are regularly distributed at equal intervals along the extension direction of the roadway.

[0008] Each group of grouting anchor cables includes vertical anchor cables and ground anchor cables. There are at least two vertical anchor cables, which are located in the middle of the roadway. There are two ground anchor cables, which are located near the two sides of the roadway. The two ground anchor cables are arranged in a figure-eight shape on both sides of all the vertical anchor cables in the same group, and are distributed linearly with each of the vertical anchor cables in the same group.

[0009] Both the vertical anchor cable and the ground anchor cable are prestressed anchor cables. The lower ends of the vertical anchor cable and the ground anchor cable are fixed to the rock mass below the deep grouting layer, and the upper ends of the vertical anchor cable and the ground anchor cable are fixed to the upper part of the shallow grouting layer.

[0010] Multiple vertical pressure relief cavitation holes are provided below the seepage prevention isolation layer. All pressure relief cavitation holes are evenly distributed along the centerline of the roadway and are arranged at intervals with the vertical anchor cables. The interior of the pressure relief cavitation holes is filled with flexible buffer material.

[0011] Furthermore, the shallow grouting layer is an integral structure formed by injecting a composite grout of polyurethane and cement into the soft, weakly cemented mudstone located on the upper part of the base plate and solidifying it. The shallow grouting layer is located within a range of 0-2m from the upper surface of the base plate.

[0012] Furthermore, the deep grouting layer is an integral structure formed by pressure grouting inside the stable rock strata below the base plate.

[0013] The grouting fluid for the deep grouting layer is a two-component grout of ultrafine cement and water glass, and the deep grouting layer is located within a range of 2-5m from the upper surface of the base plate.

[0014] Furthermore, the seepage-proof isolation layer is composed of multiple waterproof membranes laid sequentially along the extension direction of the tunnel. The waterproof membranes are made of HDPE high-density polyethylene material and have a thickness of not less than 2mm.

[0015] The corresponding sections of any two adjacent waterproof membranes are overlapped and sealed together using a hot-melt process. The bottom surface of the waterproof membrane is connected to the upper surface of the shallow grouting layer using a hot-melt process.

[0016] Furthermore, the two sides of the waterproof membrane are bent upwards at 90° to form folded sections, and the outer wall of the folded sections of the waterproof membrane is sealed and fixed to the side wall of the tunnel.

[0017] The thickness of the concrete layer is 8-10cm, and it is formed by pouring C20 concrete mixed with 5% quick-setting agent and 3% waterproofing agent. The height difference between the upper end face of the folded part and the upper surface of the concrete layer is not less than 10cm.

[0018] Another objective of this invention is to propose a construction method for an integrated anti-deformation treatment structure for the floor slab of soft rock tunnels.

[0019] A construction method for an integrated anti-deformation treatment structure for soft rock roadway floor slabs, based on the aforementioned integrated anti-deformation treatment structure for soft rock roadway floor slabs, includes the following steps:

[0020] Step 1: Investigate the geological condition of the tunnel floor to obtain data on the thickness of the softened layer, the distribution of fissures, and the water seepage of the weakly cemented mudstone, and formulate specific construction plans accordingly.

[0021] Step 2: Drill multiple sets of deep grouting holes at equal intervals on the base plate. Each set of deep grouting holes includes four deep grouting holes distributed laterally. Remove the gravel from each deep grouting hole.

[0022] Step 3: Install anchor cables with grouting pipes inside each deep grouting hole. After fixing the lower end of the anchor cable to the bottom of the deep grouting hole, use tensioning equipment to tension each anchor cable and maintain the set tension prestress. Then, perform high-pressure grouting into the deep grouting hole.

[0023] After the grout in the deep grouting hole has initially set, it combines with the deep rock strata to form a deep grouting layer. Then, the excess anchor cable is cut off, and the top of the deep grouting hole is sealed with concrete.

[0024] Step 4: Drill multiple sets of shallow grouting holes at equal intervals on the bottom plate. Each set of shallow grouting holes and multiple sets of deep grouting holes are arranged alternately along the direction of the roadway extension. Each set of shallow grouting holes includes at least two shallow grouting holes that are distributed laterally at intervals. After that, remove the gravel from each shallow grouting hole.

[0025] Step 5: Use composite grout to perform pressure grouting on each shallow grouting hole. After the grouting in the shallow grouting hole is completed, use a sealing plug to seal the top of the shallow grouting hole.

[0026] Step 6: Drill multiple vertical pressure relief and cavity-forming holes along the centerline of the tunnel on the bottom plate. Multiple pressure relief and cavity-forming holes are alternately distributed with multiple sets of deep grouting holes. The bottom of the pressure relief and cavity-forming holes is located in the hard rock body below the deep grouting layer.

[0027] Remove the gravel from each pressure relief cavity, fill the cavity with flexible buffer material, and seal the cavity opening after the flexible buffer material has filled the entire cavity.

[0028] Step 7: Clean the upper surface of the shallow grouting layer. Then, lay a waterproof membrane on top of the shallow grouting layer. The bottom of the waterproof membrane is connected to the shallow grouting layer by a hot-melt process, and the two sides are also connected to the lower part of the two sides of the tunnel by a hot-melt process.

[0029] After the waterproof membrane is laid, C20 concrete is sprayed on top of the waterproof membrane and leveled. Then, the concrete layer on top of the waterproof membrane is left to stand for no less than 7 days. During this period, the deformation of the tunnel floor is monitored.

[0030] By adopting the above technical solution, the beneficial technical effects of the present invention are as follows:

[0031] 1. The shallow and deep sections of the tunnel floor are grouted in stages. The flexible grout in the shallow section adapts to the early deformation of the surrounding rock, while the high-strength grout in the deep section plays a role in reinforcement. This design achieves a better grouting effect.

[0032] 2. Grouting and anchoring are completed in tandem, significantly enhancing the deformation resistance of the base plate.

[0033] 3. Use mechanical cavity drilling equipment to drill pressure relief cavity holes inside the tunnel floor and fill them with flexible buffer material to prevent stress concentration in the rock strata below the tunnel floor from causing damage to the floor.

[0034] 4. This solution lays an anti-seepage isolation layer and a concrete layer on the surface of the roadway floor, which effectively blocks the seepage path of mine water and prevents the floor from softening when exposed to water. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to the present invention.

[0036] Figure 2 This is a cross-sectional schematic diagram of the present invention along the location of the shallow grouting hole.

[0037] Figure 3 This is a cross-sectional schematic diagram of the present invention along the location of the pressure relief cavity.

[0038] Figure 4 This is a construction status diagram of an integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to the present invention.

[0039] Figure 5 This is a partial top view of an integrated anti-deformation treatment structure for the floor of a soft rock tunnel according to the present invention.

[0040] The figure shows: 1. Deep grouting layer; 11. Deep grouting hole; 2. Shallow grouting layer; 21. Shallow grouting hole; 3. Anti-seepage isolation layer; 31. Folded section; 4. Concrete layer; 51. Vertical anchor cable; 52. Anchor cable; 53. Anchor plate; 6. Pressure relief cavity. Detailed Implementation

[0041] To make the advantages and technical solutions of the present invention clearer and more explicit, the present invention will be described in detail below with reference to specific embodiments.

[0042] Example 1, combined with Figures 1 to 5 An integrated anti-deformation treatment structure for soft rock tunnel floor is disclosed, applicable to tunnel floor treatment projects under complex geological conditions such as weakly cemented argillaceous soft rock and water-softening floor. The integrated anti-deformation treatment structure for soft rock tunnel floor includes a deep grouting layer 1 located in the lower part of the floor, a shallow grouting layer 2 located in the upper part of the floor, and a seepage-proof isolation layer 3. The seepage-proof isolation layer 3, shallow grouting layer 2, and deep grouting layer 1 are arranged sequentially from top to bottom. The shallow grouting layer 2 is also referred to as the shallow grouting zone, and the deep grouting layer 1 is also referred to as the deep grouting zone.

[0043] The shallow grouting layer 2 is an integral structure formed by injecting a composite grout of polyurethane and cement into the interior of the weakly cemented argillaceous soft rock located on the upper part of the floor using pressure grouting. The shallow grouting layer 2 is located within a range of 0-2m from the upper surface of the floor. Multiple sets of shallow grouting holes 21 are drilled at equal intervals along the extension direction of the tunnel floor. Each set of shallow grouting holes 21 includes at least two shallow grouting holes 21 arranged linearly at intervals along the cross-section of the tunnel. The shallow grouting holes 21 are vertically downward, with their lower ends passing through the interface between the weakly cemented argillaceous soft rock and the stable rock layer, reaching the interior of the stable rock layer.

[0044] During construction, after sealing the upper end of the shallow grouting hole 21, a pressure grouting device is used to inject the prepared polyurethane + cement composite grout. The row spacing of the shallow grouting holes 21 is 1.2m, the hole spacing of the same group of shallow grouting holes 21 is 1.5m, the hole depth of the shallow grouting holes 21 is 2.0-2.5m, and the grouting pressure is 1.5-2.0MPa. After grouting is completed, the composite grout fills the gaps of the argillaceous weakly cemented soft rock. After solidification, it combines with the softened rock layer to form a whole and is firmly bonded to the hard rock layer below. The grouting liquid of the shallow grouting layer 2 is a polyurethane + cement composite grout, which can ensure both rigidity and flexibility after solidification and has stronger resistance to deformation.

[0045] The seepage-proof isolation layer 3 covers the upper surface of the shallow grouting layer 2, and its two sides are fixedly and sealed to the lower sides of the tunnel. Specifically, the seepage-proof isolation layer 3 is composed of multiple waterproof membranes laid sequentially along the extension direction of the tunnel. The waterproof membranes are square rolls made of HDPE high-density polyethylene material, with a thickness of not less than 2mm, and a width greater than the width of the tunnel.

[0046] Corresponding sections of any two adjacent waterproof membrane sheets are overlapped and sealed together using a hot-melt process. The bottom surface of the waterproof membrane is connected to the upper surface of the shallow grouting layer 2 using a hot-melt process. Both sides of the waterproof membrane are bent upwards at 90° to form folded sections 31. The outer wall of the folded sections 31 of the waterproof membrane is sealed and fixed to the sidewall of the roadway. After pressure grouting and sealing of the deep grouting layer 1 and the shallow grouting layer 2, multiple waterproof membrane sheets are laid sequentially along the direction of the roadway. All the waterproof membrane sheets form an integral waterproof layer, preventing water from the surface of the roadway floor from seeping into the underlying argillaceous weakly cemented soft rock. Water will also not seep into the underlying argillaceous weakly cemented soft rock through the coal walls on both sides of the roadway, effectively preventing the shallow grouting layer 2 from absorbing water and expanding, thus avoiding bottom bulging.

[0047] A concrete layer 4, 8-10 cm thick, is laid on top of the seepage-proof isolation layer 3. The concrete layer 4 is formed by pouring C20 concrete mixed with 5% quick-setting agent and 3% waterproofing agent. The height difference between the upper surface of the folded portion 31 and the upper surface of the concrete layer 4 is no less than 10 cm. The concrete layer 4 and the waterproof membrane below it form a composite structure to achieve initial seepage prevention and surface curing.

[0048] The deep grouting layer 1 is an integral structure formed by pressure grouting inside the stable rock layer under the bottom plate. The grouting fluid of the deep grouting layer 1 is a two-liquid grout of ultrafine cement and water glass. The deep grouting layer 1 is located within a range of 2-5m from the upper surface of the bottom plate and is adjacent to and below the shallow grouting layer 2.

[0049] The deep grouting layer 1 and the shallow grouting layer 2 contain multiple sets of grouting anchors, which are regularly distributed at equal intervals along the extension direction of the roadway. Specifically, each set of grouting anchors includes vertical anchors 51 and ground anchors 52. There are two vertical anchors 51 located in the middle of the roadway, and two ground anchors 52 located near the two sides of the roadway. The two ground anchors 52 are arranged in a V-shape on both sides of all the vertical anchors 51 in the same set, and are linearly distributed with the vertical anchors 51 in the same set. The ground anchors 52 are arranged obliquely at the bottom of the two sides of the roadway, which plays a role in locking the sides and controlling the bottom, cutting off the slip line of the sides and bottom, and inhibiting the linkage between the bottom heave and the sides. Vertical anchors 51 are arranged in the middle of the roadway floor in a grid pattern, which plays a role in deep anchoring and strengthening the constraint, anchoring the shallow broken rock layers into the deep stable layer, forming the floor load-bearing skeleton.

[0050] Both the vertical anchor cable 51 and the ground anchor cable 52 are prestressed anchor cables. The lower ends of the vertical anchor cable 51 and the ground anchor cable 52 are fixed to the rock mass below the deep grouting layer 1, and the upper ends of the vertical anchor cable 51 and the ground anchor cable 52 are fixed to the upper part of the shallow grouting layer 2.

[0051] During construction, deep grouting holes 11 need to be drilled in the tunnel floor, with the same number and corresponding positions as the grouting anchor cables. This involves drilling multiple sets of deep grouting holes 11 along the tunnel's extension direction. Each set includes four deep grouting holes 11 arranged linearly at intervals. The two middle deep grouting holes 11 are vertically downwards, while the two on either side are vertically inclined at 45°. The spacing between any two adjacent sets of deep grouting holes 11 is 1.0m, and the spacing between deep grouting holes 11 within the same set is also 1.0m. The depth of the two middle deep grouting holes 11 is 6.0-6.2m, and the vertical depth of the two on either side is 7.0-7.2m. The upper end of each deep grouting hole 11 is a flared, stepped opening.

[0052] Two vertical anchor cables 51 are located in the two middle deep grouting holes 11, with the bottom of each anchor cable 51 fixed inside the deep grouting hole 11. Two anchor cables 52 are located in the two side deep grouting holes 11, with the bottom of each anchor cable 52 fixed inside the deep grouting hole 11. Each vertical anchor cable 51 and each anchor cable 52 is equipped with a grouting pipe and a set of anchors. The anchors are installed at the step position of the stepped opening at the upper end of the deep grouting hole 11.

[0053] After drilling each deep grouting hole 11 to the predetermined depth and cleaning out the debris inside, each vertical anchor cable 51 and each anchor cable 52 is installed inside the corresponding deep grouting hole 11. Then, atmospheric pressure grouting is first performed at the bottom of the deep grouting hole 11. After solidification, the anchor head at the lower end of the vertical anchor cable 51 or the anchor cable 52 is fixed to the stable rock layer at the bottom of the deep grouting hole 11.

[0054] Next, anchorages are installed at the upper ends of the deep grouting holes 11. The ends of the vertical anchor cables 51 or the anchor cables 52 pass through the anchor plates 53 of the anchorages. The anchor plates are embedded inside the upper ends of the deep grouting holes 11. The vertical anchor cables 51 or the anchor cables 52 are prestressed using a tensioning device. The prestress of the anchor cables is not less than 150kN. Then, clamps are used to fix the vertical anchor cables 51 or the anchor cables 52 to the anchor plates 52, and the excess parts are cut off. Pressure grouting is performed into the deep grouting holes 11 through the grouting holes on the anchor plates. The grouting pressure is 2.5-3.0MPa. After grouting is completed, the grouting holes on the anchor plates are sealed, and the upper ends of each deep grouting hole 11 are sealed with concrete. The first grouting inside the deep grouting hole 11 is performed under normal pressure to fix the anchor head of the anchor cable. The second grouting is performed under high pressure. The two-stage grouting process ensures that the filling is dense.

[0055] Below the seepage-proof isolation layer 3, multiple vertical pressure relief cavitation holes 6 are provided. All pressure relief cavitation holes 6 are evenly distributed along the centerline of the roadway and spaced apart from the vertical anchor cables 51. The spacing between the holes 6 is 1.2m, the depth of each hole is 8.0-10m, and the inner diameter is 30-40cm. They are constructed using hydraulic mechanical cavitation equipment. The interior of each pressure relief cavitation hole 6 is filled with a flexible buffer material 61. This flexible buffer material 61 is mainly a high-polymer flexible foam polyurethane flexible filling material, which absorbs the deformation stress of the surrounding rock and avoids stress concentration leading to deep rock strata compression and subsequent floor damage. During construction, after the pressure relief cavity drilling is completed, the hole is cleaned, and then the lower end of the pipe containing the filling material 61 is placed at the bottom of the cavity. The filling material is then added from the bottom of the pressure relief cavity 6 upwards. When the filling reaches the opening of the pressure relief cavity 6, the grouting pump is connected for grouting. When a large amount of grout leakage occurs, the grouting is stopped, and after standing for a period of time, a flexible sealing body is formed.

[0056] Example 2, combined with Figures 1 to 5 A construction method for an integrated anti-deformation treatment structure for soft rock roadway floor slabs, based on the integrated anti-deformation treatment structure for soft rock roadway floor slabs as described in Example 1, includes the following steps:

[0057] Step 1: Investigate the geological condition of the tunnel floor to obtain data on the thickness of the softened layer, the distribution of fissures, and the water seepage of the weakly cemented mudstone, and formulate specific construction plans accordingly.

[0058] Step 2: Drill multiple sets of deep grouting holes 11 at equal intervals on the bottom plate of the tunnel. Each set of deep grouting holes 11 includes four deep grouting holes 11 distributed laterally at intervals. Remove the gravel from each deep grouting hole 11.

[0059] Step 3: Install anchor cables with grouting pipes inside each deep grouting hole 11. After the lower end of the anchor cable is fixed to the bottom of the deep grouting hole 11, use tensioning equipment to tension each anchor cable and maintain the set tension prestress. Then, perform high-pressure grouting into the deep grouting hole 11.

[0060] After the grout in the deep grouting hole 11 has initially set, it combines with the deep rock strata to form the deep grouting layer 1. Then, the excess anchor cable is cut off, and the top of the deep grouting hole 11 is sealed with concrete.

[0061] Step 4: Drill multiple sets of shallow grouting holes 21 at equal intervals on the roadway floor. Each set of shallow grouting holes 21 and multiple sets of deep grouting holes 11 are arranged alternately along the roadway extension direction. Each set of shallow grouting holes 21 includes at least two shallow grouting holes 21 distributed laterally. After that, remove the gravel from each shallow grouting hole 21.

[0062] Step 5: Use composite grout to perform pressure grouting on each shallow grouting hole 21. After the grouting in the shallow grouting hole 21 is completed, use a sealing plug to seal the top of the shallow grouting hole 21.

[0063] Step 6: Drill multiple vertical pressure relief and cavity-forming holes 6 along the centerline of the tunnel on the bottom plate. The multiple pressure relief and cavity-forming holes 6 are alternately distributed with multiple sets of deep grouting holes 11. The bottom of the pressure relief and cavity-forming holes 6 is located in the hard rock body below the deep grouting layer 1.

[0064] Remove the gravel from each pressure relief cavity 6, fill the inside of the pressure relief cavity 6 with flexible buffer material, and seal the opening of each pressure relief cavity 6 after the flexible buffer material has filled the entire pressure relief cavity 6.

[0065] Step 7: Clean the upper surface of the shallow grouting layer 2. Then, lay a waterproof membrane on top of the shallow grouting layer 2. The bottom surface of the waterproof membrane is connected to the shallow grouting layer 2 by a hot-melt process, and the two sides are also connected to the lower part of the two sides of the tunnel by a hot-melt process.

[0066] After the waterproof membrane is laid, C20 concrete is sprayed on top of the waterproof membrane and leveled. Then, the concrete layer 4 on top of the waterproof membrane is left to stand for no less than 7 days. During this period, the deformation of the tunnel floor is monitored.

[0067] For any parts not mentioned in this invention, existing technologies can be used or referenced.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0069] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. An integrated anti-deformation treatment structure for the floor slab of soft rock tunnels, characterized in that, It includes a deep grouting layer located in the lower part of the base plate, a shallow grouting layer located in the upper part of the base plate, and a seepage prevention and isolation layer, which are arranged sequentially from top to bottom; An anti-seepage isolation layer covers the upper surface of the shallow grouting layer, and the two sides of the anti-seepage isolation layer are fixedly and sealed to the lower part of the two sides of the roadway, respectively. A concrete layer is laid on top of the seepage-proof isolation layer. The deep grouting layer and the shallow grouting layer have multiple sets of grouting anchors inside, which are regularly distributed at equal intervals along the extension direction of the roadway. Each group of grouting anchor cables includes vertical anchor cables and ground anchor cables. There are at least two vertical anchor cables, which are located in the middle of the roadway. There are two ground anchor cables, which are located near the two sides of the roadway. The two ground anchor cables are arranged in a figure-eight shape on both sides of all the vertical anchor cables in the same group, and are distributed linearly with each of the vertical anchor cables in the same group. Both the vertical anchor cable and the ground anchor cable are prestressed anchor cables. The lower ends of the vertical anchor cable and the ground anchor cable are fixed to the rock mass below the deep grouting layer, and the upper ends of the vertical anchor cable and the ground anchor cable are fixed to the upper part of the shallow grouting layer. Multiple vertical pressure relief cavitation holes are provided below the seepage prevention isolation layer. All pressure relief cavitation holes are evenly distributed along the centerline of the roadway and are arranged at intervals with the vertical anchor cables. The interior of the pressure relief cavitation holes is filled with flexible buffer material.

2. The integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to claim 1, characterized in that, The shallow grouting layer is an integral structure formed by injecting polyurethane and cement composite grout into the soft, weakly cemented mudstone located on the upper part of the base plate and solidifying it. The shallow grouting layer is located within a range of 0-2m from the upper surface of the base plate.

3. The integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to claim 1, characterized in that, The deep grouting layer is an integral structure formed by pressure grouting inside the stable rock strata below the base plate. The grouting fluid for the deep grouting layer is a two-component grout of ultrafine cement and water glass, and the deep grouting layer is located within a range of 2-5m from the upper surface of the base plate.

4. The integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to claim 1, characterized in that, The seepage-proof isolation layer is composed of multiple waterproof membranes laid sequentially along the extension direction of the tunnel. The waterproof membranes are made of HDPE high-density polyethylene material and have a thickness of not less than 2mm. The corresponding sections of any two adjacent waterproof membranes are overlapped and sealed together using a hot-melt process. The bottom surface of the waterproof membrane is connected to the upper surface of the shallow grouting layer using a hot-melt process.

5. The integrated anti-deformation treatment structure for the floor slab of a soft rock tunnel according to claim 4, characterized in that, The waterproof membrane is bent upwards at 90° on both sides to form folded sections, and the outer wall of the folded sections of the waterproof membrane is sealed and fixed to the side wall of the tunnel. The thickness of the concrete layer is 8-10cm, and it is formed by pouring C20 concrete mixed with 5% quick-setting agent and 3% waterproofing agent. The height difference between the upper end face of the folded part and the upper surface of the concrete layer is not less than 10cm.

6. A construction method for integrated anti-deformation treatment of soft rock roadway floor slab, based on the integrated anti-deformation treatment structure for soft rock roadway floor slab as described in any one of claims 1 to 5, characterized in that, The construction method includes the following steps; Step 1: Investigate the geological condition of the tunnel floor to obtain data on the thickness of the softened layer, the distribution of fissures, and the water seepage of the weakly cemented mudstone, and formulate specific construction plans accordingly. Step 2: Drill multiple sets of deep grouting holes at equal intervals on the base plate. Each set of deep grouting holes includes four deep grouting holes distributed laterally. Remove the gravel from each deep grouting hole. Step 3: Install anchor cables with grouting pipes inside each deep grouting hole. After fixing the lower end of the anchor cable to the bottom of the deep grouting hole, use tensioning equipment to tension each anchor cable and maintain the set tension prestress. Then, perform high-pressure grouting into the deep grouting hole. After the grout in the deep grouting hole has initially set, it combines with the deep rock strata to form a deep grouting layer. Then, the excess anchor cable is cut off, and the top of the deep grouting hole is sealed with concrete. Step 4: Drill multiple sets of shallow grouting holes at equal intervals on the bottom plate. Each set of shallow grouting holes and multiple sets of deep grouting holes are arranged alternately along the direction of the roadway extension. Each set of shallow grouting holes includes at least two shallow grouting holes that are distributed laterally at intervals. After that, remove the gravel from each shallow grouting hole. Step 5: Use composite grout to perform pressure grouting on each shallow grouting hole. After the grouting in the shallow grouting hole is completed, use a sealing plug to seal the top of the shallow grouting hole. Step 6: Drill multiple vertical pressure relief and cavity-forming holes along the centerline of the tunnel on the floor. These pressure relief and cavity-forming holes are alternately distributed with multiple sets of deep grouting holes. The bottom of the pressure relief and cavity-forming holes is located in the hard rock body below the deep grouting layer. Remove the gravel from each pressure relief cavity, fill the cavity with flexible buffer material, and seal the opening of each cavity after the flexible buffer material has filled the entire cavity. Step 7: Clean the upper surface of the shallow grouting layer. Then, lay a waterproof membrane on top of the shallow grouting layer. The bottom of the waterproof membrane is connected to the shallow grouting layer by a hot-melt process, and the two sides are also connected to the lower part of the two sides of the tunnel by a hot-melt process. After the waterproof membrane is laid, C20 concrete is sprayed on top of the waterproof membrane and leveled. Then, the concrete layer on top of the waterproof membrane is left to stand for no less than 7 days. During this period, the deformation of the tunnel floor is monitored.

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