A method for preventing floor heave in soft rock floorboards

Abstract

This invention discloses a method for preventing floor heave in soft rock floor slabs, comprising the following steps: excavating a hollow trench in the water-spraying section of the soft rock floor slab, and spraying grout to treat the trench walls; installing grouting anchors at intervals on the floor slab of the hollow trench, welding a steel pipe to the end of each anchor, laying a steel mesh at intervals on the steel pipe, and welding the steel mesh to the steel pipe; pouring concrete into the hollow trench and allowing it to solidify to form a concrete body, leaving a predetermined width between the hollow trench and the concrete body to form a pressure relief space 1; pouring a baffle above the pressure relief space 1 to connect the concrete body and the sidewalls of the hollow trench; laying a drainage grid on top of the concrete body, the drainage grid being flush with the tunnel floor slab and having a pressure relief space 2 between it and the concrete body; and drilling a drainage channel in the rock mass on one side of the hollow trench to connect the pressure relief space 2 and the drainage ditch. This method is simple, easy to implement, convenient to construct, economical, and efficient. It not only effectively controls floor heave in tunnels but also effectively prevents floor heave caused by expansion of the soft rock floor slab due to water spraying.

Description

Technical Field

[0001] This invention belongs to the field of coal mine safety management technology, and in particular relates to a method for preventing floor heave caused by water seepage from the roof in soft rock floor. Background Technology

[0002] During coal mine tunnel excavation, almost all tunnels experience varying degrees of floor heave, which is particularly noticeable in soft rock tunnels. When the soft rock floor is exposed to water from the tunnel roof, not only does water accumulate on the floor, making it difficult for pedestrians to walk, but prolonged soaking by the water can also cause the soft rock to expand and heave.

[0003] Currently, the most common methods for reinforcing the base slab are pouring concrete and grouting anchors or using inverted bottom arches. These methods can suppress bottom heave to some extent for a period of time, but the effect is not significant, especially when exposed to water spray, the effect is even worse, and maintenance is difficult. Therefore, there is an urgent need for a new treatment method to effectively prevent bottom heave caused by water spray from the top slab in soft rock base slabs. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for preventing floor heave in soft rock roadways. This method effectively removes water accumulation in the floor and has a significant preventive effect on floor heave in soft rock roadways. The method is simple, easy to implement, and convenient to construct, and has wide applicability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preventing floor heave in soft rock floor slabs includes the following steps: 1) In the water-spraying section of the soft rock base, excavate a hollow trench and spray grout the trench walls; 2) Install several grouting anchors at intervals on the bottom plate of the empty trench. A steel pipe is vertically welded to the end of each anchor. Multiple layers of steel mesh are laid on the steel pipe at intervals, and the steel mesh is welded to the steel pipe. 3) Pour concrete into the empty groove and let it solidify to form a concrete body. Leave a predetermined width between the two sides of the empty groove and the concrete body to form a pressure relief space 1. Pour a baffle above the pressure relief space 1 to connect the concrete body and the side wall of the empty groove. 4) Lay a drainage grid on top of the concrete structure, with the drainage grid flush with the tunnel floor and with a pressure relief space between it and the concrete structure. 5) Drill a diversion channel in the rock mass on one side of the trough to connect the pressure relief space and the drainage ditch.

[0006] Preferably, the hollow trough is a cuboid with a depth of 780mm. A bottom plate of a set length is reserved on both sides of the hollow trough. The soil and rock are dug down to a depth of 130mm, and then 50mm of concrete is poured. Studs are pre-embedded in the concrete at intervals. The remaining 80mm is the thickness of the drainage grid.

[0007] Preferably, stud holes are provided on both sides of the drainage grid corresponding to the studs, and nuts are used to connect the studs and fasten the drainage grid.

[0008] Preferably, in step 2), three layers of steel mesh are laid at intervals along the height of the steel pipe, and the bottom end of the steel pipe is locked to the base plate using a tray and nuts.

[0009] Preferably, in step 3), the concrete pouring height is 500mm, and the length of the steel pipe is the same as the concrete height.

[0010] Preferably, the surface of the concrete body poured in step 3) has a slope of 0.3%.

[0011] Preferably, the height of the second pressure relief space is 200mm.

[0012] Preferably, the length of the pressure relief space along the direction of the roadway is consistent with the length of the empty slot.

[0013] Preferably, the diversion channel is higher than the water level of the drainage ditch during normal drainage, and the diversion channel is arranged at an angle.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. For roof water leakage, the water can be discharged into the drainage ditch in a timely manner through the pressure relief space and the water diversion channel to avoid roadway floor heave caused by water accumulation in the floor. 2. Grouting anchors are installed in the bottom slab, steel mesh is laid and welded to the steel pipe, and then concrete is poured. The three-pronged approach greatly enhances the integrity and resistance to deformation of the surrounding rock of the roadway floor, resulting in a significant reinforcement effect on the roadway floor. At the same time, it prevents water from coming into contact with the soft rock floor. 3. Since the bottom slab is soft rock, lateral compression may occur on both sides of the trough, causing bottom bulging. Pressure relief space one is left on both sides, which is a buffer space and plays a role in pressure relief. In the vertical direction, pressure relief space two plays a role in drainage. When the bottom bulging is particularly severe, even the concrete body and baffle are damaged. Pressure relief space two also plays a role in pressure relief. At this time, the sidewalk drainage grid can be removed and the bulging part can be excavated to ensure the basic shape of pressure relief space one and pressure relief space two. 4. The sidewalk drainage grates are fixed with nuts to prevent them from moving. When it is necessary to manage the pressure relief space, they can be opened. At the same time, the condition of the bottom plate bulging can be observed through the drainage grates so that timely treatment can be carried out. Attached Figure Description

[0015] Figure 1 This is a schematic cross-sectional view of the present invention; Figure 2 This is a schematic diagram of the overall layout of the present invention; Figure 3 This is a top view of the drainage grid of the present invention; The diagram is labeled as follows: 1. Empty groove, 101. Pressure relief space one, 102. Pressure relief space two, 2. Concrete body, 3. Baffle, 4. Drainage grid, 401. Stud hole, 5. Drainage channel, 6. Drainage ditch, 7. Steel pipe, 8. Steel mesh, 9. Anchor bolt, 10. Tray, 11. Boss, 12. Stud. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0017] Please see Figure 1-3 A method for preventing floor heave in soft rock slabs includes the following steps: 1) In the water-spraying section of the soft rock base, excavate a hollow trench 1 and spray grout the walls of the hollow trench 1; 2) Install several grouting anchor rods 9 at intervals on the bottom plate of the empty trench 1. A steel pipe 7 is vertically welded to the tail of each anchor rod 9. Multiple layers of steel mesh 8 are laid on the steel pipe 7 at intervals, and the steel mesh 8 is welded to the steel pipe 7. 3) Pour concrete into the empty groove 1 and let it solidify to form a concrete body 2. A predetermined width is reserved between the two sides of the empty groove 1 and the concrete body 2 to form a pressure relief space 101. A baffle 3 is poured above the pressure relief space 101 to connect the concrete body 2 and the side wall of the empty groove 1. 4) Lay a drainage grid 4 on top of the concrete body 2. The drainage grid 4 is flush with the tunnel floor and there is a pressure relief space of 102 between it and the concrete body 2. 5) In the rock mass on one side of the empty trough 1, a diversion channel 5 is opened to connect the pressure relief space 2 102 and the drainage ditch 6.

[0018] In step 1), for the stage of severe water seepage in the soft rock floor, a rectangular trench 1 with a depth of 780mm is excavated in the direction perpendicular to the tunnel. A predetermined length of floor slab is reserved on both sides of the trench 1. Rock and soil are excavated to a depth of 130mm, and then 50mm of concrete is poured to form a boss 11. Studs 12 are pre-embedded at intervals in the boss 11. The remaining 80mm is the thickness of the drainage grid 4. The length of the trench 1 along the tunnel direction is determined according to the size of the water-seeping area on the roof.

[0019] The drainage grid 4 has stud holes 401 on both sides corresponding to the studs 12, and nuts are used to connect the studs 12 to secure the drainage grid 4. The drainage grid 4 is composed of many squares, and the diameter of the square holes is smaller than that of the stud holes 401, which facilitates the nuts to lock the studs 12 and restricts the movement of the sidewalk drainage grid 4. The studs 12 are set along the direction of the alley.

[0020] In step 2), there are 12 anchor rods 9 for grouting the bottom plate, and 12 steel pipes 7 welded to the tail of the anchor rods 9 (the size of the crater and the number of anchor rods can be determined on site according to the rock type of the bottom plate). The steel mesh 8 is three layers, which are laid at intervals along the height of the steel pipes 7 at the top, middle and bottom of the steel pipes 7, and the bottom end of the steel pipes 7 is locked to the bottom plate with a tray 10 and a nut to further reinforce the bottom plate.

[0021] In step 3), the concrete body 2 is poured to a height of 500mm, and the length of the steel pipe 7 is the same as the height of the concrete body 2. The surface of the concrete body 2 has a slope of 0.3% to facilitate drainage. At the same time, the concrete body 2 isolates water and prevents water from contacting the soft rock of the base slab.

[0022] The height of the pressure relief space 2 102 is 200mm, which mainly serves as a buffer and drainage function. When the bottom bulge causes a protrusion, the protruding concrete body 2 will gradually fill the pressure relief space 2 102. At this time, the sidewalk drainage grid 4 can be removed, the protruding part can be excavated, the basic shape of the pressure relief space 2 102 can be maintained, and water can be prevented from accumulating in the pressure relief space 2 102.

[0023] The length of the pressure relief space 101 along the direction of the roadway is consistent with the length of the empty slot 1. In the direction perpendicular to the direction of the roadway, the length of the pressure relief space 101 can be set according to the lithology of the soft rock floor.

[0024] The diversion channel 5 is higher than the water level of the drainage ditch 6 during normal drainage, so as to prevent the water in the drainage ditch 6 from flowing into the pressure relief space 102 through the diversion channel 5. The diversion channel 5 is also inclined to facilitate the drainage of water accumulated in the pressure relief space 102 to the drainage ditch.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made within the spirit and principles of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preventing floor heave in soft rock floor slabs, characterized in that, Includes the following steps: 1) In the water-spraying section of the soft rock base, excavate a hollow trench and spray grout the trench walls; 2) Install several grouting anchors at intervals on the bottom plate of the empty trench. A steel pipe is vertically welded to the end of each anchor. Multiple layers of steel mesh are laid on the steel pipe at intervals, and the steel mesh is welded to the steel pipe. 3) Pour concrete into the empty groove and let it solidify to form a concrete body. Leave a predetermined width between the two sides of the empty groove and the concrete body to form a pressure relief space 1. Pour a baffle above the pressure relief space 1 to connect the concrete body and the side wall of the empty groove. 4) Lay a drainage grid on top of the concrete structure, with the drainage grid flush with the tunnel floor and with a pressure relief space between it and the concrete structure. 5) A diversion channel is drilled in the rock mass on one side of the trough to connect the pressure relief space and the drainage ditch. The water level of the diversion channel is higher than that of the drainage ditch during normal drainage, and the diversion channel is arranged at an angle.

2. The method for preventing floor heave in soft rock floorboards according to claim 1, characterized in that, The trough is rectangular and 780mm deep. A bottom plate of a set length is reserved on both sides of the trough. The soil and rock are dug down to a depth of 130mm, and then 50mm of concrete is poured. Studs are embedded in the concrete at intervals. The remaining 80mm is the thickness of the drainage grid.

3. The method for preventing floor heave in soft rock floor slabs according to claim 2, characterized in that, The drainage grid has stud holes on both sides corresponding to the studs, and nuts are used to connect the studs and fasten the drainage grid.

4. The method for preventing floor heave in soft rock floor slabs according to claim 1, characterized in that, In step 2), three layers of steel mesh are laid at intervals along the height of the steel pipe, and the bottom end of the steel pipe is locked to the base plate with a tray and nuts.

5. A method for preventing floor heave in soft rock floor slabs according to claim 1, characterized in that, In step 3), the concrete pouring height is 500mm, and the length of the steel pipe is the same as the concrete height.

6. A method for preventing floor heave in soft rock as described in claim 1, characterized in that, The concrete surface poured in step 3) has a slope of 0.3%.

7. A method for preventing floor heave in soft rock floor slabs according to claim 1, characterized in that, The height of the pressure relief space 2 is 200mm.

8. A method for preventing floor heave in soft rock floor slabs according to claim 1, characterized in that, The length of the pressure relief space along the direction of the roadway is consistent with the length of the empty slot.

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