A method for coordinated control of yielding and pressure of floor heave of high-stress water-rich soft rock tunnel

Abstract

The application relates to the technical field of tunnel soft rock supporting, in particular to a high-stress water-rich soft rock tunnel floor heave yielding and cooperative control method. The control method is applicable to the scene that an inverted arch is not arranged under a tunnel floor or the depth of the inverted arch is less than one tenth of the tunnel span; the control method adopts a deep grouting and shallow grouting combined mode, a deep grouting closed layer is formed through deep grouting first, the deep grouting closed layer blocks the upward seepage of underground water, and provides a stable solidification environment for shallow grouting; the shallow grouting forms a high-strength shallow grouting reinforced layer under the protection of the deep closed layer. The deep grouting closed layer and the shallow grouting reinforced layer can cooperate, the deep grouting closed layer bears the water-blocking and stress diffusion functions, and the shallow grouting reinforced layer bears the anti-deformation function, at this time, the shallow grouting reinforced layer forms an inverted arch structure similar to a tunnel, so that the anti-deformation capacity of the tunnel floor is greatly improved.

Description

Technical Field

[0001] This application relates to the field of tunnel soft rock support technology, and in particular to a method for coordinated control of bottom heave and pressure relief in high-stress, water-rich soft rock tunnels. Background Technology

[0002] When deep-buried tunnels traverse soft rock strata, the coupling effect of high ground stress and groundwater often triggers severe floor heave disasters. Unlike mine roadways, tunnel engineering is characterized by large cross-sections (typically ≥50m²), flat shapes (width-to-height ratio ≥1.2), long service lives (decades to centuries), and strict deformation control (usually requiring floor heave ≤100mm). More critically, many operating tunnels were constructed without floor inverts, or with invert depths less than 1 / 10 of the tunnel span, causing the floor to directly bear the pressure of high-level ground stress, making floor heave particularly prominent. Existing methods for controlling tunnel floor heave mainly employ grouting reinforcement, but in high-stress, water-rich soft rock, the stress is particularly pronounced, severely blocking the grout diffusion path; moreover, when the surrounding rock becomes cemented, the grout cannot effectively diffuse and solidify, failing to fundamentally solve the problem of tunnel floor heave.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this application is to provide a method for coordinated control of bottom heave and pressure relief in high-stress, water-rich soft rock tunnels, in order to solve or alleviate the problems existing in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: A method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels, the method comprising the following steps: Step 1: Drill deep grouting holes from the bottom of the tunnel down to the deep intact soft rock, and inject waterproof grouting material into the deep intact soft rock through the grouting holes to form a deep grouting sealing layer. Step 2: Perform pressure relief operations inside the deep grouting sealing layer to release the surrounding rock stress, and reshape the stress concentration zone around the pressure relief operation to form a post-pressure relief stress concentration zone. Step 3: Drill shallow grouting holes from the bottom of the tunnel downwards. The shallow grouting holes are located inside the deep grouting sealing layer. Inject grouting material into the shallow grouting holes to perform shallow grouting to form a shallow grouting reinforcement layer. Step 4: Drill foam grouting holes from the bottom of the tunnel downwards. The foam grouting holes are located inside the shallow grouting reinforcement layer. Foam concrete is injected into the foam grouting holes to form a foam concrete buffer layer. Step 5: Install anchor bolts and anchor cables on the base plate. The anchor bolts penetrate the foamed concrete buffer layer and are anchored in the shallow grouting reinforcement layer. The anchor cables penetrate the foamed concrete buffer layer and the shallow grouting reinforcement layer and are anchored in the deep grouting sealing layer. Step 6: Erect a fully enclosed arch frame inside the tunnel and spray a concrete sealing layer inside the tunnel.

[0006] In the above-described high-stress, water-rich, soft rock tunnel bottom drum pressure relief and coordinated control method, preferably, the pressure relief operation involves drilling pressure relief holes on both sides of the bottom plate, with a set inclination angle between the pressure relief holes and the horizontal plane, and the pressure relief holes extending to the stress concentration area before pressure relief, with the deep grouting sealing layer located outside the stress concentration area before pressure relief.

[0007] In the above-described high-stress, water-rich, soft rock tunnel bottom drum pressure relief collaborative control method, preferably, in step 2, a grooving operation is first performed at the bottom of the pressure relief hole. The grooving operation involves extending the cutting part of a high-pressure water jet cutting device into the drilled pressure relief hole, using high-pressure water jet to cut a grooving in the drill hole, and the grooves in adjacent pressure relief holes are interconnected.

[0008] In the above-described high-stress, water-rich, soft rock tunnel bottom heave pressure relief and coordinated control method, preferably, in step 2, after the grooving operation in the pressure relief hole is completed, the pressure relief hole is cleaned, and then blasting operation is carried out. The blasting operation involves filling the pressure relief hole with explosives and blasting it, wherein the blasting point where the explosives are filled in the pressure relief hole is located above the bottom grooving of the pressure relief hole.

[0009] In the above-described high-stress, water-rich, soft rock tunnel bottom drum pressure relief and coordinated control method, preferably, the pressure relief hole adopts a decoupled charging structure in blasting operations.

[0010] In the above-described high-stress, water-rich, soft rock tunnel bottom heave pressure relief and coordinated control method, preferably, before deep grouting in step 1, a pre-grouting and grout-stopping process is added. Specifically, a borehole is first drilled to the periphery of the preset deep grouting sealing layer, and low-pressure grouting is performed through the borehole to form a grout-stopping curtain.

[0011] In the above-described method for controlling the pressure relief of the bottom heave in high-stress, water-rich soft rock tunnels, preferably, in step 3, the shallow grouting adopts the splitting grouting method, and an expansion agent is added to the grouting fluid of the shallow grouting.

[0012] In the above-described method for controlling the pressure relief of the bottom heave in high-stress, water-rich soft rock tunnels, preferably, in step 4, the dry density of the foamed concrete ranges from 300 to 800 kg / m³, and the compressive strength ranges from 0.5 to 3.0 MPa.

[0013] In the above-described method for controlling the pressure relief of the bottom heave in high-stress, water-rich soft rock tunnels, preferably, in step 5, anchor bolts and anchor cables are arranged alternately, and both anchor bolts and anchor cables need to be prestressed. The prestress value ranges from 50 to 150 kN, and the spacing between anchor bolts and anchor cables ranges from 0.8 to 1.5 m.

[0014] In the above-described high-stress, water-rich, soft rock tunnel bottom drum pressure relief collaborative control method, preferably, in step 6, an elastic block is filled between the bottom of the fully enclosed arch frame and the bottom plate to form a secondary pressure relief space.

[0015] Compared with the closest prior art, the technical solution of this application has the following beneficial effects: This control method is applicable to scenarios where no invert arch is installed beneath the tunnel floor or the invert arch depth is less than one-tenth of the tunnel span. Specifically, this method combines deep grouting with shallow grouting. First, deep grouting forms a deep grout sealing layer, which blocks the upward seepage of groundwater and provides a stable solidification environment for shallow grouting. Under the protection of the deep sealing layer, shallow grouting forms a high-strength shallow grout reinforcement layer. The deep grout sealing layer and the shallow grout reinforcement layer work synergistically. The deep grout sealing layer provides water isolation and stress diffusion, while the shallow grout reinforcement layer provides deformation resistance. At this point, the shallow grout reinforcement layer forms an invert arch structure similar to that of the tunnel, thereby greatly improving the deformation resistance of the tunnel floor. Compared with conventionally reinforced tunnels, tunnels treated with this method show a significant reduction in floor heave, greatly improving the long-term stability of the tunnel. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein: Figure 1 This is a cross-sectional schematic diagram of tunnel floor heave treatment according to some embodiments of this application; Figure 2 This is a top view schematic diagram of a tunnel decompression operation according to some embodiments of this application.

[0017] Explanation of reference numerals in the attached figures: 1. Tunnel; 2. Blasting point; 3. Cutting groove; 4. Stress concentration zone before pressure relief; 5. Stress concentration zone after pressure relief; 6. Anchor bolt; 7. Anchor cable; 8. Deep grouting sealing layer; 9. Shallow grouting reinforcement layer; 10. Foamed concrete buffer layer; 11. Fully enclosed arch frame; 12. Pressure relief hole. Detailed Implementation

[0018] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of interpretation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature represented or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0019] In the following description, the terms "first / second / third" are used merely to distinguish similar objects and do not represent a specific order of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to limit this disclosure.

[0021] In the description of this application, the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0022] The present application will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0023] According to specific embodiments of this application, such as Figure 1-2 As shown, this application provides a method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels. The control method includes the following steps: Step 1: Drill deep grouting holes from the bottom slab of tunnel 1 down to the deep intact soft rock, and inject waterproof grouting material into the deep intact soft rock through the grouting holes to form a deep grouting sealing layer 8; In this embodiment, the waterproof grouting material can be selected from cement-water glass double liquid grout or polyurethane grouting material and other grouting materials with waterproof properties.

[0024] Step 2: Perform pressure relief operation inside the deep grouting sealing layer 8 to release the surrounding rock stress, and reshape the stress concentration area around the pressure relief operation to form the post-pressure relief stress concentration area 5. Step 3: Drill shallow grouting holes downward from the bottom slab of tunnel 1. The shallow grouting holes are located inside the deep grouting sealing layer 8. Grouting material is injected into the shallow grouting holes to perform shallow grouting to form a shallow grouting reinforcement layer 9. In this embodiment, high-strength grouting material can be used for shallow grouting, and its compressive strength after solidification is greater than that of the foamed concrete used in step 4.

[0025] Step 4: Drill foam grouting holes from the bottom slab of tunnel 1 downwards. The foam grouting holes are located inside the shallow grouting reinforcement layer 9. Foam concrete is injected into the foam grouting holes to form a foam concrete buffer layer 10. Step 5: Install anchor bolts 6 and anchor cables 7 on the base plate. Anchor bolts 6 penetrate the foamed concrete buffer layer 10 and are anchored in the shallow grouting reinforcement layer 9. Anchor cables 7 penetrate the foamed concrete buffer layer 10 and the shallow grouting reinforcement layer 9 and are anchored in the deep grouting sealing layer 8. Step 6: Erect a fully enclosed arch frame 11 inside tunnel 1 and spray a concrete sealing layer inside tunnel 1.

[0026] This control method is applicable to scenarios where no invert arch is installed below the floor slab of Tunnel 1, or the depth of the invert arch is less than one-tenth of the span of Tunnel 1. Specifically, this control method combines deep grouting and shallow grouting. First, deep grouting forms a deep grouting sealing layer 8, which blocks the upward seepage of groundwater and provides a stable solidification environment for shallow grouting. Under the protection of the deep sealing layer, shallow grouting forms a high-strength shallow grouting reinforcement layer 9. The deep grouting sealing layer 8 and the shallow grouting reinforcement layer 9 work together. The deep grouting sealing layer 8 provides water isolation and stress diffusion, while the shallow grouting reinforcement layer 9 provides deformation resistance. At this point, the shallow grouting reinforcement layer 9 forms an invert arch structure similar to that of Tunnel 1, thereby greatly improving the deformation resistance of the floor slab of Tunnel 1. Compared with conventionally reinforced Tunnel 1, Tunnel 1 treated with this control method shows a significant reduction in floor bulging, greatly improving the long-term stability of Tunnel 1.

[0027] In this process, the network of fissures created by pressure relief within the surrounding rock after deep grouting provides an efficient diffusion channel for subsequent grouting, solving the technical challenge of grout penetration in high-stress, dense surrounding rock. Grouting, in turn, repairs the damage to the surrounding rock caused by blasting pressure relief and seals seepage paths. The complementary functions of pressure relief and grouting—"relieving stress without breaking it, and solidifying it without rigidity"—ensure the integrity and impermeability of the foundation rock while reducing stress.

[0028] Foamed concrete is injected into the inner side of the shallow grouting reinforcement layer 9 to form a foamed concrete buffer layer 10. The foamed concrete buffer layer 10 absorbs residual deformation energy with its high compressibility, significantly reducing the stress peak acting on the anchor bolt 6 and the arch frame, so that the support structure changes from a rigid compression state to a flexible compression relief state, and the service life of the support structure can be extended by 2 to 3 times.

[0029] The pressure relief operation involves drilling pressure relief holes 12 on both sides of the base plate. Each pressure relief hole 12 has a predetermined angle with the horizontal plane and extends beyond the stress concentration zone 4 before pressure relief. The deep grouting sealing layer 8 is located outside the stress concentration zone 4 before pressure relief. In this embodiment, by drilling pressure relief holes 12 and extending them to the stress concentration zone 4 before pressure relief, pressure relief is performed within the pressure relief holes 12, releasing the surrounding rock stress and reshaping the stress concentration zone. The reshaped stress concentration zone 5 after pressure relief is located further outward from the stress concentration zone 4 before pressure relief.

[0030] In this application, the deep grouting sealing layer 8 is pre-set close to the stress concentration zone 4 before pressure relief, so that the deep grouting sealing layer 8 is located between the stress concentration zone 4 before pressure relief and the stress concentration zone 5 after pressure relief. This setting has the following advantages: First, it avoids damage to the deep grouting sealing layer 8 during the stress remodeling process of the surrounding rock as much as possible. Second, since the tunnel 1 has a large span, the deep grouting sealing layer 8 is pre-constructed before the pressure relief operation to achieve preliminary sealing and isolation of deep water and stress. After the pressure relief operation, even if the deep grouting sealing layer 8 is affected by the stress remodeling of the surrounding rock, it can be remedied in the next step of shallow grouting. The grouting fluid of the shallow grouting will flow into the deep grouting sealing layer 8 to further reinforce the deep grouting sealing layer 8. At the same time, a shallow grouting reinforcement layer 9 is formed inside the deep grouting sealing layer 8, that is, a structure similar to the invert arch of the tunnel 1 is formed, which further provides the tunnel 1 with resistance to bottom heave deformation.

[0031] During the decompression operation, decompression holes 12 are drilled only near the two bottom feet of the tunnel 1 floor slab to the pre-decompression stress concentration zone 4 for decompression. This ensures that the decompression operation on both sides of the floor slab completely cuts off the pre-decompression stress concentration zone 4, thereby changing the stress distribution inside the surrounding rock and forming a new post-decompression stress concentration zone 5 around the pre-decompression stress concentration zone 4. The decompression holes 12 are drilled downwards at a certain angle near the two bottom feet of the tunnel 1 floor slab using a drilling rig. The angle of the decompression holes 12 can be between 25° and 35°. The decompression holes 12 can be repaired and used as installation holes for the anchor bolts 6 during the subsequent installation of the anchor bolts 6.

[0032] In step 2, a grooving operation is first performed at the bottom of the pressure relief hole 12. The grooving operation involves inserting the cutting part of a high-pressure water jet cutting device into the pressure relief hole 12 and using high-pressure water jets to cut a groove 3 in the borehole. The grooves 3 in adjacent pressure relief holes 12 are interconnected. In this embodiment, by inserting the cutting part of the high-pressure water jet cutting device into the borehole, the grooving point in the borehole is located near the stress concentration zone 4 before pressure relief. Then, the high-pressure water jet cutting device is activated to cut a groove 3 in the surrounding rock of the stress concentration zone 4 before pressure relief. The stress in the surrounding rock is released, and the stress concentration zone is reshaped. The grooves in adjacent boreholes overlap and are interconnected, so that the grooving operation forms an integrally connected fracture in the surrounding rock, which enables the subsequent grouting operation to form a complete grouting support body, which is beneficial to improving the overall structural strength of the support structure.

[0033] In step 2, after the grooving operation in the pressure relief hole 12 is completed, the pressure relief hole 12 is cleaned, and then a blasting operation is carried out. The blasting operation involves filling the pressure relief hole 12 with explosives and detonating it. The blasting point 2 where the explosives are filled in the pressure relief hole 12 is located above the grooving at the bottom of the pressure relief hole 12. In this embodiment, by filling the pressure relief hole 12 with explosives for blasting pressure relief, the stress concentration area can be reshaped, so that the stress concentration area 5 after pressure relief is transferred to a deeper range of the surrounding rock compared to the stress concentration area 4 before pressure relief. At the same time, the blasting pressure relief operation can also generate a fracture network in the surrounding rock, providing diffusion channels for subsequent grouting.

[0034] First, a groove is cut at the bottom of the pressure relief hole 12, and the blasting point 2, which is filled with explosives in the pressure relief hole 12, is located above the groove at the bottom of the pressure relief hole 12. This creates a physical isolation between the blasting point 2 and the deep grouting sealing layer 8, thereby reducing the efficiency of the blasting vibration transmitted to the deep grouting sealing layer 8. This reduces the impact of the blasting operation on the deep grouting sealing layer 8, thus ensuring the integrity and effectiveness of the deep grouting sealing layer 8 as much as possible.

[0035] In the blasting operation, the pressure relief hole 12 adopts a non-coupled charge structure. In this embodiment, the blasting operation is carried out after the deep grouting sealing layer 8 has been cured for at least 72 hours, wherein the spacing between pressure relief holes ranges from 0.6 to 1.2 m, and the charge amount per hole ranges from 50 to 200 g.

[0036] Before deep grouting in step 1, a pre-grouting and grout-stopping process is added. Specifically, boreholes are first drilled to the periphery of the pre-set deep grouting sealing layer 8, and low-pressure grouting is performed through the boreholes to form a grout-stopping curtain. In this embodiment, the pressure range of the low-pressure grouting in the pre-grouting is less than 1.5 MPa. By performing low-pressure pre-grouting on the outside of the pre-set deep grouting sealing layer 8, the grout forms a grout-stopping curtain on the outside of the pre-set deep grouting sealing layer 8, so as to minimize the impact of water in the surrounding rock on subsequent deep and shallow grouting operations, which is beneficial to ensuring that the support structure formed by the grouting operation has sufficient structural strength.

[0037] In step 3, shallow grouting employs the fracturing grouting method, and an expanding agent is added to the grouting fluid. In this embodiment, shallow grouting corresponds to areas with severe surrounding rock damage, and the severely damaged areas are reinforced through shallow grouting. The fracturing grouting method is more suitable for shallow grouting, as it has a wide penetration range, a large reinforcement range, and significantly improves the overall strength of the grout body. Simultaneously, adding an expanding agent to the grout body synergizes with the fracturing grouting method, effectively preventing shrinkage cracks during solidification, thus improving the density and overall structural strength of the grout body and enhancing its seepage prevention and water-stopping performance. The fracturing grouting pressure range is 2.0~4.0 MPa, the grouting fluid strength is ≥M30, and the expanding agent can be selected from calcium sulfoaluminate, calcium oxide, magnesium oxide, and calcium sulfoaluminate-calcium oxide composites, etc.

[0038] In step 4, the dry density of the foamed concrete ranges from 300 to 800 kg / m³, and its compressive strength ranges from 0.5 to 3.0 MPa. In this embodiment, the foamed concrete buffer layer 10 is adjacent to the shallow grouting reinforcement layer 9. The compressive strength of the foamed concrete buffer layer 10 is less than that of the shallow grouting reinforcement layer 9. It serves as a primary pressure relief space, directly facing the deformation impact of the shallow bearing layer, thus playing a role in primary pressure relief and buffering. The thickness of the foamed concrete buffer layer 10 ranges from 20 to 50 cm.

[0039] In step 5, anchor bolts 6 and anchor cables 7 are arranged alternately. Both anchor bolts 6 and anchor cables 7 require prestressing, with the prestressing value ranging from 50 to 150 kN. The spacing between anchor bolts 6 and anchor cables 7 ranges from 0.8 to 1.5 m. In this embodiment, prestressing is applied to both anchor bolts 6 and anchor cables 7 to better exert their anchoring capacity, thereby better anchoring the foamed concrete buffer layer 10, the shallow grouting reinforcement layer 9, and the deep grouting sealing layer 8 into a whole, thus improving the tunnel 1's resistance to floor heave deformation.

[0040] In step 6, elastic blocks are filled between the bottom of the fully enclosed arch frame 11 and the base plate to form a secondary pressure relief space. In this embodiment, the fully enclosed arch frame 11 adopts a U-shaped steel collapsible arch frame with a frame spacing range of 0.6~1.2m and a shotcrete thickness range of 50~100mm. A gap of 50~100mm is reserved between the bottom of the arch frame and the base plate. Elastic blocks, which can be rubber blocks, are filled in the gap between the bottom of the arch frame and the base plate. By filling the gap between the arch frame and the base plate with elastic blocks, a secondary pressure relief space is formed. This ensures that when the base plate is affected by large surrounding rock deformation, the foamed concrete buffer layer 10 below the base plate acts as a primary pressure relief space, and the foamed concrete buffer layer 10 is directly compressed and deformed. The elastic blocks, as a secondary pressure relief space, play a good buffering role when compressed, providing sufficient pressure relief space for the deformation of the base plate, ensuring that the arch frame inside the tunnel 1 will not be damaged or fail, and ensuring the safety of the tunnel 1 as much as possible.

[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels, characterized in that, The control method includes the following steps: Step 1: Drill deep grouting holes from the bottom of the tunnel down to the deep intact soft rock, and inject waterproof grouting material into the deep intact soft rock through the grouting holes to form a deep grouting sealing layer. Step 2: Perform pressure relief operations inside the deep grouting sealing layer to release the surrounding rock stress, and reshape the stress concentration zone around the pressure relief operation to form a post-pressure relief stress concentration zone. Step 3: Drill shallow grouting holes from the bottom of the tunnel downwards. The shallow grouting holes are located inside the deep grouting sealing layer. Inject grouting material into the shallow grouting holes to perform shallow grouting to form a shallow grouting reinforcement layer. Step 4: Drill foam grouting holes from the bottom of the tunnel downwards. The foam grouting holes are located inside the shallow grouting reinforcement layer. Foam concrete is injected into the foam grouting holes to form a foam concrete buffer layer. Step 5: Install anchor bolts and anchor cables on the base plate. The anchor bolts penetrate the foamed concrete buffer layer and are anchored in the shallow grouting reinforcement layer. The anchor cables penetrate the foamed concrete buffer layer and the shallow grouting reinforcement layer and are anchored in the deep grouting sealing layer. Step 6: Erect a fully enclosed arch frame inside the tunnel and spray a concrete sealing layer inside the tunnel.

2. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 1, characterized in that, The pressure relief operation involves drilling pressure relief holes on both sides of the base plate. The pressure relief holes have a set inclination angle with the horizontal plane, and the pressure relief holes extend to the stress concentration area before pressure relief. The deep grouting sealing layer is located on the periphery of the stress concentration area before pressure relief.

3. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 2, characterized in that, In step 2, a grooving operation is first performed at the bottom of the pressure relief hole. The grooving operation involves inserting the cutting part of the high-pressure water jet cutting device into the drilled pressure relief hole and using the high-pressure water jet to cut a grooving in the drilled hole. The grooves in adjacent pressure relief holes are interconnected.

4. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 3, characterized in that, In step 2, after the grooving operation in the pressure relief hole is completed, the pressure relief hole is cleaned, and then the blasting operation is carried out. The blasting operation involves filling the pressure relief hole with explosives and detonating it. The blasting point where the explosives are filled in the pressure relief hole is located above the grooving at the bottom of the pressure relief hole.

5. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 4, characterized in that, In blasting operations, the pressure relief holes adopt a non-coupled charging structure.

6. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 4, characterized in that, Before performing deep grouting in step 1, a pre-grouting and grout-stopping process is added. Specifically, a borehole is first drilled to the periphery of the pre-set deep grouting sealing layer, and low-pressure grouting is performed through the borehole to form a grout-stopping curtain.

7. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 6, characterized in that, In step 3, the shallow grouting adopts the splitting grouting method, and an expansion agent is added to the grouting fluid of the shallow grouting.

8. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 7, characterized in that, In step 4, the dry density of the foamed concrete ranges from 300 to 800 kg / m³, and the compressive strength ranges from 0.5 to 3.0 MPa.

9. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 8, characterized in that, In step 5, anchor bolts and anchor cables are arranged alternately. Both anchor bolts and anchor cables need to be prestressed. The prestress value ranges from 50 to 150 kN, and the spacing between anchor bolts and anchor cables ranges from 0.8 to 1.5 m.

10. The method for coordinated control of floor heave and pressure relief in high-stress, water-rich soft rock tunnels according to claim 9, characterized in that, In step 6, an elastic block is filled between the bottom of the fully enclosed arch frame and the base plate to form a secondary pressure relief space.

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