A method for filling a karst cave in a construction of a punched cast-in-place pile

Abstract

The present application relates to the technical field of punched filling pile construction, and discloses a method for filling a karst cave in punched filling pile construction, comprising the following steps: after breaking the top of the karst cave, backfilling mixed materials into the pile hole, using a punch hammer to repeatedly impact and extrude, and extruding the mixed materials into the cavity of the karst cave to densely fill; after the last backfilling impact and extrusion is completed, backfilling again to make the mixed materials higher than the top of the karst cave by a preset height to form a counter-pressure layer; drilling multiple grouting holes at a preset distance from the edge of the pile hole, and extending the depth to the filling area of the karst cave; injecting consolidated slurry into the filling area of the karst cave through the grouting holes; and making the mixed materials consolidated to form a high-strength filling body. The present application combines physical filling and chemical grouting for the first time, the counter-pressure layer prevents the upward migration of grouting slurry, ensures the uniform consolidation of the filling body, has the advantages of simple construction, rapid consolidation, low cost, and reliable quality, and is especially suitable for the construction of punched filling piles in complex karst areas.

Description

Technical Field

[0001] This invention relates to the field of bored pile construction technology, specifically to a method for filling karst caves during bored pile construction. Background Technology

[0002] In karst landform areas, the development of underground hidden karst caves poses a significant technical challenge to borehole construction. Karst caves are underground cavities formed by the long-term dissolution of carbonate rock strata by groundwater. They are characterized by random distribution, highly irregular spatial morphology, vastly different sizes (ranging from centimeters to tens of meters), and complex internal filling states (unfilled, partially filled, or fully filled). When the bored pile breaks through the top of a karst cave, the presence of the cave cavity causes a massive and instantaneous loss of mud used for wall protection and slag removal within the borehole. This leads to a sharp drop in the fluid level inside the hole, and the borehole wall is prone to collapse after losing the pressure support of the mud. Simultaneously, the hammer may deviate or become stuck due to the sudden change in force at the moment of penetration, or even fall or become buried. This not only severely restricts the construction progress and increases costs but may also cause irreversible losses such as the abandonment of the borehole and defects in the pile body.

[0003] Currently, the following measures are mainly adopted to deal with the situation of encountering karst caves during the construction of bored piles: 1. Grouting and filling method: Cement grout is injected into the karst cave through drilling. The fluidity and cementing properties of cement grout are used to fill the karst cave and consolidate the surrounding rock and soil. It has a certain effect on unfilled or semi-filled karst caves. However, ordinary cement grout is easy to diffuse and lose in the karst cave, has a long solidification time, and requires special grouting equipment and grouting holes, resulting in high construction costs. If the karst cave is connected to an underground river, the grout loss will be huge. 2. Casing method: Multi-layer steel casing is used to pass through the karst cave area. The physical shielding effect of the steel casing is used to isolate the karst cave. It is reliable for treating large karst caves. However, the amount of steel used for the casing is large, the installation is difficult, and when the karst cave is too deep, the casing cannot be installed in one go. The overall cost is expensive and the economy is poor. Summary of the Invention

[0004] The purpose of this invention is to provide a structure and method for filling hidden karst caves on slopes, so as to solve the problems of high cost, low efficiency and poor reliability in the treatment of karst caves in the construction of bored piles in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for filling karst caves during the construction of bored cast-in-place piles includes the following steps: S1. After the bored pile construction breaks through the top of the karst cave, the mixed material is backfilled into the pile hole. The mixed material is repeatedly impacted and squeezed by the hammer to squeeze the mixed material into the cavity of the karst cave to fill the karst cave densely. S2. After the final backfilling impact compression is completed, the mixture is backfilled into the pile hole again so that the mixture is higher than the preset height of the top of the karst cave, forming a counter-pressure layer; S3. After the counter-pressure layer is formed, a plurality of grouting holes are drilled at a preset distance from the edge of the pile hole, and the depth of each grouting hole extends to the filling area inside the karst cave. S4. Inject consolidation grout into the filling area of ​​the karst cave through each of the grouting holes, so that the mixture is consolidated to form a high-strength filler.

[0006] Based on the aforementioned technical means, this invention firstly, by repeatedly backfilling the mixture and using a hammer to impact and compress it, effectively squeezes the mixture into the irregular cavities of the karst cave, achieving dense physical filling of the karst cave. Secondly, after the final backfilling and impact compression, the mixture is backfilled into the pile hole again, with the mixture exceeding the cave top by a predetermined height to form a counter-pressure layer. This counter-pressure layer effectively prevents the consolidation grout from flowing upwards along the pile hole wall during subsequent grouting, limiting the grout from filling the karst cave cavity and penetrating downwards, thereby ensuring the uniformity and density of the grouting. Thirdly, by drilling multiple grouting holes at a predetermined distance outside the pile hole edge and injecting consolidation grout, the filled mixture can be actively chemically reinforced, allowing the originally loose mixture to quickly solidify into a high-strength filler, shortening the construction waiting time and improving the overall strength and stability of the filler. Finally, this invention does not require complex and expensive steel casings or large amounts of pure cement grouting; the materials are widely available, the construction process is simple, and while ensuring the treatment effect, it reduces construction costs and has high applicability.

[0007] Furthermore, it also includes: S0, determining the distribution location, scale, shape, and thickness of the cave roof based on the geological survey report data.

[0008] Based on the aforementioned technical methods, the distribution location, scale, shape, and thickness of the cave roof can be determined in advance using geological survey report data. This allows for a visual prediction of the hidden underground cave conditions before construction, providing a scientific basis for determining construction parameters such as the amount of backfill material, the number of impacts, and the location and depth of grouting holes in subsequent steps S1 to S4. This avoids the risks of grout leakage, hole collapse, and hammer jamming caused by blind operation due to a lack of understanding of the cave distribution in traditional construction. It enables differentiated design for different cave shapes and scales, realizing a shift from "experience-based construction" to "data-driven construction," improving the accuracy and success rate of construction. Furthermore, by pre-knowling the thickness of the cave roof, the timing of cave roof penetration and water inflow during drilling can be accurately predicted, allowing for advance emergency response preparations and reducing the occurrence of unexpected accidents. In conjunction with steps S1 to S4, a complete technical chain of "pre-judgment, then filling, and finally consolidation" is formed, ensuring treatment quality while reducing construction risks and material waste.

[0009] Furthermore, S0 specifically refers to: establishing a three-dimensional geological model based on geological survey report data using a BIM platform, including the distribution location, scale, shape, and thickness of the cave roof of the karst cave.

[0010] Based on the aforementioned technical means, firstly, by importing geological survey report data into the BIM platform to establish a three-dimensional geological model, the spatial distribution, geometric shape, size, and changing trend of cave roof thickness of karst caves can be intuitively displayed. This overcomes the shortcomings of traditional two-dimensional geological profile maps, which are not intuitive and lack information continuity. It achieves "visualized decision-making" for the geological conditions of hidden karst caves. The three-dimensional model can clearly present the distribution characteristics of karst caves along the pile's crossing path, assisting construction personnel in accurately predicting the location of cave roof penetration and water inflow that may be encountered during the drilling process. This allows for the early development of differentiated treatment plans for different layers and sections, reducing construction blindness and engineering risks. It forms a complete technical chain of "visualized prediction - precise backfilling - balanced grouting," improving the success rate and construction efficiency of karst cave treatment. It is especially suitable for bored pile construction under difficult geological conditions such as complex karst cave development and multiple layers of overlapping karst caves. Among these, the BIM platform is a software platform based on Building Information Modeling (BIM) technology, which can be used in various stages of building design, construction, operation, and maintenance.

[0011] Furthermore, the mixture is a mixture of graded granite and clay.

[0012] Based on the aforementioned technical methods, graded granite possesses the characteristics of reasonable particle size distribution, high hardness, weather resistance, and good underwater stability. It can form a skeleton-filler composite structure with clay. The graded granite, as coarse aggregate, provides a rigid supporting skeleton, while clay, as fine aggregate, fills the gaps between the skeletons. The synergistic effect of the two improves the compactness and compressibility of the mixture. During repeated impact and extrusion, it can form lower porosity and higher bulk density, thereby filling the irregular cavities of the karst cave and preventing excessive grout loss during subsequent grouting. Clay has good plasticity and cohesion, and can tightly interlock with granite particles during impact and extrusion to form a filler with a certain initial strength, providing a good foundation for subsequent grouting consolidation. The material is readily available and inexpensive, reducing material costs and construction difficulty.

[0013] Furthermore, in step S2, the preset height is 1m.

[0014] Based on the above technical means, setting the height of the counterpressure layer to 1m can form sufficient pressure resistance to prevent the consolidation grout from flowing upward along the pile hole wall during subsequent high-pressure grouting, restrict the grout from filling the cavities of the karst cave and penetrating downward, and ensure the uniformity of grouting and the overall consolidation quality of the filling body. Under the premise of ensuring the grouting counterpressure effect, the amount of mixing material is reduced.

[0015] Furthermore, in step S3, the preset distance is 1m.

[0016] Based on the above technical means, the distance between the grouting hole and the edge of the pile hole is set to 1m. This ensures that there is a sufficient safe distance between the grouting hole and the pile hole to avoid damage or disturbance to the already formed pile hole wall during drilling. It also ensures that the distance between the grouting hole and the karst filling area is appropriate, so that the injected consolidation grout can diffuse into the karst filling body under reasonable pressure and form a uniform consolidation effect.

[0017] Furthermore, in step S3, there are three grouting holes, and each grouting hole is evenly distributed along the circumference of the pile hole.

[0018] Based on the above technical means, the number of grouting holes is three and they are evenly distributed along the circumference of the pile hole, which realizes balanced high-pressure grouting of the karst cave filling area. The consolidation grout can be injected into the filling body simultaneously from three different directions, ensuring that the grout diffuses evenly in the karst cave cavity and fills without dead corners, avoiding problems such as grout deviation and uneven filling that are easy to occur with single-hole or double-hole grouting.

[0019] Furthermore, in step S4, the consolidation grout is a mixture of cement grout and water glass.

[0020] Based on the above-mentioned technical means, a two-liquid slurry formed by mixing cement slurry and water glass is used as the consolidation slurry. After mixing, water glass and cement slurry undergo a rapid chemical reaction to generate hydration products such as calcium silicate gel, which can quickly bind loose graded granite and clay mixture together to form a solidified body with high strength, meeting the requirements of lateral extrusion by hammer, without the need for long-term downtime to wait for strength growth. Water glass acts as a quick-setting agent, and its dosage can be adjusted to flexibly control the gelation time of the mixture. Compared with single cement slurry, the solidification time of the mixture can be flexibly controlled from several minutes to tens of minutes by adjusting the amount of water glass, avoiding the problem of pure cement slurry diffusing and losing a large amount in the karst cave due to its high fluidity and slow solidification, reducing slurry loss and lowering grouting costs.

[0021] Furthermore, it also includes: S5, after grouting is completed, injecting mud into each of the grouting holes.

[0022] Based on the above-mentioned technical means, after grouting is completed, mud is injected into each grouting hole. The mud's suspension and wall-protecting effect forms a mud cake on the hole wall, preventing the grouting hole from collapsing and blocking due to hole wall instability during subsequent construction. This ensures the long-term unobstructed flow of the grouting channel. Furthermore, when encountering multi-layered karst caves that require tiered treatment, the grouting holes that have been protected by mud can be directly reused without the need for re-drilling, reducing drilling workload and construction time, and lowering the consumption of manpower and resources.

[0023] Furthermore, when encountering multiple layers of karst caves, after completing the treatment of the previous layer of karst cave, construction continues downward along the pile hole to the top of the next layer of karst cave. Then, steps S1 to S4 are repeated, treating each layer until the bored pile reaches the designed depth.

[0024] Based on the aforementioned technical means, when encountering multi-layered karst caves, the complex geological problems of multi-layered karst caves are decomposed into standardized procedures for multiple single-layered karst caves through a cyclical operation mode of "completing one layer, treating one layer, and then constructing the next layer downwards." This allows for the continued construction downwards along the pile hole to the top of the next layer of karst cave, making full use of the already treated upper-layer karst cave filling as a stable bearing layer and protective barrier for subsequent construction. This prevents risks such as grout leakage and hole collapse that may occur during the treatment of lower-layered karst caves, improves construction efficiency, and realizes a closed-loop operation from prediction to treatment, and from single-layer to multi-layered processes. This enhances the adaptability and engineering practicality of the invention to complex karst geological conditions.

[0025] The beneficial effects achieved by this invention are as follows: This invention firstly, by repeatedly backfilling the mixture and using a hammer to impact and compress it, the mixture can be effectively squeezed into the irregular cavities of the karst cave, achieving dense physical filling of the karst cave. Secondly, after the final backfilling and impact compression, the mixture is backfilled into the pile hole again, making the mixture higher than the top of the karst cave by a predetermined height to form a counter-pressure layer. This counter-pressure layer effectively prevents the solidified grout from flowing upwards along the pile hole wall during subsequent grouting, limiting the grout from filling the karst cave cavities and seeping downwards, thereby ensuring the uniformity and density of the grouting. Thirdly, through the pile hole... Multiple grouting holes are drilled at a predetermined distance on the outer edge and consolidation grout is injected, which can actively chemically reinforce the filled mixture, so that the originally loose mixture can be quickly consolidated into a high-strength filler, shortening the construction waiting time and improving the overall strength and stability of the filler. Finally, this invention does not require the use of complex and expensive steel casings or large amounts of pure cement grouting. The materials are widely available and the construction process is simple. While ensuring the treatment effect, it reduces the construction cost and has high applicability, especially suitable for bored pile construction in complex karst areas. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the process of breaking through karst caves during the construction of bored piles according to the present invention. Figure 2 This is a schematic diagram illustrating the process of repeated impact and extrusion of the backfill material mixture into the pile hole according to the present invention. Figure 3 This is a schematic diagram illustrating the process of injecting consolidation grout into the karst cave filling area through grouting holes according to the present invention. Figure 4 This is a schematic diagram of the multi-layered karst cave treatment process of the present invention; Figure 5 This is a schematic diagram illustrating the completion of multi-layer karst cave treatment during the construction of bored cast-in-place piles according to the present invention.

[0027] Among them, 1-pile hole; 2-karst cave; 3-impact hammer; 4-mixing material; 5-grouting hole; 6-consolidation grout.

[0028] 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

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The technical solution of this embodiment will be described in detail below with reference to the accompanying drawings.

[0035] Example 1 This embodiment provides a method for filling karst caves during bored pile construction, specifically for single-layer karst caves encountered during bored pile construction in karst landform areas; such as... Figure 1 As shown, it includes the following steps: S0. Based on the geological survey report data, a three-dimensional geological model containing the distribution location, scale, shape and thickness of the cave roof of cave 2 is established using the BIM platform to determine the distribution location, scale, shape and thickness of the cave roof of cave 2. S1. After the bored pile construction breaks through the top of the karst cave 2, the mixture 4 is backfilled into the pile hole 1. The mixture 4 is repeatedly impacted and squeezed by the hammer 3 to squeeze the mixture 4 into the cavity of the karst cave 2 to fill the karst cave 2 densely. S2. After the final backfilling impact compression is completed, mix material 4 is backfilled into pile hole 1 again so that mix material 4 is higher than the preset height of the top of the karst cave 2, forming a counter-pressure layer; S3. After the counter-pressure layer is formed, multiple grouting holes 5 are drilled at a preset distance from the edge of the pile hole 1, and the depth of each grouting hole 5 extends to the filling area inside the karst cave 2. S4. Inject solidification grout 6 into the filling area of ​​the karst cave 2 through each grouting hole 5, so that the mixture 4 is solidified to form a high-strength filling body. S5. After grouting is completed, inject mud into each grouting hole 5.

[0036] In a preferred embodiment of this invention, the mixing material 4 is a mixture of graded granite and clay; in step S2, the preset height is 1m; in step S3, the preset distance is 1m; the number of grouting holes 5 is 3, and each grouting hole 5 is evenly distributed along the circumference of the pile hole 1; in step S4, the consolidation grout 6 is a mixture of cement grout and water glass.

[0037] This embodiment, based on the technical logic of "predictive guidance—composite filling—controllable grouting—rapid consolidation—protection of grouting hole 5", solves the problems of grout leakage, hole collapse, hammer jamming, and pile defects that occur in the construction of bored piles in strata with developed karst caves 2. In practical application, before the construction of bored piles, a geological survey is first carried out in the area of ​​the bored pile location to obtain geological survey report data, which usually includes information such as borehole columnar section, rock and soil layer distribution, location of karst cave 2, thickness of the top plate of karst cave 2, height of karst cave 2, and properties of the filling material inside karst cave 2. The acquisition and interpretation of geological survey report data are conventional technical means for those skilled in the art, and will not be elaborated here.

[0038] Specifically, in this embodiment, firstly, based on the geological survey report data, it is determined that there is a layer of karst cave 2 below the pile location to be constructed, and the distribution location, scale, shape, and top thickness of karst cave 2 are obtained; further, the geological survey report data is imported into the BIM platform, and a three-dimensional geological model containing the distribution location, spatial shape, scale, and top thickness of karst cave 2 is established using BIM software (such as Autodesk Revit, Bentley, etc.) to intuitively observe the distribution characteristics of karst cave 2 along the pile's crossing path, and to help predict the specific location of the karst cave 2 top that will be penetrated during the drilling process, as well as the possible water inflow and mud loss after penetration, providing a basis for setting subsequent backfilling and grouting parameters; Then, following the conventional bored pile construction process, the bored pile machine was installed, and the boring operation began; such as Figure 2 As shown, after breaking through the top of the karst cave 2, the hammer 3 is raised, and a mixture of graded granite and clay in a 1:1 weight ratio (4) is immediately backfilled into the pile hole 1. The initial backfill height exceeds the top of the karst cave 2 by 50-80 cm. Then, the hammer 3 is lowered to impact and compress the mixture 4, forcibly squeezing it into the irregular cavity of the karst cave 2. As the mixture 4 is squeezed in, the elevation of the mixture 4 surface in the hole drops. At this time, the mixture 4 is backfilled again, and the impact and compression continue. This cycle of "backfilling-impacting-compacting" is repeated, so that the mixture 4 is accumulated and compacted layer by layer in the karst cave 2, forming a dense filling body, until the hammer 3 feels a significant increase in resistance during the impact process, and the surface of the mixture 4 in the hole no longer drops significantly, indicating that the cavity of the karst cave 2 has been basically filled with the mixture 4. After confirming that the cavity of karst cave 2 has been densely filled, a final backfill is carried out, allowing the mixture 4 to naturally accumulate at the bottom of the pile hole 1, exceeding the preset height of the top of karst cave 2. In this embodiment, the preset height is 1m, that is, the height of the counter-pressure layer is 1m. During the subsequent grouting process, the downward pressure generated by its own weight and density prevents the grout from flowing upward along the wall of the pile hole 1, forcing the grout to fill the cavity of karst cave 2 and penetrate downward, thereby ensuring the grouting quality. After the counter-pressure layer is formed, grouting holes 5 are drilled on the outer edge of the pile hole 1. In this embodiment, three grouting holes 5 are drilled at a preset distance of 1m from the center of the pile hole 1. Each grouting hole 5 is evenly distributed around the pile hole 1 and its depth needs to extend into the filling area inside the karst cave 2. After drilling grouting hole 5, install the grouting equipment, such as... Figure 3 As shown, a solidification grout 6 is injected under high pressure into the filling area of ​​the karst cave 2 through each grouting hole 5. In this embodiment, the solidification grout 6 is a mixture of cement slurry and water glass, wherein water glass acts as a quick-setting agent. The gelation time of the mixture can be flexibly controlled by adjusting its dosage, ranging from a few minutes to tens of minutes. Therefore, in this embodiment, the volume ratio of cement slurry to water glass can be adjusted according to the actual required setting time. Then, the mixture of cement slurry and water glass is injected under high pressure into the filling area of ​​the karst cave 2 through the grouting hole 5 to fully fill the pores of the mixture 4 and react with the granite and clay particles to generate a high-strength, low-permeability filler. The high pressure can be 1.5 MPa, or any pressure value greater than 1.5 MPa can be selected according to the actual construction requirements. After grouting is completed, mud is injected into each grouting hole 5. The mud can be the same clay mud used in drilling. After the mud is injected, a mud cake is formed on the wall of the grouting hole 5 to prevent the hole wall from collapsing and blocking, while preserving the grouting channel. If it is found that the grouting effect of the karst cave 2 in this layer is not ideal and needs to be supplemented, or if there are other karst caves 2 below that need to be treated, the protected grouting hole 5 can be used directly for the operation without re-drilling.

[0039] Example 2 When encountering multi-layered karst caves during bored pile construction in karst landform areas; such as Figure 4 As shown, this embodiment follows steps S1 to S5 of Embodiment 1. Specifically, after completing the treatment of the upper-level karst cave 2, drilling continues downwards along pile hole 1 until the top of the lower-level karst cave 2 is penetrated. Then, steps S1 to S5 are repeated layer by layer until the bored pile reaches the designed depth. Figure 5 As shown.

[0040] 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 method for filling karst caves during the construction of bored cast-in-place piles, characterized in that, Includes the following steps: S1. After the bored pile construction breaks through the top of the karst cave, the mixed material is backfilled into the pile hole. The mixed material is repeatedly impacted and squeezed by the hammer to squeeze the mixed material into the cavity of the karst cave to fill the karst cave densely. S2. After the final backfilling impact compression is completed, the mixture is backfilled into the pile hole again so that the mixture is higher than the preset height of the top of the karst cave, forming a counter-pressure layer; S3. After the counter-pressure layer is formed, a plurality of grouting holes are drilled at a preset distance from the edge of the pile hole, and the depth of each grouting hole extends to the filling area inside the karst cave. S4. Inject consolidation grout into the filling area of ​​the karst cave through each of the grouting holes, so that the mixture is consolidated to form a high-strength filler.

2. The method for filling karst caves during bored pile construction according to claim 1, characterized in that, Also includes: S0. Based on the geological survey report data, determine the distribution location, scale, shape, and thickness of the cave roof of the karst cave.

3. The method for filling karst caves during the construction of bored cast-in-place piles according to claim 2, characterized in that, Specifically, S0 involves using a BIM platform to create a three-dimensional geological model that includes the distribution location, scale, shape, and thickness of the cave roof, based on the geological survey report data.

4. The method for filling karst caves during the construction of bored cast-in-place piles according to claim 1, characterized in that, The mixing material is a mixture of graded granite and clay.

5. The method for filling karst caves during bored pile construction according to claim 1, characterized in that, In step S2, the preset height is 1m.

6. The method for filling karst caves during bored pile construction according to claim 1, characterized in that, In step S3, the preset distance is 1m.

7. The method for filling karst caves during bored pile construction according to claim 1, characterized in that, In step S3, there are 3 grouting holes, and each grouting hole is evenly distributed along the circumference of the pile hole.

8. The method for filling karst caves during the construction of bored cast-in-place piles according to claim 1, characterized in that, In step S4, the consolidation grout is a mixture of cement grout and water glass.

9. The method for filling karst caves during the construction of bored cast-in-place piles according to claim 1, characterized in that, Also includes: S5. After grouting is completed, inject mud into each of the grouting holes.

10. The method for filling karst caves during the construction of bored cast-in-place piles according to claim 1, characterized in that, When encountering multiple layers of karst caves, after completing the treatment of the previous layer of karst caves, continue construction downwards along the pile hole to the top of the next layer of karst caves, and then repeat steps S1 to S4, treating each layer until the bored pile reaches the designed depth.

Images