Bridge pile foundation karst cave treatment method

Abstract

The invention discloses a bridge pile foundation karst cave treatment method, and relates to the technical field of buildings. Comprising the following steps: acquiring three-dimensional model information of a karst cave; determining a filling mode of the karst cave according to the three-dimensional model information of the karst cave; the karst cave is filled according to the filling mode and the corresponding filling slurry; wherein the fluidity of the filling slurry is 220 to 300 mm. The three-dimensional model information of the karst cave is obtained, the karst cave is filled according to the filling mode and the corresponding filling slurry, accurate filling can be conducted according to the actual shape of the karst cave, waste of filling materials is reduced, and localized and quantitative controllable treatment is achieved. The fluidity of the filling slurry is 220-300 mm, so that the filling slurry can be in a flow state and flow among complex gullies in the karst cave, filling of the karst cave is achieved, and the filling strength is improved.

Description

Technical Field

[0001] This application relates to the field of construction technology, and particularly relates to a method for treating karst caves in bridge pile foundations. Background Art

[0002] A karst cave refers to a cavity formed by the long-term dissolution of carbonate rock strata under the action of groundwater when groundwater seeps along the joints or fissures of carbonate rock strata, and exists in the form of karst erosion phenomena such as solution grooves, solution fissures, karst caves, and sinkholes. The karst filling types are complex and diverse in shape, the rock surface has irregular undulations, and the stability of the roof is poor. The above factors result in complex geological and hydrological conditions in the karst cave area, and there are many horizontal and vertical beaded karst caves distributed. Due to the complexity of karst, during the construction of bored cast-in-place piles for bridge pile foundations in developed karst strata, accidents such as slurry leakage from the pile hole, collapse of the hole wall, inclination of the pile hole, ground collapse, and sudden loss of concrete may occur. Blindly carrying out perfusion treatment and pile foundation construction are also extremely likely to cause disasters such as ground collapse and sudden water inrush. And according to the research status of karst cavity treatment technology, it can be found that the existing karst cavity treatment technology is extremely prone to overfilling of perfusion materials, resulting in serious waste of resources. Summary of the Invention

[0003] This application provides a method for treating karst caves in bridge pile foundations to achieve precise treatment of karst caves in pile foundations.

[0004] In a first aspect, this application provides a method for treating karst caves in bridge pile foundations, including the following steps:

[0005] Obtain the three-dimensional model information of the karst cave;

[0006] Determine the filling method of the karst cave according to the three-dimensional model information of the karst cave;

[0007] Fill the karst cave with the corresponding filling slurry according to the filling method;

[0008] Wherein the fluidity of the filling slurry is 220 - 300 mm.

[0009] This application can accurately fill the karst cave by obtaining the three-dimensional model information of the karst cave and filling the karst cave with the corresponding filling slurry according to the filling method, reduce the waste of filling materials, and achieve controllable treatment in a specific area and with a specific quantity. The fluidity of the filling slurry being 220 - 300 mm can make the filling slurry in a fluid state, flow between the complex gullies inside the karst cave, and achieve the filling of the karst cave, improving the filling strength.

[0010] It should be noted that the fluidity of the filling slurry refers to the fluidity of the truncated cone mold. The fluidity of the filling slurry can be measured by the method in "Test Methods for the Homogeneity of Concrete Admixtures" (GB 8077 - 2012).

[0011] In some embodiments, the method for obtaining the three-dimensional model of the karst cave includes combined exploration by the first exploration method, the second exploration method, and the third exploration method, where:

[0012] The first exploration method includes at least one of seismic exploration, electrical exploration, and electromagnetic exploration;

[0013] The second exploration method includes the drilling method;

[0014] The third exploration method includes at least one of the tube wave detection method and the cross-hole nuclear magnetic method.

[0015] The combined exploration by the first exploration method, the second exploration method, and the third exploration method can conduct a detailed investigation and detection of the karst caves in the bridge pile foundation area before construction, intuitively understand the distribution of the karst caves in the karst area, visually reflect the morphology and connectivity of the karst caves, ensure that the design scheme can avoid potential geological risk points, establish a three-dimensional refined model of the karst caves, accurately reconstruct the three-dimensional topography of the karst caves, provide strong support for the karst cave treatment plan, risk disposal, and cost control, and serve as the basis for design and construction, guide numerical simulation tests and scaled indoor tests, test the perfusion effect of grouting the karst caves in sections and subsections, reduce the uncertainty during the construction process, guide the subsequent karst cave treatment plan and the pile foundation construction plan, and ensure construction and operation safety.

[0016] In some embodiments, the three-dimensional model information of the karst cave includes at least one of the distribution of the karst cave, the type of the karst cave, the volume of the karst cave, and the filling type of the karst cave.

[0017] The distribution of the karst cave, the type of the karst cave, the volume of the karst cave, and the filling type of the karst cave are all important components of the three-dimensional model information of the karst cave and affect the filling of the slurry. Among them, the distribution of the karst cave mainly refers to the position of the karst cave boundary in the three-dimensional stratum model. The type of the karst cave mainly refers to independent karst caves, vertical beaded karst caves, and horizontal beaded karst caves. The volume of the karst cave mainly refers to the volume of the karst cave cavity and the volume of the internal filling body of the karst cave. The filling type of the karst cave mainly refers to no filling, semi-filling, and full filling.

[0018] In some embodiments, the filling methods include no filling method, semi-filling method, and full filling method, where:

[0019] The no filling method uses the first slurry for filling;

[0020] The semi-filling method uses the first slurry and the second slurry for filling;

[0021] The full filling method uses the second slurry for filling;

[0022] The first slurry and the second slurry are different.

[0023] The unfilled mode means that the inside of the karst cave is completely empty, without obvious sediments or other filling materials. The semi-filled mode means that the lower part of the karst cave is occupied by sediments, gravel, soil or other materials, but there is still visible space in the upper part that is not filled. The fully filled mode means that the karst cave is completely filled with filling materials such as sediments, rock debris, soil, etc. It seems to be a continuous stratum on the surface, but in fact there is a space that used to be a cavity below. Due to the different filling modes of the karst cave, different slurries can be used for filling to make the strength of the filler consistent after filling.

[0024] The differences between the first slurry and the second slurry are that the first slurry contains coarse particle components such as stone powder and has a higher strength than the second slurry, and is suitable for filling cavity bodies; the second slurry has a small particle size and is easy to be mixed evenly with the karst cave filling body.

[0025] In some embodiments, the determination of the filling mode of the karst cave according to the three-dimensional model information of the karst cave includes:

[0026] If the filling mode of the karst cave is the unfilled mode, the first slurry is used to fill the entire cavity area of the karst cave.

[0027] A karst cave in the unfilled mode means that the entire inside of the karst cave is a cavity area, and there is no additional material to provide strength. Therefore, using the first slurry to fill the entire cavity area of the karst cave can improve the overall strength of the karst cave in the unfilled mode. Specifically, directly use the controllable fluid state solid waste filling material, the first slurry, for green filling treatment. Prepare the slurry with solid waste materials on the ground, lower the perfusion pipe through the drill hole, and then lift the pipe while perfusion until it is lifted more than 0.5 m above the roof of the karst cave.

[0028] In some embodiments, the determination of the filling mode of the karst cave according to the three-dimensional model information of the karst cave includes:

[0029] If the filling mode of the karst cave is the semi-filled mode, the second slurry is used to fill the non-cavity area at the bottom of the karst cave, and then the first slurry is used to fill the cavity area of the karst cave.

[0030] A karst cave in a semi-filled state means that there are some empty areas inside the karst cave and some non-empty areas filled with other materials. In the non-empty areas, some strength is provided by other materials, but the strength may not meet the requirements. Filling the non-empty intervals at the bottom of the karst cave with the second slurry can increase the strength of the non-empty areas. In the empty areas, no additional materials provide strength. Therefore, filling the empty areas of the karst cave with the first slurry can increase the overall strength of the karst cave in the semi-filled state. Specifically, in the non-empty filling area, the second slurry of the mineral waste-based solidifying material is directly used for jet grouting reinforcement treatment. The jet grouting trolley lowers the jet grouting drill rod to the bottom of the filler through the existing borehole and performs rotary jet grouting. Currently, the maximum jet grouting pressure can reach 50 - 60 MPa. In clay, the jet grouting diameter can reach 2 - 3 m, and the specific jet grouting diameter size is determined by the bridge pile diameter and the thickness of the hole wall to be reinforced. The jet grouting reinforcement operation can be completed by jetting and lifting simultaneously to the height of the top of the filler. In the non-filled area, the first slurry of the controllable fluidized solid waste filling material is directly used for green filling treatment. The slurry is prepared with solid waste materials on the ground surface, and the perfusion pipe is lowered through the borehole. Subsequently, the pipe is perfused and lifted simultaneously until it is lifted more than 0.5 m above the roof of the karst cave.

[0031] In some embodiments, the determination of the filling method of the karst cave according to the three-dimensional model information of the karst cave includes:

[0032] If the filling method of the karst cave is the full filling method, the second slurry is used to fill the entire non-empty interval of the karst cave.

[0033] A karst cave in a full-filled state means that the inside of the karst cave is filled with other materials and there are basically no empty areas. The strength of these filling materials usually cannot meet the requirements. By filling the entire non-empty interval of the karst cave with the second slurry, the second slurry can be mixed with the original filling materials, thereby increasing the overall strength of the karst cave in the full-filled state. Specifically, the second slurry of the mineral waste-based solidifying material is directly used for jet grouting reinforcement treatment. The jet grouting trolley lowers the jet grouting drill rod to the bottom of the filler through the existing borehole and performs rotary jet grouting. Currently, the maximum jet grouting pressure can reach 50 - 60 MPa. In clay, the jet grouting diameter can reach 2 - 3 m, and the specific jet grouting diameter size is determined by the bridge pile diameter and the thickness of the hole wall to be reinforced. The jet grouting reinforcement operation can be completed by jetting and lifting simultaneously to the height of the top of the filler.

[0034] In some embodiments, the materials of the first slurry include excavated soil, curing agent, stone powder, alkali activator, early strength agent and water. The first slurry including the above materials can form a certain strength after curing to support the bridge pile foundation, improve the strength of the karst cave, reduce collapse. Among them, the use of excavated soil can avoid material waste and pollution caused by filling the karst cave with materials such as concrete, and realize the filling and consumption of solid waste. The excavated soil can be solid waste filling materials such as topsoil, drilling waste mud, drilling cuttings, etc. The curing agent can cure the slurry, and the curing agent can be at least one of commercially available soil curing agents and sludge curing agents. The stone powder can improve the strength after the slurry hardens, and the stone powder can be at least one of limestone powder and marble powder. The alkali activator can improve the reaction degree of the curing agent, and the alkali activator can be at least one of sodium silicate, calcium hydroxide and sodium hydroxide. The early strength agent can accelerate the hardening of the slurry, and the early strength agent can be at least one of sodium chloride and sodium sulfate; and / or,

[0035] The materials of the second slurry include curing agent, alkali activator, early strength agent and water. The curing agent can be at least one of commercially available soil curing agents and sludge curing agents. The alkali activator can be at least one of sodium silicate, calcium hydroxide and sodium hydroxide. The early strength agent can be at least one of sodium chloride and sodium sulfate. The second slurry including the above materials can penetrate into the karst cave area filled with other materials and cure together with other materials to increase the strength.

[0036] It should be noted that the viscosity of the first slurry is usually greater than that of the second slurry, and the solid content of the first slurry is usually greater than that of the second slurry. The ratio of the first slurry and the second slurry can be selected according to the construction site. The fluidity of the first slurry can be 220 - 280 mm. The fluidity of the second slurry can be 260 - 300 mm.

[0037] In some embodiments, the strength of the first slurry after hardening for 7 days is 0.5 - 3 MPa. The strength of the first slurry after hardening for 28 days is 1 - 5 MPa, and the strength can continue to increase in 1 - 2 years, improving the support for the bridge pile foundation.

[0038] In some embodiments, after the karst cave is filled, the permeability of the filler after hardening for 7 days is 10 -8 ~10 -9 cm / s. The permeability coefficient of natural sandy soil and silt is 10 -5 ~10 -6 cm / s. The permeability coefficient of the karst cave after hardening for 7 days is less than that of natural sandy soil and silt, which can effectively prevent the problems of slurry leakage and filtration loss during the hole formation process of the bridge pile foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0040] Figure 1 It is a flowchart of a method for treating karst caves in bridge pile foundations according to an embodiment of the present application.

[0041] Figure 2 It is a flowchart of a method for treating karst caves in bridge pile foundations according to an embodiment of the present application.

[0042] Figure 3 It is a flowchart of a method for treating karst caves in bridge pile foundations according to an embodiment of the present application.

[0043] Figure 4 It is a flowchart of a method for treating karst caves in bridge pile foundations according to an embodiment of the present application. Detailed implementation manners

[0044] To make the objectives, technical solutions, and advantages of the present application clearer, the following will clearly and completely describe the technical solutions of the present application in combination with the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0045] Karst caves refer to cavities formed by the long-term dissolution of carbonate rock strata under the action of groundwater when groundwater seeps along the joints or fissures of carbonate rock strata, existing in the form of corrosion phenomena such as corrosion grooves, corrosion gaps, karst caves, and sinkholes. The karst filling types are complex, with various shapes, the rock surface is irregularly undulating, and the stability of the roof is poor. The above factors lead to complex geological and hydrogeological conditions in the karst cave area, and there are many horizontal and vertical beaded karst caves distributed. Due to the complexity of karst, during the construction of bored cast-in-place piles for bridge pile foundations in developed karst strata, accidents such as slurry leakage from the pile hole, collapse of the hole wall, inclination of the pile hole, ground collapse, and sudden loss of concrete may occur. Blindly carrying out perfusion treatment and pile foundation construction is also extremely likely to cause disasters such as ground collapse and sudden water inrush. And according to the research status of the karst cavity treatment technology, it can be found that the existing karst cavity treatment technology is extremely likely to cause overfilling of the perfusion materials, resulting in serious waste of resources.

[0046] Therefore, it is necessary to conduct a detailed investigation and detection of the karst caves in the bridge pile foundation area before construction, intuitively understand the distribution of karst caves in the karst area, establish a three-dimensional refined model of the karst caves, and use it as the basis for design and construction to guide the subsequent karst cave treatment plan and pile foundation construction plan to ensure construction and operation safety.

[0047] In addition, a large amount of solid waste such as solid stone, muck, drill cuttings, and construction waste generated during engineering construction and surrounding industrial production, as well as waste slurry during the drilling process, all face the problems of treatment and resource recycling. Currently, the treatment of large karst caves in the bridge pile foundation area basically adopts perfusion treatment, and most of the perfusion materials are cement-based gelling materials such as low-grade concrete and composite paste, which are extremely likely to cause groundwater pollution, and such materials will generate a large strength redundancy.

[0048] In view of this, the present application provides a method for treating karst caves in bridge pile foundations to achieve precise treatment of pile foundation karst caves.

[0049] In the first aspect, as Figure 1 shown, the present application provides a method for treating karst caves in bridge pile foundations, including the following steps:

[0050] S100. Obtain the three-dimensional model information of the karst cave;

[0051] S200. Determine the filling method of the karst cave according to the three-dimensional model information of the karst cave;

[0052] S300. Fill the karst cave with the corresponding filling slurry according to the filling method;

[0053] Wherein, the fluidity of the filling slurry is 220 - 300 mm.

[0054] By obtaining the three-dimensional model information of the karst cave and filling the karst cave with the corresponding filling slurry according to the filling method, precise filling can be carried out according to the actual shape of the karst cave, reducing the waste of filling materials and realizing controllable treatment in a fixed area and with a fixed quantity. The fluidity of the filling slurry being 220 - 300 mm can make the filling slurry in a fluid state, flow between the complex gullies inside the karst cave, achieve the filling of the karst cave, and improve the filling strength.

[0055] It should be noted that the fluidity of the filling slurry refers to the fluidity of the truncated cone mold. The fluidity of the filling slurry can be measured by the method in "Test Methods for the Homogeneity of Concrete Admixtures" (GB 8077 - 2012).

[0056] Combined with the first aspect, in some embodiments provided by the present application, the method for obtaining the three-dimensional model of the karst cave includes joint exploration by the first exploration method, the second exploration method, and the third exploration method, where:

[0057] The first exploration method includes at least one of seismic exploration, electrical exploration, and electromagnetic exploration;

[0058] The second exploration method includes the drilling method;

[0059] The third detection method includes at least one of the tube wave detection method and the cross-hole nuclear magnetic method.

[0060] The combined detection of the first detection method, the second detection method, and the third detection method can conduct a detailed investigation and detection of the karst caves in the bridge pile foundation area before construction, intuitively understand the distribution of karst caves in the karst area, intuitively reflect the morphology and connection of karst caves, ensure that the design scheme can avoid potential geological risk points, establish a three-dimensional refined model of karst caves, accurately reconstruct the three-dimensional topography of karst caves, provide strong support for the karst cave treatment plan, risk disposal, and cost control, and serve as the basis for design and construction, guiding numerical simulation tests and scaled indoor tests, testing the perfusion effect of karst caves filled section by section, reducing the uncertainty during construction, guiding subsequent karst cave treatment plans and pile foundation construction plans, and ensuring construction and operation safety. Among them, seismic exploration includes reflection method, refraction method, surface wave method, and imaging method. Electrical exploration includes electrical profiling method, electrical sounding method, high-density electrical method, natural potential method, and charging method. Electromagnetic exploration includes audio magnetotelluric method, transient electromagnetic method, and ground penetrating radar method.

[0061] Combined with the first aspect, in some embodiments provided by the present application, the three-dimensional model information of the karst cave includes at least one of the distribution of the karst cave, the type of the karst cave, the volume of the karst cave, and the filling type of the karst cave.

[0062] The distribution of the karst cave, the type of the karst cave, the volume of the karst cave, and the filling type of the karst cave are all important components of the three-dimensional model information of the karst cave and affect the filling of the slurry. Among them, the distribution of the karst cave mainly refers to the position of the karst cave boundary in the three-dimensional stratum model. The type of the karst cave mainly refers to independent karst cave, vertical beaded karst cave, and horizontal beaded karst cave. The volume of the karst cave mainly refers to the volume of the karst cave cavity and the volume of the internal filling body of the karst cave. The filling type of the karst cave mainly refers to no filling, semi-filling, and full-filling.

[0063] Combined with the first aspect, in some embodiments provided by the present application, the filling method includes no filling method, semi-filling method, and full-filling method, where:

[0064] The no filling method uses the first slurry for filling;

[0065] The semi-filling method uses the first slurry and the second slurry for filling;

[0066] The full-filling method uses the second slurry for filling;

[0067] The first slurry and the second slurry are different.

[0068] The unfilled mode means that the interior of the karst cave is completely empty, without obvious sediments or other filling materials. The semi-filled mode means that the lower half of the karst cave is occupied by sediments, gravel, soil or other materials, but there is still visible space in the upper half that is not filled. The fully filled mode means that the karst cave is completely filled with filling materials such as sediments, rock debris, soil, etc. It seems to be a continuous stratum on the surface, but actually there is a space that used to be a cavity below. Due to the different filling modes of the karst cave, different slurries can be used for filling to make the strength of the filler after filling consistent.

[0069] The differences between the first slurry and the second slurry are that the first slurry contains coarse-grained components such as stone powder and has a higher strength than the second slurry, which is suitable for filling cavity bodies; the second slurry has a small particle size and is easy to be mixed evenly with the karst cave filling body.

[0070] Combined with the first aspect, as Figure 2 shown, in some embodiments provided by the present application, the determining the filling mode of the karst cave according to the three-dimensional model information of the karst cave includes:

[0071] S301. If the filling mode of the karst cave is the unfilled mode, the entire cavity area of the karst cave is filled with the first slurry.

[0072] A karst cave in the unfilled mode means that the entire interior of the karst cave is a cavity area without additional materials to provide strength. Therefore, filling the entire cavity area of the karst cave with the first slurry can improve the overall strength of the karst cave in the unfilled mode. Specifically, directly use the controllable fluid state solid waste filling material, the first slurry, for green filling treatment. Prepare the slurry with solid waste materials on the ground, lower the perfusion pipe through drilling, and then lift the pipe while perfusion until it is lifted more than 0.5 m above the roof of the karst cave.

[0073] Combined with the first aspect, as Figure 3 shown, in some embodiments provided by the present application, the determining the filling mode of the karst cave according to the three-dimensional model information of the karst cave includes:

[0074] S302. If the filling mode of the karst cave is the semi-filled mode, the non-cavity area at the bottom of the karst cave is filled with the second slurry, and then the cavity area of the karst cave is filled with the first slurry.

[0075] The karst cave in the semi-filled mode means that there are some void areas inside the karst cave and some non-void areas filled with other materials. There are other materials providing a certain strength in the non-void areas, but the strength may not meet the requirements. Filling the non-void intervals at the bottom of the karst cave with the second slurry can improve the strength of the non-void areas. In the void areas, there is no additional material providing strength. Therefore, filling the void areas of the karst cave with the first slurry can improve the overall strength of the karst cave in the semi-filled mode. Specifically, in the non-void filling area, directly use the mineral waste-based solidifying material second slurry for jet grouting reinforcement treatment. The jet grouting trolley lowers the jet grouting drill rod to the bottom of the filler through the existing borehole and performs rotary jet grouting. Currently, the maximum jet grouting pressure can reach 50-60 MPa. In clay, the jet grouting diameter can reach 2-3 m, and the specific jet grouting diameter size is determined by the bridge pile diameter and the thickness of the hole wall to be reinforced. Lifting while jetting to the height of the top of the filler can complete the jet grouting reinforcement operation. In the non-filled area, directly use the controllable fluid state solid waste filling material first slurry for green filling treatment. Prepare the slurry with the solid waste material on the ground surface, lower the perfusion pipe through the borehole, and then lift the pipe while perfusing until it is lifted more than 0.5 m above the roof of the karst cave.

[0076] Combined with the first aspect, as Figure 4 shown, in some embodiments provided by the present application, the determining the filling mode of the karst cave according to the three-dimensional model information of the karst cave includes:

[0077] S303. If the filling mode of the karst cave is the full-filled mode, then use the second slurry to fill the entire non-void interval of the karst cave.

[0078] The karst cave in the full-filled mode means that the inside of the karst cave is filled with other materials and there are basically no void areas. The strength of these filling materials usually cannot meet the requirements. By using the second slurry to fill the entire non-void interval of the karst cave, the second slurry can be mixed with the original filling materials, thereby improving the overall strength of the karst cave in the full-filled mode. Specifically, directly use the mineral waste-based solidifying material second slurry for jet grouting reinforcement treatment. The jet grouting trolley lowers the jet grouting drill rod to the bottom of the filler through the existing borehole and performs rotary jet grouting. Currently, the maximum jet grouting pressure can reach 50-60 MPa. In clay, the jet grouting diameter can reach 2-3 m, and the specific jet grouting diameter size is determined by the bridge pile diameter and the thickness of the hole wall to be reinforced. Lifting while jetting to the height of the top of the filler can complete the jet grouting reinforcement operation.

[0079] In combination with the first aspect, in some embodiments provided by the present application, the materials of the first slurry include excavated soil, curing agent, stone powder, alkali activator, early strength agent and water. The first slurry including the above materials can make the first slurry form a certain strength after curing, support the bridge pile foundation, improve the strength of the karst cave, and reduce collapse. Among them, the use of excavated soil can avoid material waste and pollution caused by filling and treating karst caves with materials such as concrete, and realize the filling and consumption of solid waste. The excavated soil can be solid waste filling materials such as topsoil, drilling waste mud, and drilling cuttings. The curing agent can cure the slurry, and the curing agent can be at least one of commercially available soil curing agents such as V01, V02, and V03 soil curing agents produced by Nanjing Huanjing New Materials Co., Ltd., and SV-MSS class soil curing agents produced by Jining Haiwei Co., Ltd. The stone powder can improve the strength after the slurry hardens, and the stone powder can be at least one of limestone powder and marble powder materials. The alkali activator can improve the reaction degree of the curing agent, and the alkali activator can be at least one of sodium silicate, calcium hydroxide, and sodium hydroxide materials. The early strength agent can accelerate the hardening of the slurry, and the early strength agent can be at least one of sodium chloride and sodium sulfate materials.

[0080] In combination with the first aspect, in some embodiments provided by the present application, the materials of the second slurry include a curing agent, an alkali activator, an early strength agent and water. The curing agent can be at least one of commercially available soil curing agents such as V01, V02, and V03 soil curing agents produced by Nanjing Huanjing New Materials Co., Ltd., and SV-MSS class soil curing agents produced by Jining Haiwei Co., Ltd. The alkali activator can be at least one of sodium silicate, calcium hydroxide, and sodium hydroxide materials. The early strength agent can be at least one of sodium chloride and sodium sulfate materials. The second slurry including the above materials can make the second slurry penetrate into the karst cave area filled with other materials and cure with other materials to increase the strength.

[0081] It should be noted that the viscosity of the first slurry is generally greater than that of the second slurry, and the solid content of the first slurry is generally greater than that of the second slurry. The ratio of the first slurry and the second slurry can be selected according to the construction site. The fluidity of the first slurry can be 220 - 280 mm. The fluidity of the second slurry can be 260 - 300 mm.

[0082] Using the above materials can also reduce the carbon emissions of treating karst caves. The carbon emissions consist of the following parts: production of raw materials for curing materials, slurry preparation process, and perfusion process. The calculation method is as follows:

[0083] Calculate the carbon emissions x kgCO2e / t during the production of each ton of raw materials, and calculate the raw materials k t of the curing materials required for preparing 1 m 3 of slurry according to the mix ratio;

[0084] During the slurry preparation process, calculate that for every 1 m of stirring 3The power consumption n kWh required by the slurry-related machinery, and the power consumption per 1m of pumping during the pouring process 3 The electricity consumption required for slurry is m kWh, and the average carbon emission per kWh in each province is y kgCO2e / m 3 ;

[0085] Calculate every 1m 3 Carbon emissions from caves z = kx + (m + n) y kgCO2e.

[0086] By comparing the carbon emissions generated by the traditional method and the method described in this patent, the carbon emissions reduced by the comprehensive treatment method of this patent can be obtained. Mainly including: carbon emissions reduced by the disposal of solid waste in caves; carbon emissions generated by the transportation of solid waste such as mud and excavated soil; and carbon emissions generated by the reduction of cement concrete materials. Through comprehensive treatment combining three-dimensional cave detection, green cave treatment, and carbon emission calculation, the location and morphology of caves in complex areas are explored, and a three-dimensional refined cave regional model is established. At the same time, cave treatment and solid waste disposal are realized, and harmless cave treatment is achieved to reduce carbon emissions.

[0087] In combination with the first aspect, in some embodiments provided in the present application, the strength of the first slurry after curing for 7 days is 0.5-3 MPa. The strength of the first slurry after curing for 28 days is 1-5 MPa, and the strength can continue to increase in 1-2 years, thereby improving the support for the bridge pile foundation.

[0088] In combination with the first aspect, in some embodiments provided in the present application, after the cave is filled, the permeability of the filling material after hardening for 7 days is 10 -8 ~10 -9 cm / s. The permeability coefficient of natural sand and silt is 10 -5 ~10 -6 cm / s. The permeability coefficient of the cave after hardening for 7 days after filling is lower than that of natural sand and silt, which can effectively prevent the problems of slurry leakage and filtration loss during the drilling process of bridge pile foundation.

[0089] In summary, by obtaining the three-dimensional model information of the cave and filling the cave according to the filling method and the corresponding filling slurry, the cave can be accurately filled according to the actual shape of the cave, reducing the waste of filling materials and achieving localized and quantitative controllable management. The fluidity of the filling slurry is 220-300mm, which can make the filling slurry flow between the complex gullies inside the cave, realize the filling of the cave, and improve the strength of the filling.

[0090] In the description of this specification, the descriptions with reference to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0091] It should be noted that in this application, relational terms such as "first" and "second" etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, the element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the said element. In this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0092] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for treating karst caves in bridge pile foundations, characterized in that, It includes the following steps: Obtain the three-dimensional model information of the karst cave; Determine the filling method of the karst cave according to the three-dimensional model information of the karst cave; Fill the karst cave with the corresponding filling slurry according to the filling method; Among them, the fluidity of the filling slurry is 220-300mm.

2. The method for treating karst caves in bridge pile foundations according to claim 1, wherein, The method for obtaining the three-dimensional model of the karst cave includes the combined detection of the first detection method, the second detection method and the third detection method, where: The first detection method includes at least one of seismic exploration, electrical exploration and electromagnetic exploration; The second detection method includes the drilling method; The third detection method includes at least one of the tube wave detection method and the cross-hole nuclear magnetic method.

3. The method for treating karst caves in bridge pile foundations according to claim 1, characterized in that, The three-dimensional model information of the karst cave includes at least one of the distribution of the karst cave, the type of the karst cave, the volume of the karst cave and the filling type of the karst cave.

4. The method for treating karst caves in bridge pile foundations according to claim 1, characterized in that, The filling method includes a non-filling method, a semi-filling method and a full-filling method, where: The non-filling method uses the first slurry for filling; The semi-filling method uses the first slurry and the second slurry for filling; The full-filling method uses the second slurry for filling; The first slurry and the second slurry are different.

5. The method for treating karst caves in bridge pile foundations according to claim 4, characterized in that, The determination of the filling method of the karst cave according to the three-dimensional model information of the karst cave includes: If the filling method of the karst cave is the non-filling method, the first slurry is used to fill the entire cavity area of the karst cave.

6. The method for treating karst caves in bridge pile foundations according to claim 4, wherein, The determination of the filling method of the karst cave according to the three-dimensional model information of the karst cave includes: If the filling method of the karst cave is the semi-filling method, the second slurry is used to fill the non-cavity area at the bottom of the karst cave, and then the first slurry is used to fill the cavity area of the karst cave.

7. The method for treating karst caves in bridge pile foundations according to claim 4, characterized in that, The determination of the filling method of the karst cave according to the three-dimensional model information of the karst cave includes: If the filling method of the karst cave is the full-filling method, the second slurry is used to fill the entire non-cavity area of the karst cave.

8. The method for treating karst caves in bridge pile foundations according to claim 4, characterized in that: The materials of the first slurry include excavated soil, curing agent, stone powder, alkali activator, early strength agent and water; and / or, The materials of the second slurry include curing agent, alkali activator, early strength agent and water.

9. The method for treating karst caves in bridge pile foundations according to claim 8, characterized in that, The strength of the first slurry after hardening for 7 days is 0.5-3MPa.

10. The method for treating karst caves in bridge pile foundations as described in claim 1, characterized in that, After the karst cave is filled, the permeability of the filler is 10 -8 ~10 -9 cm / s after 7 days of hardening.

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