Composite stress structure for reinforcing roof of base concealed karst cave and construction method of composite stress structure

Abstract

The invention relates to a composite stress structure for reinforcing a roof of a base concealed karst cave and a construction method of the composite stress structure. A composite stress structure for reinforcing a roof of a base concealed karst cave comprises a reinforced concrete slab, the reinforced concrete slab is located above a roof surrounding rock of the karst cave, the reinforced concrete slab is in rigid connection with the roof surrounding rock, and the two ends of the reinforced concrete slab are anchored and supported on complete bed rocks on the two sides of the karst cave. The roof surrounding rock of the karst cave and the reinforced concrete slab structure on the upper portion are rigidly connected together, the effects of coordinated deformation and common stress are achieved, the bearing capacity of the roof surrounding rock of the original karst cave is fully exerted, and the cost of engineering treatment measures is effectively reduced; according to the method, the form that the beam slab crosses the karst cave is adopted, an original karst cave drainage channel is fully reserved, pier columns do not need to be arranged in the karst cave, the influence of karst water scouring is avoided, and the whole-life-cycle structural safety of a bridge or a tunnel is guaranteed; the original ecological form of the karst cave is reserved, and the environment-friendly and economic requirements of engineering construction are met.

Description

Technical Field

[0001] The invention relates to the technical field of engineering treatment of basement concealed karst caves, in particular to a composite force-bearing structure for reinforcing the top plate of a basement concealed karst cave and a construction method thereof. Background Art

[0002] At present, karst is one of the most prominent difficulties in engineering construction. It is inevitable to encounter hidden caves in the basement when constructing infrastructure in karst areas. When the thickness of the top plate of the hidden cave in the basement is insufficient, engineering measures must be adopted to treat it to avoid karst collapse accidents. There are two main types of existing treatment technologies: (1) When the depth of the cave is not large, the top plate of the hidden cave in the basement is exposed and the cave is filled. Or the piers are placed at the bottom of the cave and a beam bridge is used to cross it; (2) When the depth of the cave is relatively large, a single span is used to cross the cave in the form of a plate or bridge, and the two ends of the support are placed on the intact bedrock. When the depth of the cave is not large, the existing technology adopts a cave filling solution, which is easy to damage the original drainage channel for water-passing caves and affect the structural safety of the tunnel throughout its life cycle; the beam bridge is used to cross the cave and the piers are placed at the bottom of the cave. Although this method retains the original drainage channel, the karst water will scour the piers for a long time, which is not conducive to the durability of the structure. At the same time, both solutions cause great damage to the top plate of the hidden cave at the base, and fail to fully utilize the self-stabilizing capacity of the surrounding rock of the cave top plate, which does not conform to the environmental protection and economic concept of engineering construction. When the depth of the cave is relatively large, the existing technology uses a single span of a plate or bridge to cross the cave, which only considers the stress of the engineering structure. Therefore, the plate or bridge structure used is conservative, resulting in high treatment costs. Summary of the invention

[0003] The purpose of the present invention is to provide a composite force-bearing structure for reinforcing the top plate of hidden caves in the basement and a construction method thereof, in view of the problems that the treatment technology adopted in the prior art when the top plate of hidden caves in the basement is insufficient in thickness causes great damage to the top plate of hidden caves in the basement and the plate or bridge structure adopted is expensive.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A composite force-bearing structure for reinforcing the top plate of a hidden karst cave at the base comprises a reinforced concrete plate, wherein the reinforced concrete plate is located above the top plate surrounding rock of the karst cave, the reinforced concrete plate is rigidly connected to the top plate surrounding rock, and both ends of the reinforced concrete plate are anchored and supported on the complete bedrock on both sides of the karst cave.

[0006] The composite load-bearing structure of the top plate reinforced by the base hidden karst cave described in the present invention has a reinforced concrete plate spanning over the top plate surrounding rock of the karst cave. By rigidly connecting the reinforced concrete plate and the top plate surrounding rock, the reinforced concrete plate and the top plate surrounding rock are deformed and stressed together, and the bearing capacity of the top plate surrounding rock of the original karst cave is fully exerted, so that the original load is shared by the reinforced concrete plate and the top plate surrounding rock of the karst cave, and the stress on the reinforced concrete plate is reduced, so that the thickness of the reinforced concrete plate can be reduced, thereby effectively reducing the project cost; and the top plate surrounding rock of the original karst cave is not exposed and damaged, and an upward pulling force is applied to the top plate surrounding rock of the original karst cave through the reinforced concrete plate, so that the load of the top plate surrounding rock of the original karst cave can be transmitted to the intact bedrock at both ends of the reinforced concrete plate and located on both sides of the karst cave through the reinforced concrete plate, so that the top plate surrounding rock structure of the karst cave is more stable, the damage to the top plate surrounding rock of the karst cave is small, and it is strengthened, the original ecological form of the karst cave is retained, and the environmental protection and economic requirements of engineering construction are met. In addition, beams and slabs are used to cross the caves, fully preserving the original cave drainage channels and protecting the newly built structures from the impact of karst water erosion, thus ensuring the structural safety of bridges and tunnels throughout their life cycle.

[0007] Preferably, the reinforced concrete slab is connected to the top plate surrounding rock through a plurality of anchoring structures, and the anchoring structures include a suspension anchor, a casing and a vertical anchor borehole corresponding to the suspension anchor, the casing vertically penetrates the reinforced concrete slab, the anchor borehole is located in the top plate surrounding rock, the suspension anchor is penetrated through the casing and the corresponding anchor borehole, and the casing and the anchor borehole are filled with cement.

[0008] The use of a suspension anchor rod combined with an anchor structure filled with cement makes the rigid connection between the reinforced concrete slab and the surrounding rock of the roof plate better, so that the coordinated deformation and joint force effect of the two are better. In addition, the method of drilling holes in the surrounding rock of the roof plate by anchor rods needs to minimize the damage to the surrounding rock of the roof plate; the method of setting casings on the reinforced concrete slab can be realized by pre-embedded method, which makes the construction simpler.

[0009] Preferably, the anchor borehole passes through the roof surrounding rock, and an anchor iron plate is provided at the bottom of the suspension anchor, and the anchor iron plate can be adapted to enter the anchor borehole.

[0010] The anchor rod hole penetrates the roof surrounding rock, so that the anchoring depth of the suspension anchor rod and the roof surrounding rock is deeper, so that the coordinated deformation and joint force effect of the reinforced concrete slab and the roof surrounding rock are better. An anchor rod iron plate is provided at the bottom of the suspension anchor rod, which can hold the cement in the anchor rod hole, ensure that the cement can fill the anchor rod hole, and ensure the anchoring effect of the suspension anchor rod and the roof surrounding rock.

[0011] Preferably, the cement in the anchor rod borehole is cement roll, and the cement in the casing is cement mortar.

[0012] Preferably, the top of the suspension anchor rod has an anchor head, and the anchor head is located above the top surface of the reinforced concrete slab, so that the rigid connection between the reinforced concrete slab and the surrounding rock of the top slab is better.

[0013] Preferably, the suspension anchor rod has prestress, so that the coordinated deformation and joint force effect of the reinforced concrete slab and the top slab surrounding rock are better.

[0014] Preferably, a plurality of anchor barbs are provided at intervals in the length direction of the suspension anchor, and the anchor barbs are upward and arranged at an acute angle to the suspension anchor, thereby increasing the pull-out resistance of the suspension anchor.

[0015] Preferably, when the reinforced concrete slab is a reinforced concrete arch slab, the reinforced concrete arch slab is anchored to the corresponding complete bedrock through an arch slab base;

[0016] When the reinforced concrete slab is a reinforced concrete flat plate, both ends of the reinforced concrete flat plate are respectively anchored to the corresponding complete bedrock through a plurality of flat plate support anchoring steel bars.

[0017] When the reinforced concrete slab is a reinforced concrete arch slab, the force can be better transferred to the complete bedrock through the arch slab base; when the reinforced concrete slab is a reinforced concrete flat slab, the two ends of the reinforced concrete flat slab are anchored to the complete bedrock by anchoring steel bars at the slab fulcrums, so that the reinforced concrete flat slab can be better supported by the complete bedrock.

[0018] A construction method for a composite force-bearing structure for reinforcing the top plate of a basement hidden karst cave, used for constructing the composite force-bearing structure for reinforcing the top plate of a basement hidden karst cave, comprises the following construction steps:

[0019] S1. Determine the distribution range of the caves, the thickness of the cave roof surrounding rock and the integrity of the roof surrounding rock, and determine the area where the roof surrounding rock needs to be reinforced;

[0020] S2. Drill several anchor holes at vertical intervals in the area where the roof surrounding rock needs to be reinforced;

[0021] S3, insert the suspension anchor into the anchor hole, and then fill the anchor hole with cement;

[0022] S4, tying the steel bars of the reinforced concrete slab so that the two ends of the reinforced concrete slab are anchored and supported on the complete bedrock on both sides of the cave, and the upper end of the suspension anchor rod passes through the steel bar gap of the reinforced concrete slab and is sleeved with a casing;

[0023] S5, pouring reinforced concrete slab;

[0024] S6. After the concrete strength of the reinforced concrete slab reaches the design requirements, prestress is applied to the suspension anchor rod, and then cement mortar is injected into the casing, and then the anchor is sealed through the anchor head.

[0025] The construction method of the composite force-bearing structure for reinforcing the top plate of a hidden karst cave in the basement described in the present invention can quickly and orderly complete the construction of the composite force-bearing structure for reinforcing the top plate of a hidden karst cave in the basement, ensure that the suspension anchor rods can rigidly connect the newly built upper reinforced concrete slab and the top plate surrounding rock of the original karst cave in the lower part with high quality, and can apply prestress to the suspension anchor rods, so that the newly built reinforced concrete slab and the original top plate surrounding rock can coordinate deformation and bear stress together.

[0026] Preferably, in step S1, geophysical exploration is used to preliminarily determine the distribution range of the caves and the thickness of the roof surrounding rock of the caves; then drilling is used to verify the distribution range of the caves, the thickness of the roof surrounding rock of the caves and the integrity of the roof surrounding rock;

[0027] In step S2, the hole produced by drilling is used as a part of the anchor hole or used to process a part of the anchor hole;

[0028] and / or,

[0029] In step S2, the anchor is drilled through the bottom of the roof surrounding rock;

[0030] In step S3, the suspension anchor is inserted into the anchor borehole so that the anchor iron plate at the bottom end of the suspension anchor reaches the bottom end of the anchor borehole, and then the anchor borehole is filled with cement;

[0031] and / or,

[0032] In step S3, a plurality of anchor barbs are arranged at intervals in the length direction of the suspension anchor, and the anchor barbs are arranged upward and at an acute angle to the suspension anchor;

[0033] and / or,

[0034] In step S3, a cement roll is inserted from the upper end of the anchor borehole downward to fill the anchor borehole.

[0035] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0036] 1. The composite force-bearing structure reinforced with the top plate of the hidden karst cave in the base of the present invention adopts the form of beam-slab spanning the karst cave, the top plate surrounding rock of the original karst cave is not exposed and damaged, the original karst cave drainage channel is fully retained and the newly built structure is not affected by karst water scouring, and the structural safety of the bridge and tunnel throughout the life cycle is guaranteed; the reinforced concrete slab spans the top plate surrounding rock of the karst cave, and by rigidly connecting the reinforced concrete slab with the top plate surrounding rock, the reinforced concrete slab and the top plate surrounding rock are coordinated in deformation and jointly stressed, which fully exerts the bearing capacity of the top plate surrounding rock of the original karst cave, so that the original load sharing The reinforced concrete slab and the roof surrounding rock of the cave share the load, and the stress on the reinforced concrete slab is reduced, so that the thickness of the reinforced concrete slab can be reduced, thereby effectively reducing the project cost; the reinforced concrete slab applies an upward pulling force to the roof surrounding rock of the original cave, so that the load of the roof surrounding rock of the original cave can be transmitted through the reinforced concrete slab to the complete bedrock at both ends of the reinforced concrete slab and on both sides of the cave, making the roof surrounding rock structure of the cave more stable, with little damage to the roof surrounding rock of the cave and strengthened, retaining the original ecological form of the cave, and meeting the environmental protection and economic requirements of engineering construction.

[0037] 2. The construction method of the composite force-bearing structure for reinforcing the top plate of a hidden karst cave in the basement according to the present invention can quickly and orderly complete the construction of the composite force-bearing structure for reinforcing the top plate of a hidden karst cave in the basement, and ensure that the suspension anchor rods can rigidly connect the newly built reinforced concrete slab on the upper part and the top plate surrounding rock of the original karst cave at the lower part with high quality, and can apply prestress to the suspension anchor rods, so that the newly built reinforced concrete slab and the original top plate surrounding rock can coordinate deformation and bear stress together. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of a composite force-bearing structure (reinforced concrete arch plate) for reinforcing the top plate of a base hidden karst cave of the present invention;

[0039] Figure 2 It is a schematic diagram of the connection state of the composite force-bearing structure reinforced with the top plate of the base hidden cave of the present invention (reinforced concrete arch plate);

[0040] Figure 3 It is a structural diagram of the suspension anchor;

[0041] Figure 4 It is a structural schematic diagram of a composite force-bearing structure (reinforced concrete flat plate) for reinforcing the top plate of a base concealed karst cave according to the present invention;

[0042] Figure 5 It is a schematic diagram of the connection state of the composite force-bearing structure for reinforcing the top plate of the base hidden karst cave of the present invention (reinforced concrete flat plate).

[0043] Icons: 11. Reinforced concrete arch slab; 12. Reinforced concrete flat slab; 2. Top slab surrounding rock; 3. Suspension anchor rod; 301. Anchor rod iron plate; 302. Anchor rod barb; 41. Arch slab base; 42. Flat slab fulcrum anchor steel bar; 5. Anchor rod drilling hole; 6. Cement medicine roll; 7. Casing; 8. Cement mortar; 9. Sealing anchor head; 10. Cave; 101. Complete bedrock. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] Example 1

[0047] This embodiment provides a composite force-bearing structure for reinforcing the top plate of a basement hidden cave, see Figure 1-Figure 5 , including a reinforced concrete slab, which is located above the roof surrounding rock 2 of the cave 10, and is rigidly connected to the roof surrounding rock 2. Both ends of the reinforced concrete slab are anchored and supported on the complete bedrock 101 on both sides of the cave 10.

[0048] In this solution, the reinforced concrete slab can be used as a bridge main beam or a tunnel base for traffic operations across the cave 10.

[0049] like Figure 1 and Figure 2 As shown, when the span of the cave 10 is large, the reinforced concrete slab is a reinforced concrete arch slab 11, which spans the top of the cave 10, and the top plate surrounding rock 2 above the cave 10 is not exposed and damaged. The reinforced concrete arch slab 11 is located above the top plate surrounding rock 2 of the cave 10 and is rigidly connected to the top plate surrounding rock 2, so that the two can coordinate deformation and bear force together. Because the bearing capacity of the top plate surrounding rock 2 of the original cave 10 is fully utilized, the original load is shared by the reinforced concrete slab and the top plate surrounding rock 2 of the cave 10, the stress of the reinforced concrete slab is reduced, so that the thickness of the reinforced concrete arch slab 11 can be reduced, thereby effectively reducing the project cost.

[0050] In addition, an arch base 41 is provided at the arch feet at both ends of the reinforced concrete arch slab 11, and the arch base 41 is anchored together with the complete bedrock 101 on both sides of the cave 10, so that the arch base 41 can well bear the weight of the reinforced concrete arch slab 11 itself and the force during operation. In addition, the reinforced concrete arch slab 11 is rigidly connected to the top plate surrounding rock 2, and the reinforced concrete arch slab 11 can pull the top plate surrounding rock 2 upward, so that the load of the top plate surrounding rock 2 can be dispersed to the arch base 41 through the reinforced concrete arch slab 11, and then borne by the complete bedrock 101, making the structure of the top plate surrounding rock 2 safer.

[0051] In this embodiment, a beam-slab form is adopted to cross the karst cave 10, the top plate surrounding rock 2 of the original karst cave 10 is not exposed or damaged, the drainage channel of the original karst cave 10 is fully retained and the newly built structure is not affected by karst water erosion, so that the structural safety of the bridge and tunnel throughout the life cycle is guaranteed.

[0052] In this embodiment, the reinforced concrete slab and the top plate surrounding rock 2 are rigidly connected by the existing technology. Figure 3 As shown, the reinforced concrete slab is connected to the top plate surrounding rock 2 through a number of anchoring structures, and the anchoring structures include a suspension anchor 3, a casing 7 and a vertical anchor bore 5 corresponding to the suspension anchor 3, the casing 7 vertically penetrates the reinforced concrete slab, the anchor bore 5 is located in the top plate surrounding rock 2, the suspension anchor 3 is penetrated by the casing 7 and the corresponding anchor bore 5, and the casing 7 and the anchor bore 5 are filled with cement.

[0053] In this embodiment, the anchor structure of the suspension anchor rod 3 and the cement filling is used to achieve a good rigid connection effect between the reinforced concrete slab and the top plate surrounding rock 2, so that the coordinated deformation and joint force effect of the two are better. In addition, the top plate surrounding rock 2 adopts the anchor rod drilling 5 method, and the damage to the top plate surrounding rock 2 needs to be reduced as much as possible; the reinforced concrete slab adopts the casing 7 method, which can be implemented by pre-embedding, and the construction is simpler. The casing 7 can be a PVC pipe, etc.

[0054] In this embodiment, it is appropriate to penetrate the anchor hole 5 through the roof surrounding rock 2, so that the anchoring depth of the suspension anchor 3 and the roof surrounding rock 2 is deeper, so that the coordinated deformation and joint force effect of the reinforced concrete slab and the roof surrounding rock 2 are better. An anchor iron plate 301 is provided at the bottom of the suspension anchor 3, which can hold the cement in the anchor hole 5, ensure that the cement can fill the anchor hole 5, and ensure the anchoring effect of the suspension anchor 3 and the roof surrounding rock 2.

[0055] In this embodiment, the cement in the anchor borehole 5 is cement roll 6 , and the cement in the casing 7 is cement mortar 8 .

[0056] In this embodiment, the top of the suspension anchor rod 3 has an anchor head 9, and the anchor head 9 is located above the top surface of the reinforced concrete slab, so that the rigid connection effect between the reinforced concrete slab and the top plate surrounding rock 2 is better.

[0057] In this embodiment, the suspension anchor rod 3 also has prestress, so that the coordinated deformation and joint force effect of the reinforced concrete slab and the top plate surrounding rock 2 are better.

[0058] In this embodiment, a plurality of anchor barbs 302 are provided at intervals in the length direction of the suspension anchor 3 . The anchor barbs 302 are upward and are arranged at an acute angle to the suspension anchor 3 , thereby increasing the pull-out resistance of the suspension anchor 3 .

[0059] Example 2

[0060] This embodiment provides a composite force-bearing structure for reinforcing the top plate of a base hidden cave, which is different from the embodiment 1 in that: Figure 4 and Figure 5 As shown, both ends of the reinforced concrete slab 12 are anchored to the corresponding complete bedrock 101 through a number of slab support anchoring steel bars 42. It is applied to the case where the cross-span of the cave is relatively small. The two ends of the reinforced concrete slab 12 are anchored to the complete bedrock 101 through the slab support anchoring steel bars 42, so that the reinforced concrete slab 12 can be better supported by the complete bedrock 101.

[0061] In this embodiment, the plate support anchoring steel bars 42 may be coiled anchor rods or the like to ensure the anchoring strength between the reinforced concrete plate 12 and the intact bedrock 101 .

[0062] Example 3

[0063] This embodiment provides a construction method for a composite force-bearing structure for reinforcing the top plate of a basement hidden karst cave, which is used to construct the composite force-bearing structure for reinforcing the top plate of a basement hidden karst cave as described in Embodiment 1 or Embodiment 2, and includes the following construction steps:

[0064] S1, determine the distribution range of the karst cave 10, the thickness of the roof surrounding rock 2 of the karst cave 10, and the integrity of the roof surrounding rock 2, and determine the area where the roof surrounding rock 2 needs to be reinforced; in step S1, a geophysical prospecting method can be used to preliminarily determine the distribution range of the karst cave 10 and the thickness of the roof surrounding rock 2 of the karst cave 10; then a drilling method is used to verify the distribution range of the karst cave 10, the thickness of the roof surrounding rock 2 of the karst cave 10, and the integrity of the roof surrounding rock 2, so that the distribution range of the karst cave 10, the thickness of the roof surrounding rock 2 of the karst cave 10, and the integrity of the roof surrounding rock 2 can be obtained more accurately, which is convenient for determining the area where the roof surrounding rock 2 needs to be reinforced, and then it is convenient to determine the location, number and size of the anchor borehole 5;

[0065] S2, drilling a number of anchor holes 5 at intervals in the area where the roof surrounding rock 2 needs to be reinforced; in step S2, the holes produced by drilling can be used as part of the anchor holes 5 or used to process part of the anchor holes 5, and the holes produced by drilling can be reused, which can reduce the damage to the roof surrounding rock 2 and help reduce the drilling time of the anchor holes 5. The anchor holes 5 are suitable for passing through the bottom of the roof surrounding rock 2, so that the anchoring depth of the suspension anchor 3 in the roof surrounding rock 2 is greater;

[0066] S3, insert the suspension anchor rod 3 into the anchor rod drilling hole 5, and then fill the anchor rod drilling hole 5 with cement; the bottom end of the suspension anchor rod 3 can be inserted to the bottom end of the anchor rod drilling hole 5, and then the anchor rod drilling hole 5 can be filled by pouring cement from top to bottom; or the anchor rod drilling hole 5 can be filled by inserting the cement medicine roll 6 from top to bottom; when the anchor rod drilling hole 5 is deeper, the suspension anchor rod 3 can be inserted downward to a certain depth, and then the cement medicine roll 6 can be inserted to fill the anchor rod drilling hole 5, so as to cyclically deepen the insertion depth of the suspension anchor rod 3 in the anchor rod drilling hole 5 and increase the cement medicine roll The amount of roll 6 inserted can better ensure that the cement roll 6 can fill the anchor borehole 5; when the anchor borehole 5 passes through the bottom of the top plate surrounding rock 2, the suspension anchor 3 is inserted into the anchor borehole 5, and the anchor iron plate 301 at the bottom of the suspension anchor 3 needs to reach the bottom of the anchor borehole 5, and then the anchor borehole 5 is filled with cement; and in step S3, a plurality of anchor barbs 302 are provided at intervals in the length direction of the suspension anchor 3, and the anchor barbs 302 are upward and arranged at an acute angle to the suspension anchor 3;

[0067] S4, tie up the steel bars of the reinforced concrete slab so that the two ends of the reinforced concrete slab are respectively anchored and supported on the complete bedrock 101 on both sides of the cave 10, and the upper end of the suspension anchor rod 3 passes through the steel bar gap of the reinforced concrete slab and is sleeved with a sleeve 7, and the sleeve 7 is connected to the steel bars of the reinforced concrete slab; when the reinforced concrete slab is a reinforced concrete arch slab 11, tie up and fix the steel cage of the reinforced concrete arch slab 11, and detect the complete bedrock 101 anchored by the arch slab base 41 at both ends of the reinforced concrete arch slab 11 to ensure that the arch slab base 41 at both ends is placed on the complete bedrock 101; when the reinforced concrete slab is a reinforced concrete flat plate 12, tie up and fix the steel cage of the reinforced concrete flat plate 12, and detect the surrounding rocks of the fulcrums at both ends of the reinforced concrete flat plate 12 to ensure that the fulcrums at both ends of the reinforced concrete flat plate 12 are placed on the complete bedrock 101, and the two ends of the fulcrums use drug-coiled anchor rods as flat plate fulcrums to anchor the steel bars 42 and the complete bedrock 101 together.

[0068] S5, pouring reinforced concrete slab;

[0069] S6. After the concrete strength of the reinforced concrete slab reaches the design requirement, prestress is applied to the suspension anchor rod 3, and then cement mortar 8 is injected into the sleeve 7, and then the anchor is sealed through the anchor head 9.

[0070] The construction method of the composite load-bearing structure for reinforcing the roof of a hidden karst cave in the base described in this embodiment can quickly and orderly complete the construction of the composite load-bearing structure for reinforcing the roof of a hidden karst cave in the base in Example 1 or Example 2, ensuring that the suspension anchor 3 can rigidly connect the newly built upper reinforced concrete slab and the roof surrounding rock 2 of the original cave 10 at the bottom with high quality, and can apply prestress to the suspension anchor 3, so that the newly built reinforced concrete slab and the original roof surrounding rock 2 can coordinate deformation and bear stress together.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite force-bearing structure for reinforcing the top plate of a basement hidden cave, characterized in that: It comprises a reinforced concrete slab, which is located above the roof surrounding rock (2) of a karst cave (10), the reinforced concrete slab is rigidly connected to the roof surrounding rock (2), and both ends of the reinforced concrete slab are anchored and supported on the complete bedrock (101) on both sides of the karst cave (10).

2. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 1 is characterized in that: The reinforced concrete slab is connected to the top plate surrounding rock (2) via a plurality of anchoring structures, wherein the anchoring structures include a suspension anchor (3), a casing (7) and a vertical anchor borehole (5) corresponding to the suspension anchor (3); the casing (7) vertically penetrates the reinforced concrete slab; the anchor borehole (5) is located in the top plate surrounding rock (2); the suspension anchor (3) is passed through the casing (7) and the corresponding anchor borehole (5); and the casing (7) and the anchor borehole (5) are filled with cement.

3. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 2 is characterized in that: The anchor rod drilling hole (5) passes through the roof surrounding rock (2), and an anchor rod iron plate (301) is provided at the bottom of the suspension anchor rod (3), and the anchor rod iron plate (301) can be adapted to enter the anchor rod drilling hole (5).

4. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 3 is characterized in that: The cement in the anchor rod borehole (5) is cement roll (6), and the cement in the casing (7) is cement mortar (8).

5. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 2 is characterized in that: The top of the suspension anchor rod (3) is provided with an anchor head (9), and the anchor head (9) is located above the top surface of the reinforced concrete slab.

6. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 5, characterized in that: The suspension anchor rod (3) has prestress.

7. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to claim 2 is characterized in that: A plurality of anchor barbs (302) are arranged at intervals in the length direction of the suspension anchor (3), and the anchor barbs (302) are arranged upward and at an acute angle to the suspension anchor (3).

8. The composite force-bearing structure for reinforcing the top plate of a basement hidden cave according to any one of claims 1 to 7, characterized in that: When the reinforced concrete slab is a reinforced concrete arch slab (11), the reinforced concrete arch slab (11) is anchored to the corresponding complete bedrock (101) through an arch slab base (41); When the reinforced concrete slab is a reinforced concrete flat plate (12), both ends of the reinforced concrete flat plate (12) are respectively anchored to the corresponding complete bedrock (101) via a plurality of flat plate support anchoring steel bars (42).

9. A construction method for a composite force-bearing structure for reinforcing the top plate of a basement hidden karst cave, characterized in that: The composite force-bearing structure for reinforcing the top plate of a basement hidden cave as claimed in any one of claims 1 to 8 comprises the following construction steps: S1, judging the distribution range of the karst cave (10), the thickness of the roof surrounding rock (2) of the karst cave (10), and the integrity of the roof surrounding rock (2), and determining the area of ​​the roof surrounding rock (2) that needs to be reinforced; S2, drilling a plurality of anchor holes (5) at intervals vertically in the area of ​​the top plate surrounding rock (2) that needs to be reinforced; S3, inserting the suspension anchor (3) into the anchor borehole (5), and then filling the anchor borehole (5) with cement; S4, tying the steel bars of the reinforced concrete slab so that the two ends of the reinforced concrete slab are anchored and supported on the complete bedrock (101) on both sides of the cave (10), and the upper end of the suspension anchor rod (3) passes through the gap between the steel bars of the reinforced concrete slab and is sleeved with a casing (7); S5, pouring reinforced concrete slab; S6. After the concrete strength of the reinforced concrete slab reaches the design requirement, prestress is applied to the suspension anchor rod (3), and then cement mortar (8) is injected into the sleeve (7), and then the anchor is sealed through the anchor head (9).

10. The construction method of the composite force-bearing structure for reinforcing the top plate of the basement hidden karst cave according to claim 9, characterized in that: In step S1, geophysical exploration is used to preliminarily determine the distribution range of the karst cave (10) and the thickness of the roof surrounding rock (2) of the karst cave (10); then drilling is used to verify the distribution range of the karst cave (10), the thickness of the roof surrounding rock (2) of the karst cave (10), and the integrity of the roof surrounding rock (2); In step S2, the hole produced by drilling is used as a partial anchor borehole (5) or used for processing a partial anchor borehole (5); and / or, In step S2, the anchor drill hole (5) passes through the bottom of the roof surrounding rock (2); In step S3, the suspension anchor (3) is inserted into the anchor bore hole (5) so that the anchor iron plate (301) at the bottom end of the suspension anchor (3) reaches the bottom end of the anchor bore hole (5), and then the anchor bore hole (5) is filled with cement; and / or, In step S3, a plurality of anchor barbs (302) are arranged at intervals in the length direction of the suspension anchor (3), and the anchor barbs (302) are arranged upward and at an acute angle to the suspension anchor (3); and / or, In step S3, a cement roll (6) is inserted from the upper end of the anchor borehole (5) downward to fill the anchor borehole (5).

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