A slope concealed cave filling structure and method

Abstract

The present application relates to the technical field of slope construction, and discloses a kind of concealed karst cave filling structure and method of slope, wherein, structure includes: first prestressed anchoring component being arranged in the rock-soil body of cave bottom, multiple filling bodies being filled in layers from bottom to top, and multiple second prestressed anchoring components corresponding to the number of filling bodies, and each group of second prestressed anchoring components penetrates a layer of filling body and is anchored into the rock-soil body on both sides of cave.The method of the present application first arranges bottom anchoring, then fills in layers and applies prestressed anchor rod layer by layer.The present application can in-situ reinforce cave without excavating slope, and forms stable whole by layer anchoring, which is safe and efficient in construction.

Description

Technical Field

[0001] This invention relates to the field of slope engineering construction technology, specifically to a filling structure and filling method for hidden karst caves in slopes. Background Technology

[0002] In the construction of highways, railways, water conservancy, municipal engineering, and building projects, slope excavation and support often encounter karst geological conditions. In karst-developed areas, hidden karst caves may exist inside the slope, meaning that although these caves are not directly exposed on the slope surface, their cavity structure already poses a potential impact on the overall stability of the slope. If these karst caves are not identified and properly addressed before or during construction, they may lead to local slope instability and landslides, and in severe cases, may even affect the overall safety and subsequent usability of the project.

[0003] Currently, the treatment of concealed karst caves in engineering projects typically follows the approach of "exposing first, then filling, and finally repairing." That is, after a concealed karst cave is discovered inside a slope through geological survey reports, advanced drilling, or on-site exploration, it is often necessary to continue excavating the slope surface to directly expose the cave to the outside world, then fill the cave, and finally rebuild the slope structure and its protection system. This method is quite common in engineering practice. Its principle lies in directly exposing the location of the karst cave, allowing construction personnel to visually determine its extent and carry out filling operations.

[0004] However, existing methods involve repeated construction. To fill the karst cave and ensure safety, it is necessary to continue excavating the slope to fill it, resulting in long construction times and high consumption of mechanical resources. At the same time, during the excavation process, the closer the excavation face is to the karst cave, the greater the disturbance to the karst cave and the more unstable its stress. If proper support work is not done, it is very easy to cause the slope to collapse and landslide.

[0005] Therefore, how to effectively fill and reinforce hidden karst caves without large-scale excavation and with minimal disturbance to the original slope structure is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a structure and method for filling hidden karst caves on slopes, so as to solve the technical problems in the prior art that require large-scale excavation of slopes to fill hidden karst caves, resulting in repeated construction, high resource consumption, and high construction safety hazards.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A slope concealed karst cave filling structure includes: a first prestressed anchoring component disposed in the rock and soil mass at the bottom of the karst cave; multiple layers of filling material, each of the filling materials filling the cavity of the karst cave in layers from bottom to top; a plurality of second prestressed anchoring components, the number of the second prestressed anchoring components corresponding to the number of the filling materials; and one of the second prestressed anchoring components penetrating one layer of the filling material and anchored into the rock and soil mass on opposite sides of the karst cave.

[0008] According to the above-mentioned technical means, the present invention provides a bottom bearing foundation before the filling construction begins by setting a first prestressed anchoring component in the rock and soil mass at the bottom of the karst cave. When the subsequent layered filling is constructed layer by layer, the self-weight of each layer of filling and the construction load are transferred to the bottom through the filling and borne by the first prestressed anchoring component, thus avoiding shear failure or overall sinking of the filling material under its own weight.

[0009] Simultaneously, this invention incorporates a second prestressed anchoring assembly corresponding to the number of infill layers. Each set of second prestressed anchoring assemblies penetrates a corresponding layer of infill and anchors into the soil and rock on opposite sides of the karst cave, forming a beaded anchoring structure. This ensures that each layer of infill, after solidification, is no longer an isolated block but rather forms an integrated load-bearing system with the stable soil and rock on both sides of the karst cave through multiple penetrating second prestressed anchor rods. Since there is no need to excavate the slope surface to expose the karst cave, the original stress balance state and soil structure of the slope are preserved to the greatest extent, avoiding collapse accidents caused by soil instability at the top of the karst cave during excavation.

[0010] Furthermore, the layered filling and layered anchoring design allows each layer of filling to bear load independently. Even if a local defect occurs in a certain layer of filling during construction, it will not affect the load-bearing capacity of other layers, and the redundancy and safety of the overall structure are significantly improved.

[0011] Furthermore, the first prestressed anchoring assembly includes a first prestressed anchor rod.

[0012] Based on the aforementioned technical means, the first prestressed anchoring component is specifically defined as the first prestressed anchor rod. Prestressed anchor rods have advantages such as high load-bearing capacity, convenient construction, and adjustable anchoring depth. Using the first prestressed anchor rod as the bottom load-bearing component allows for precise control of the magnitude and direction of the anchoring force, ensuring that the bottom anchoring system can effectively resist the downward load generated by the weight of the filling material during subsequent layered filling processes.

[0013] Furthermore, there are multiple first prestressed anchor rods, which are arranged at intervals along the horizontal direction.

[0014] Based on the above technical means, the first prestressed anchor rods are set as multiple rods and arranged at intervals along the horizontal direction, forming a bottom group anchor structure. The soil and rock between adjacent first prestressed anchor rods are effectively compacted, which can provide uniform bearing reaction force throughout the entire range at the bottom of the karst cave.

[0015] Furthermore, each of the second prestressed anchoring components includes a second prestressed anchor rod.

[0016] Based on the above technical means, the second prestressed anchoring component is specifically defined as the second prestressed anchor rod. The second prestressed anchor rod can penetrate the filling layer and extend into the rock and soil on the opposite side of the karst cave, so that each layer of filling can be prestressed by tensioning the anchor rod after solidification, thereby actively squeezing the filling and making it in close contact with the karst cave wall, eliminating the gap between the filling and the surrounding rock, and improving stability.

[0017] Furthermore, there are multiple second prestressed anchor rods, which are arranged at intervals along the horizontal direction; each second prestressed anchor rod penetrates the filling body of the corresponding layer and is anchored into the rock and soil on opposite sides of the karst cave.

[0018] Based on the aforementioned technical methods, multiple second prestressed anchor rods are arranged at horizontal intervals in each layer of infill material, forming an interlayer group anchor structure. This ensures that each layer of infill material is uniformly constrained by multiple anchor points in the horizontal plane, preventing uneven deformation or local detachment of the infill material. More importantly, each second prestressed anchor rod penetrates the corresponding layer of infill material and anchors into the rock and soil on opposite sides of the karst cave. This allows for layer-by-layer anchoring during construction, forming an independent stable system after each layer is completed before proceeding to the next layer. This timely locking of the stability of each layer of infill material significantly reduces the risk of infill material collapse during construction.

[0019] Furthermore, each of the fillers is a cementitious material.

[0020] Based on the aforementioned technical methods, the cementitious material possesses self-hardening and self-bearing capabilities. During the solidification process, it can form a good bond with the anchor bolts and surrounding rock, creating a composite structure with good integrity. The cementitious material also exhibits good fluidity, allowing it to be injected into the cavities of the karst cave through grouting holes, filling them densely and minimizing the risk of leaving voids.

[0021] Furthermore, each of the aforementioned fillers is fine concrete.

[0022] Based on the aforementioned technical methods, fine concrete possesses the characteristics of small aggregate particle size, good fluidity, and high strength. Compared to ordinary concrete, fine concrete is easier to inject into narrow spaces, filling all irregular voids within karst caves and adhering more tightly to the cave walls. Fine concrete exhibits high compressive strength after curing, enabling it to withstand significant overburden pressure and slope thrust. Furthermore, the bond strength between fine concrete and prestressed anchors is also high, effectively transferring prestress.

[0023] Furthermore, each of the aforementioned fillers is cement grout.

[0024] Based on the aforementioned technical methods, cement grout possesses excellent fluidity and permeability, enabling it to fill minute fissures and pores within karst caves. It can even penetrate the pores of the surrounding rock and soil, thus reinforcing the surrounding rock. After solidification, the cement grout exhibits even better adhesion to the surrounding rock, making it particularly suitable for karst caves with fractured or fissured surrounding rock.

[0025] A method for filling concealed karst caves on slopes, used to achieve the above-mentioned structure, includes the following steps: S1. Arrange the first prestressed anchoring component in the rock and soil mass at the bottom of the karst cave; S2. Divide the cavity of the cave into multiple filling layers; S3. Use the filler and the second prestressed anchoring assembly to fill the cavity of the karst cave from bottom to top.

[0026] Based on the aforementioned technical means, the method provided by this invention, with the core concept of "first bottom anchoring, then layer division, and finally layer-by-layer filling and anchoring," completely changes the traditional mode of "first excavation and exposure, then filling, and finally repair" in existing technologies. First, a first prestressed anchoring component is placed in the soil and rock mass at the bottom of the karst cave. This step is completed before the filling construction, providing a pre-set bottom bearing foundation for all subsequent filling layers. Second, the karst cave cavity is divided into multiple filling layers, which is a prerequisite for layered construction. The number and height of the layers can be determined based on the actual size of the karst cave and slope stability calculations, offering great flexibility. Finally, the filling material and the second prestressed anchoring component are used to fill each layer from bottom to top, ensuring that each layer can independently bear loads after construction, and that the construction of the next layer will not disturb the already solidified lower layer. Because this method does not require excavation of the slope surface throughout the entire process, the overlying soil of the karst cave remains in its original state, avoiding the risk of instability induced by excavation.

[0027] Furthermore, step S3 specifically includes: S31. Drill holes in the current filling layer so that the holes penetrate the karst cave and extend into the rock and soil on the opposite side of the karst cave, forming a beaded anchor bolt hole. S32. Insert the second prestressed anchor into the borehole and reserve a grouting hole in the current filling layer; S33. Inject the filler through the grouting hole, and stop grouting after the grouting volume reaches the designed height; S34. After the filler in the current filling layer reaches the design strength, prestress is applied to the second prestressed anchor rod. S35. Repeat S31 to S34 until all infill layers are completed.

[0028] According to the above-mentioned technical means, in step S31, the borehole penetrates the karst cave and extends to the opposite rock and soil mass, forming a "beaded" anchor bolt hole. That is, a second prestressed anchor bolt passes sequentially through the slope side rock and soil mass, the current filling layer space, and the opposite rock and soil mass, so that the second prestressed anchor bolt connects the stable strata on both sides of the karst cave with the filling material, forming an integral force chain. In step S32, the second prestressed anchor bolt is first inserted and a grouting hole is reserved. The function of the grouting hole is to inject grout into the borehole before or simultaneously with the filling material injection, ensuring that a strong bond is formed between the second prestressed anchor bolt and the surrounding rock and the filling material. In step S34, prestress is applied after the filling material reaches the design strength, ensuring that the prestress can be effectively transferred without damaging the uncured filling material. After the prestress is applied, the filling material is under triaxial compression, and its crack resistance and bearing capacity are greatly improved. In step S35, the above steps are repeated until all filling layers are completed, forming a multi-layer "filler-second prestressed anchor" composite structure. Each layer is an independent stable unit, while being connected as a whole through a common bottom anchoring component.

[0029] The beneficial effects achieved by this invention are as follows: This invention provides a bottom bearing foundation before the filling construction begins by installing a first prestressed anchoring component in the rock and soil mass at the bottom of the karst cave. When subsequent layers of filling are constructed, the self-weight of each layer and the construction load are transferred to the bottom through the filling material and borne by the first prestressed anchoring component, thus preventing the filling material from shearing failure or overall subsidence under its own weight.

[0030] Simultaneously, this invention incorporates a second prestressed anchoring assembly corresponding to the number of infill layers. Each set of second prestressed anchoring assemblies penetrates a corresponding layer of infill and anchors into the soil and rock on opposite sides of the karst cave, forming a beaded anchoring structure. This ensures that each layer of infill, after solidification, is no longer an isolated block but rather forms an integrated load-bearing system with the stable soil and rock on both sides of the karst cave through multiple penetrating second prestressed anchor rods. Since there is no need to excavate the slope surface to expose the karst cave, the original stress balance state and soil structure of the slope are preserved to the greatest extent, avoiding collapse accidents caused by soil instability at the top of the karst cave during excavation.

[0031] Furthermore, the layered filling and layered anchoring design allows each layer of filling to bear load independently. Even if a local defect occurs in a certain layer of filling during construction, it will not affect the load-bearing capacity of other layers, and the redundancy and safety of the overall structure are significantly improved. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the first layer filling process of the slope concealed karst cave filling structure of the present invention; Figure 2 This is a schematic diagram of the second layer filling process of the slope concealed karst cave filling structure of the present invention; Figure 3 This is a schematic diagram of the completed state of the slope concealed karst cave filling structure of the present invention; Figure 4 This is a schematic diagram of the method flow of the present invention.

[0033] Among them, 1. The first prestressed anchoring component; 2. Caves; 3. Filler; 4. Second prestressed anchoring assembly.

[0034] The accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The same or similar reference numerals correspond to the same or similar parts. The terms describing positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and technical means in the embodiments of this application can be combined with each other, and the detailed descriptions in the specific embodiments should be understood as explanations of the purpose of this application and should not be regarded as undue limitations on this application.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the specific technical solutions of this application will be further described in detail below with reference to the accompanying drawings of the embodiments of this application. The following embodiments are used to illustrate this application, but are not intended to limit the scope of this application.

[0037] In the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical means indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0038] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0039] In embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0040] The technical solution of this embodiment will be described in detail below with reference to the accompanying drawings.

[0041] Example 1 This embodiment provides a slope concealed karst cave filling structure. For example... Figures 1 to 3 As shown, the slope concealed karst cave filling structure includes: a first prestressed anchoring component 1, a multi-layer filling body 3, and multiple second prestressed anchoring components 4.

[0042] The first prestressed anchoring component 1 is installed in the rock and soil mass at the bottom of the karst cave 2. Specifically, the first prestressed anchoring component 1 consists of four first prestressed anchor rods, which are arranged at intervals along the horizontal direction and distributed in a rectangular pattern within the projected area at the bottom of the karst cave. Each first prestressed anchor rod is anchored in the stable rock and soil mass below the bottom of the karst cave, and each first prestressed anchor rod is prestressed and locked by an anchor, forming a bottom group anchor structure that can provide uniform bearing reaction force within the area at the bottom of the karst cave.

[0043] The multi-layered filling material 3 fills the cavity of the karst cave 2 in layers from bottom to top. In this embodiment, a total of 5 layers of filling material are set according to the height of the karst cave and construction requirements. Each layer of filling material is formed by the curing of cementitious materials such as fine concrete or cement slurry. There is no interlayer between adjacent layers of filling material, and the upper layer of filling material is directly poured on top of the lower layer of cured filling material to form a continuous whole.

[0044] Multiple second prestressed anchoring components 4 correspond to the number of infill layers 3, meaning that one set of second prestressed anchoring components 4 is provided for each layer of infill. In this embodiment, there are a total of 5 sets of second prestressed anchoring components 4. Each set of second prestressed anchoring components 4 penetrates the corresponding layer of infill and is anchored into the rock and soil on both sides of the karst cave 2. Specifically, each set of second prestressed anchoring components 4 includes 3 second prestressed anchor rods, which are arranged at intervals in the horizontal direction. The rod of each second prestressed anchor rod penetrates the entire thickness of the corresponding layer of infill, and its two ends are anchored into the stable rock and soil on both sides of the karst cave 2, forming a "beaded" anchoring structure. Each second prestressed anchor rod is prestressed and locked by an anchor.

[0045] like Figure 1 As shown, the first layer of filler 31 and its corresponding second prestressed anchor constitute the bottom stabilizing unit; as Figure 2 As shown, the second layer of infill 32 and its corresponding second prestressed anchor rod constitute the second layer of stabilizing unit; and so on up to... Figure 3 The fifth layer of infill material 35 and its corresponding second prestressed anchor rod are shown. The second prestressed anchor rods in adjacent layers of infill material are staggered in horizontal projection to avoid the upper and lower anchor rods being on the same vertical line, thereby forming a spatial network reinforcement system within the cavity of the karst cave.

[0046] Example 2 like Figure 4 As shown in the figure, this embodiment provides a method for filling hidden karst caves on slopes. Taking a highway slope project as an example, the geological survey report shows that there is a hidden karst cave 2 inside the slope. The karst cave 2 is not exposed on the slope surface, and the bottom of the karst cave is moderately weathered limestone with good rock mass integrity.

[0047] Before construction, the exact location, geometric dimensions, and surrounding soil and rock conditions of karst cave 2 were determined based on the geological survey results. Based on the cave's dimensions and slope stability requirements, design calculations for the filling treatment were performed to determine the number of filling layers, the height of each layer, anchor bolt arrangement parameters, and the mix ratio of the filling material.

[0048] Step S1: Arrange the first prestressed anchoring component 1 in the rock and soil mass at the bottom of the karst cave 2, specifically: Based on the geological survey results, the location of the bottom of cave 2 was determined. An anchor drilling rig was used to drill a hole horizontally (or slightly downward at 5°~10°) into the slope surface, penetrating the slope's rock and soil mass and entering the stable rock and soil mass below the bottom of the cave. The drilling depth must penetrate the vertical projection area of ​​the bottom of cave 2 and enter the stable rock and soil mass below the bottom by at least 3.0m to ensure that the anchoring section is located in stable strata.

[0049] In this embodiment, the borehole diameter is 110mm, the borehole spacing is 1.2m, and a total of 4 boreholes are arranged in a rectangular pattern within the projection area of ​​the bottom of the karst cave. After drilling is completed, high-pressure air is used to clean the boreholes and remove rock powder and accumulated water.

[0050] The first prestressed anchor rod is inserted. The anchor rod is made of φ25mm precision-rolled threaded steel bar and is 6.0m long (3.0m for the anchorage section and 3.0m for the free section). Before inserting the anchor rod, a centering bracket is installed on the rod to ensure that the anchor rod is centered in the borehole. After the anchor rod is inserted, M30 cement mortar is injected into the borehole at a pressure of 0.3~0.5MPa. The grouting volume is determined by the amount of grout returning from the borehole opening.

[0051] After the grout reaches a strength of 15 MPa (approximately 3-5 days of curing), apply a prestress of 80 kN to the first prestressed anchor rod and lock it in place using an anchorage. At this point, the construction of the first prestressed anchoring assembly 1 is complete. This assembly consists of four first prestressed anchor rods spaced horizontally, forming a bottom group anchor structure that can provide uniform bearing reaction force within the bottom area of ​​the karst cave.

[0052] Step S2: Divide the cavity of cave 2 into multiple filling layers, specifically: Based on the height of the karst cave, and considering the pouring capacity and setting time of the fine concrete used as filling material, as well as the slope's load-bearing safety during construction, the karst cave is divided into five filling layers. The division principle is as follows: the height of each layer should ensure that the slope can withstand the load safely before the filling material solidifies and bears the stress, and before the subsequent anchor bolts are applied prestress. In this embodiment, each filling layer, once completed, possesses a certain load-bearing capacity, capable of bearing the load during the construction of the upper filling layer, ensuring slope stability throughout the entire construction process.

[0053] Step S3: Use the filler 3 and the second prestressed anchoring component 4 to fill the cavity of the sinkhole 2 from bottom to top. Specifically: First, the construction of the first layer of infill material 3 is carried out.

[0054] Step S31: Drill holes in the current fill layer to form beaded anchor holes: The drilling location is determined according to the design, and drilling is carried out from the slope surface or the side of the cave. The borehole diameter is 90mm, and the drilling direction is perpendicular to the cave wall (i.e., horizontal or slightly downward inclined), so that the borehole penetrates the cave 2 and extends into the rock and soil mass on the opposite side of the cave 2, with a depth of not less than 2.5m into the stable rock and soil mass on the opposite side.

[0055] In this embodiment, a set of second prestressed anchoring components 4 is arranged corresponding to the first layer of filling material. This set of components includes three second prestressed anchor rods, arranged at 1.2m intervals along the horizontal direction. Each second prestressed anchor rod corresponds to a drilled hole.

[0056] Drilling was carried out using an anchor drilling rig. The drill bit penetrated the slope side rock and soil mass → entered the karst cave cavity → passed through the karst cave cavity → entered the opposite side rock and soil mass → drilled to the designed depth (2.5m into the opposite side stable rock and soil mass). After drilling was completed, high-pressure air was used to clean the hole. At this point, the borehole connected the stable rock and soil mass on both sides of the karst cave, forming a "beaded" anchor hole, that is, a second prestressed anchor rod will sequentially pass through the slope side rock and soil mass, the current filling layer space, and the opposite side rock and soil mass.

[0057] Step S32: Insert the second prestressed anchor rod into the borehole and pre-drill a grouting hole: The second prestressed anchor rod uses φ20mm precision rolled threaded steel bars, and its length is determined based on the width of the karst cave plus the anchoring sections on both sides.

[0058] Before inserting the anchor bolt, install a positioning bracket on the bolt body to ensure that the anchor bolt is centered in the borehole. After the anchor bolt is inserted, pre-bury a φ15mm plastic pipe next to the anchor bolt as a grouting hole. The lower end of the grouting hole extends to the bottom of the borehole, and the upper end protrudes from the top surface of the current filling layer (i.e., protruding from the top of the karst cave or extending from the slope surface) to facilitate subsequent grouting operations.

[0059] Step S33: Inject filler 3 through the grouting hole, and stop grouting after the grouting volume reaches the designed height. In this embodiment, filler 3 is made of fine concrete. The mix ratio is cement:sand:stone:water = 1:2:2.5:0.5 (by weight), and the slump is controlled at 180mm ± 20mm, exhibiting good fluidity and pourability.

[0060] Fine concrete is injected into the grouting hole using a grouting pump. The grouting pressure is controlled at 0.3~0.5MPa, and the grouting process should be continuous and uniform, avoiding interruptions. The fine concrete gradually rises from the bottom of the borehole, first filling the borehole, and then diffusing into the cavity from the connection between the borehole and the karst cave.

[0061] During grouting, the changes in grouting pressure and volume should be closely monitored. Grouting should be stopped when the grout level rises to the designed height of the first layer. At this point, the first layer of space inside the borehole and the cavity of the karst cave is completely filled with fine concrete, and the three second prestressed anchor rods are completely encased in fine concrete.

[0062] Step S34: After the current filling layer 3 reaches the design strength, apply prestress to the second prestressed anchor rod: In this embodiment, the fine concrete was cured at 20°C. During curing, the surface of the filler should be kept moist to prevent shrinkage cracking. After 7 days of curing, on-site samples were taken to test the compressive strength of the fine concrete, which reached 25 MPa, meeting the design strength requirements.

[0063] At this point, a prestress of 60 kN is applied to each of the three second prestressed anchor rods in the first layer. Tensioning is performed using a through-type jack, with each stage held for 5 minutes. After stabilization, the anchors are locked. After prestressing, the infill material is compressed by the anchor rods, making it tightly contact the cave wall and eliminating gaps between the infill material and the surrounding rock. Simultaneously, the anchoring section of the anchor rod is located in the stable rock and soil on the opposite side, forming a stable anchoring end and providing continuous anchoring force to the infill material.

[0064] At this time, as Figure 1 As shown, the first layer of infill material 3 and its corresponding second prestressed anchor rod have been completed. The lower part of the karst cave has been reinforced, forming a stable structure that can bear loads independently.

[0065] Step S35: Repeat S31 to S34 to complete the second layer (e.g.) Figure 2 (as shown) to the fifth floor (as shown) Figure 3 (As shown) Infill construction. It is important to note that the drill holes in adjacent infill layers should be staggered to avoid the second prestressed anchor rods of the upper and lower layers being on the same vertical line, so as to form a more uniform reinforcement effect.

[0066] Example 3 This embodiment is basically the same as Embodiment 2, except that the filling material 3 uses cement grout instead of fine concrete, and the karst cave 2 has the characteristic of developing fissures. Taking a railway slope project as an example, during the investigation, a hidden karst cave 2 was discovered, and there are multiple fissures on the wall of the karst cave 2 extending to the surrounding rock mass.

[0067] Because of the cracks in the cave walls, direct grouting could lead to significant cement slurry loss, wasting materials and affecting the filling effect. Therefore, before step S33 (injecting the filler through the grouting holes and stopping grouting after reaching the designed height), crack sealing is performed: a layer of cement mortar approximately 30mm thick is sprayed onto the cave walls as a grout-stopping layer to seal the surface cracks. Subsequent grouting operations are then carried out after the grout-stopping layer has initially set (approximately 2 hours).

[0068] In this embodiment, the filler 3 is made of cement grout. During the grouting process, due to the good fluidity of the cement grout, it not only fills the cavity of the karst cave, but also penetrates into the surrounding fissures through pressure. After the grout diffuses and solidifies in the fissures, it forms a reinforcing ring, which further improves the integrity of the surrounding rock.

[0069] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A slope concealed karst cave filling structure, characterized in that, include: The first prestressed anchoring component (1) is installed in the rock and soil mass at the bottom of the karst cave (2); Multi-layer filling body (3), each of the filling bodies (3) is filled in the cavity of the cave (2) from bottom to top; Multiple second prestressed anchoring components (4), the number of which corresponds to the number of the filling body (3); one of the second prestressed anchoring components (4) penetrates one layer of the filling body (3) and is anchored into the rock and soil on opposite sides of the karst cave (2).

2. The slope concealed karst cave filling structure according to claim 1, characterized in that, The first prestressed anchoring assembly (1) includes a first prestressed anchor rod.

3. The slope concealed karst cave filling structure according to claim 2, characterized in that, The first prestressed anchor rod consists of multiple rods, which are arranged at intervals along the horizontal direction.

4. The slope concealed karst cave filling structure according to claim 1, characterized in that, Each of the second prestressed anchoring components (4) includes a second prestressed anchor rod.

5. The slope concealed karst cave filling structure according to claim 4, characterized in that, The second prestressed anchor rod is a plurality of rods, which are arranged at intervals along the horizontal direction; each second prestressed anchor rod penetrates the filling body (3) of the corresponding layer and is anchored into the rock and soil on both sides of the karst cave (2).

6. The slope concealed karst cave filling structure according to claim 1, characterized in that, Each of the fillers (3) is a cementing material.

7. The slope concealed karst cave filling structure according to claim 6, characterized in that, Each of the aforementioned fillers (3) is fine concrete.

8. The slope concealed karst cave filling structure according to claim 6, characterized in that, Each of the fillers (3) is cement slurry.

9. A method for filling concealed karst caves on slopes, used to achieve the structure described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Arrange the first prestressed anchoring component (1) in the rock and soil mass at the bottom of the karst cave (2); S2. Divide the cavity of the cave (2) into multiple filling layers; S3. The cavity of the sinkhole (2) is filled from bottom to top using the filler (3) and the second prestressed anchoring assembly (4); the second prestressed anchoring assembly (4) includes multiple second prestressed anchor rods.

10. The method for filling concealed karst caves on slopes according to claim 9, characterized in that, Step S3 specifically includes: S31. Drill holes in the current filling layer so that the holes penetrate the karst cave (2) and extend into the rock and soil on the opposite side of the karst cave (2) to form a beaded anchor hole. S32. Insert the second prestressed anchor into the borehole and reserve a grouting hole in the current filling layer; S33. Inject the filler (3) through the grouting hole, and stop grouting after the grouting volume reaches the designed height; S34. After the filler (3) of the current filling layer reaches the design strength, prestress is applied to the second prestressed anchor rod; S35. Repeat S31 to S34 until all infill layers are completed.

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