A phased dynamic estimation method for karst grouting quantity

Abstract

This invention discloses a phased dynamic estimation method for karst grouting volume, comprising the following steps: obtaining the area of ​​the treatment zone; determining the grouting section length and average linear solubility of the boreholes based on survey data and project type; determining the grouting expansion coefficient, karst planar distribution coefficient, filling rate, grout loss coefficient, and grouting hole density correction coefficient; and calculating the grouting volume using a zone summation formula. This invention employs preliminary estimation, field test calibration, and construction dynamic correction according to different design stages. The estimated value gradually converges to the actual value as data becomes more abundant. It is applicable to various karst grouting projects such as natural foundations, pile foundations, and tunnels, achieving full life-cycle control of grouting volume. The estimation is accurate, the parameters are clear, and the operation is simple.

Description

Technical Field

[0001] This invention relates to the fields of geotechnical engineering and grouting engineering, and in particular to a phased dynamic estimation method for karst grouting volume. Background Technology

[0002] When constructing engineering projects in karst areas, adverse karst geological conditions can seriously threaten project safety, often necessitating grouting to fill karst cavities, seal seepage channels, and improve foundation bearing capacity and surrounding rock stability. Accurate estimation of the grouting volume directly impacts project cost, material procurement, construction organization, and schedule planning, making it a crucial step in the engineering design phase. However, due to the highly concealed, non-uniform, and unpredictable nature of karst development, accurate estimation of the grouting volume has always been a technical challenge in geotechnical engineering.

[0003] Currently, there is no unified and reliable calculation method for estimating karst grouting volume, either domestically or internationally. Existing technologies mainly include the following: (1) Empirical analogy based on similar projects: The volume of grouting is estimated by multiplying the unit grouting volume of similar projects (such as the empirical value of grouting volume per cubic meter of karst) by the treatment volume of this project. This method relies on the statistical data of existing projects, but the degree of karst development, filling type, connectivity, groundwater conditions and other factors vary significantly from site to site. Simple analogy often leads to large errors and cannot reflect the specific geological characteristics of this site.

[0004] (2) Coefficient calibration method based on field grouting test: The empirical value of the unit grouting volume is obtained by conducting field grouting tests on a limited scale, and then multiplied by the treatment range to obtain the total grouting volume. This method has extremely high requirements for the representativeness of the test area and lacks an independent correction mechanism for factors such as differences in filling type and unevenness of planar distribution. When the karst development of the site is uneven, the extrapolation error is significant.

[0005] (3) Method for determining grouting volume based on fractal theory: The distribution law of karst caves is described by fractal parameters, the volume of karst caves is determined according to the fractal parameters, and the grouting volume coefficient is determined by combining the on-site grouting volume. This method has a complicated calculation process and fails to effectively distinguish the contribution of different factors such as filling rate, planar distribution, and grout loss to the grouting volume.

[0006] (4) Prediction method based on multi-source data fusion: This method relies on sensors to collect data such as rock stratum dissolution rate and porosity in real time, and then makes real-time corrections based on ambient temperature and humidity. This method requires the deployment of a large number of sensors and a real-time data acquisition system, which is costly to implement. It is mainly used for real-time prediction during construction and is not suitable for estimating grouting volume before construction.

[0007] The aforementioned existing technologies all share the following common defects: (1) The planar distribution and vertical development of karst were not effectively decoupled, resulting in insufficient accuracy in volume estimation; (2) The physical relationship between the value of the filling rate and the degree of filling of the karst cave is unclear; (3) The influence of the grouting hole spacing on the grouting volume is not considered, and the superposition effect of grout caused by different hole densities is ignored; grouting pressure is also an important factor affecting the grout diffusion range and loss degree, and the existing methods lack systematic consideration of its influence.

[0008] (4) There is a lack of a graded estimation system covering the entire life cycle from feasibility study to construction stage. It is impossible to make a quick estimate when there is insufficient survey data, and it is impossible to gradually improve the accuracy after obtaining more detailed data. Furthermore, there is no dynamic correction mechanism based on measured data during the construction process.

[0009] Therefore, developing a method for estimating karst grouting volume that can comprehensively consider karst volume, filling rate, planar distribution, grout loss, and pore density, and can be applied in stages according to project type and design stage, has significant engineering practical value and broad application prospects. Summary of the Invention

[0010] One of the objectives of this invention is to overcome the technical defects of existing karst grouting volume estimation methods, and to solve the problems of inaccurate karst volume estimation, neglect of grouting hole density effect, incompatibility of grouting depth with different engineering types, and lack of phased applicability in existing methods.

[0011] The second objective of this invention is to provide a scientific, practical, and adaptable method for dynamic estimation of karst grouting volume in stages, covering multiple types of engineering projects and the entire life cycle, thereby improving the accuracy of estimation and the practicality of engineering applications.

[0012] In a first aspect of the present invention, a method for phased dynamic estimation of karst grouting volume is provided, comprising the following steps: S1. Obtain the processing area area of ​​the site. The length of the grouting section was determined based on the karst exploration data after the site survey. L and average linear melting rate of borehole ; S2. Determine the following parameters: (a) Grouting range expansion coefficient , wherein The value range is 1.05 to 1.15; (b) Karst planar distribution coefficient , wherein Determined by the ratio of the total horizontal projected area of ​​the karst caves to the area of ​​the treatment area; (c) Karst volumetric grouting filling rate This is determined by the type of karst cave filling. The range of values ​​for , wherein when the karst cave is a cavity type, the The value range is 0.60 to 0.85; when the karst cave is semi-filled, the... The value range is 0.30 to 0.60; when the karst cave is fully filled, the value of... The value range is 0.10 to 0.30; (d) Slurry loss coefficient , wherein The value range is 0.05 to 0.45; (e) Grouting hole density correction factor , wherein Calculated using the following formula: in, Preset reference hole spacing, This refers to the actual spacing between grouting holes. It is an empirical index with a value range of 0.3 to 0.8; S3. Calculate the karst grouting volume : (i) When the karst development depth of the site is relatively uniform, a single zone is adopted, and the karst grouting volume is calculated according to the following formula. : in, To process the area, For the length of the grouting section, For the average linear yield of boreholes, For karst planar distribution coefficient, For karst volume grouting filling rate, For slurry loss coefficient, This is the correction factor for the density of the grouting holes; (ii) When the depth of karst development in the site varies greatly, the site shall be divided into several zones, the zones shall be numbered, and the length of the grouting section for each zone shall be determined. The karst grouting volume is calculated according to the following formula. : in, For partition numbering, For the first The processing area of ​​each partition. For the first The length of the grouting section in each zone, For the first Average linear melt rate of boreholes in each zone For the first Karst plane distribution coefficient of each zone, For the first The karst volumetric grouting filling rate of each zone For the first Slurry loss coefficient of each zone, For the first The grouting hole density correction factor for each zone.

[0013] In another preferred embodiment, the borehole average linear flux The result is obtained by calculating using the following formula; .

[0014] In another preferred embodiment, the soluble rock strata are limestone, dolomite, or other rock strata capable of developing karst.

[0015] In another preferred embodiment, the overburden and non-soluble rock interlayers have been removed during the total depth of the hole through the soluble rock.

[0016] In another preferred embodiment, the karst volumetric grouting filling rate The values ​​are determined based on the type of karst cave filling and existing engineering experience.

[0017] In another preferred embodiment, when the site is an important engineering project or a loose fill area, the grouting range expansion coefficient is... The value range is 1.10 to 1.15, with 1.10 being preferred.

[0018] In another preferred embodiment, the karst planar distribution coefficient It is obtained through the following steps: N1. The total horizontal projected area of ​​the karst cave is calculated by geophysical methods, wherein the geophysical methods are selected from the following group: high-density electrical resistivity tomography, cross-hole seismic CT, cross-hole radar, or a combination thereof; N2. Divide the sum of the horizontal projected areas of the karst caves obtained in step N1 by the total area of ​​the treated area. The karst planar distribution coefficient is obtained. ; In cases where karst exploration is in the feasibility study or preliminary design stage and geophysical data is lacking, the borehole encounter rate is calculated. And multiply by an empirical correction factor After adjustment, it replaces the above. The borehole encounter rate The result is obtained by the following formula: in, To determine the number of boreholes in the cave, The total number of boreholes; the empirical correction factor. The range of values ​​is determined by the size and distribution characteristics of the karst caves. Specifically, when the karst caves are large and their distribution is continuous... The value range is 1.0~1.2; when the cave is of medium size and the caves are relatively evenly distributed, The value range is 1.2 to 1.3; when the caves are small in scale, isolated in distribution, and appear as points, The value range is 1.3 to 1.5.

[0019] In another preferred embodiment, the karst planar distribution coefficient It reflects the extent to which the caves cover the surface.

[0020] In another preferred embodiment, the borehole encounter rate It reflects the probability of encountering a cave at a given point during drilling.

[0021] In another preferred embodiment, the empirical correction coefficient The principle for determining the value is as follows: when the horizontal projected area of ​​the karst cave is large, the borehole is more likely to hit the cave, and the cave encounter rate can better reflect the planar distribution. Take a smaller value (close to 1.0); when the caves are small and isolated, the probability of borehole hit is low, and the cave encounter rate will be significantly lower than the actual area ratio. Take the larger value (close to 1.5).

[0022] In another preferred embodiment, the large-scale, continuously distributed caves include beaded or layered large caves.

[0023] In another preferred embodiment, when geophysical data is available for karst exploration, the karst planar distribution coefficient obtained through steps N1 and N2 is used. .

[0024] In another preferred embodiment, when the karst exploration is in the feasibility study or preliminary design stage and geophysical data is lacking, the calculated karst grouting volume is used for investment estimates and scheme comparison, wherein the karst grouting volume is allowed to have an error of ±50%.

[0025] In another preferred embodiment, the length of the grouting section is... Determined in the following ways: When the site is a natural foundation, the length of the grouting section is... The grouting section extends from the base surface to the designed treatment depth, where the designed treatment depth is 5–10 m below the base or to intact bedrock, or the length of the grouting section depends on the depth of the karst cave distribution. It extends from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than the depth of the foundation compression layer. When the site is a pile foundation project, the length of the grouting section is... The depth ranges from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than 3 to 5 m below the pile tip. When the site is a tunnel project, the length of the grouting section is... The thickness of the radial reinforcement ring outside the tunnel excavation outline, or the length of the grouting section. The distribution range of karst caves was determined based on advanced geological forecasts.

[0026] In another preferred embodiment, when the tunnel grouting is for reinforcing the surrounding rock of the tunnel, the length of the grouting section is... The thickness of the radial reinforcement ring outside the tunnel excavation outline.

[0027] In another preferred embodiment, the thickness of the radial reinforcement ring outside the tunnel excavation outline is 3 to 8 m.

[0028] In another preferred embodiment, when the tunnel project is located in a water-rich karst development area, the thickness is 5 to 8 m.

[0029] In another preferred embodiment, when the tunnel grouting is for treating karst caves below the floor slab, the length of the grouting section is... The distribution range of karst caves was determined based on advanced geological forecasts.

[0030] In another preferred embodiment, when advanced geological forecasting reveals the existence of hidden karst caves below the tunnel floor that pose a threat to structural safety, the length of the grouting section is... It is the vertical distance from the tunnel floor to the bottom of the karst cave, which is no less than 2 meters below the floor.

[0031] In another preferred embodiment, the length of the grouting section is... It is determined by the actual depth of the cave.

[0032] In another preferred embodiment, the method further includes an on-site grouting test calibration step, which includes the following steps: Y1. Select a test block within the treatment area, wherein the area of ​​the test block is not less than 200 m². 2 ; Y2. Obtain the true karst development volume through geophysical methods. Grouting was then carried out and the actual grouting volume was recorded. Calculate the overall coefficient on site The geophysical methods described herein are selected from the group consisting of: high-density electrical resistivity tomography, trans-pore seismic CT, trans-pore radar, or combinations thereof; The result is obtained by the following formula: Y3, will and A comparison is made, and when the deviation between the two exceeds 30%, then... or Adjustments will be made.

[0033] In another preferred embodiment, the grouting is performed according to design parameters, which include at least the grouting hole spacing, grouting pressure, and grout mix ratio.

[0034] In another preferred embodiment, the design parameters are dynamically adjusted based on geological conditions, grouting test results, and design requirements.

[0035] In another preferred embodiment, the permissible error of the karst grouting volume calculated by the method including the on-site grouting test calibration step is ±30%.

[0036] In another preferred embodiment, the method further includes a dynamic correction step, which includes the steps of: Z1. Divide the holes for grouting construction into first-order holes, second-order holes and third-order holes, and divide the hole sequence into multiple grouting units; Z2. After each grouting unit is completed, calculate the actual grouting volume per unit volume. , wherein The following formula is used to calculate: ; Simultaneously, the design comprehensive coefficient is calculated. , wherein It is obtained by calculation using the following formula; and Design integration coefficient Compare; when and When the relative deviation exceeds 20%, the design comprehensive coefficient of the subsequent grouting unit shall be corrected by moving average according to the following formula: Among them, when the project site is of medium to large size and the total number of grouting units is not less than 20, The value is 5 to 10; when the site is small and the total number of grouting units is less than 10, This represents the total number of all constructed units.

[0037] In another preferred embodiment, the dynamic correction step is performed after the field grouting test calibration step.

[0038] In another preferred embodiment, the design integration coefficient This is the baseline value for the estimated grouting volume per unit volume of karst, obtained from the design phase of the construction drawings.

[0039] In another preferred embodiment, the spacing between the sequential holes is 6 to 8 m.

[0040] In another preferred embodiment, the spacing between the two sequential holes is 4 to 5 m.

[0041] In another preferred embodiment, the three-stage holes are encryption holes.

[0042] In another preferred embodiment, the encryption hole is an interpolation encryption in the middle of the grid formed by the previous sequential holes.

[0043] In another preferred embodiment, the densification of the holes further reduces the hole spacing and densifies the hole mesh. In another preferred embodiment, 8-12 holes constitute one grouting unit.

[0044] In another preferred embodiment, a natural block is a grouting unit.

[0045] In another preferred embodiment, the permissible error for the karst grouting volume calculated by the method including the dynamic correction step is ±10%.

[0046] In another preferred embodiment, when calculating the grouting hole density correction factor... At that time, the preset reference hole spacing The value range is 1.0 to 3.0 m. The experience index The range of values ​​is determined based on the degree of karst development, among which, When the karst site is an isolated cave site, the empirical index The value range is 0.3 to 0.4; When the karst site is a typical karst site, the empirical index The value range is 0.4 to 0.6; When the karst site is a highly developed and interconnected site, the empirical index... The value range is 0.6 to 0.8.

[0047] In another preferred embodiment, the slurry loss coefficient The value range is determined by the degree of fracture development, groundwater flow conditions, and grouting pressure. When the fissures are not well-developed, the groundwater flow conditions are static, and / or the grouting pressure is low, the The value range is 0.05 to 0.15; When the fissure is moderately developed, the The value range is 0.15 to 0.25; When the fissures are dense, the groundwater flow conditions are dynamic, and / or the grouting pressure is high, the following The value range is 0.25 to 0.45.

[0048] In another preferred embodiment, the slurry loss coefficient It reflects the additional grouting volume caused by the grout seeping into the micro-fractures and pores of the rock mass and flowing outward along the connecting channels during the grouting process.

[0049] In another preferred embodiment, the low pressure is 0.2 to 0.5 MPa.

[0050] In another preferred embodiment, the high pressure is >1.0 MPa.

[0051] In another preferred embodiment, the length of the grouting section is... Determine using the following steps: X1. Based on the depth of the top and bottom plates of the karst caves revealed by the boreholes, draw karst development contour maps and divide the site into several karst development zones. X2. When the site is a natural foundation, the length of the grouting section. For the first Within each zone, the grouting section extends from the foundation bottom surface to the designed treatment depth, where the designed treatment depth is 5–10 m below the foundation or to intact bedrock, or, depending on the depth of the karst cave distribution, the length of the grouting section. It extends from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than the depth of the foundation compression layer. When the site is a pile foundation project, the length of the grouting section is... For the first Within each zone, the shallowest cave ceiling is 2m above the top of the shallowest cave ceiling and the deepest cave ceiling is 2m below the bottom of the deepest cave ceiling, and the depth is not less than 3 to 5m below the pile tip. When the site is a tunnel project, the length of the grouting section is... For the first The thickness of the radial reinforcement ring outside the tunnel excavation outline within each zone, or the thickness of the karst cave distribution range determined by advanced geological forecasting.

[0052] In another preferred embodiment, when the tunnel grouting is for reinforcing the surrounding rock of the tunnel, the length of the grouting section is... For the first Thickness of the radial reinforcement ring outside the tunnel excavation outline within each zone.

[0053] In another preferred embodiment, the thickness of the radial reinforcement ring outside the tunnel excavation outline is 3 to 8 m.

[0054] In another preferred embodiment, when the tunnel project is located in a water-rich karst development area, the thickness is 5 to 8 m.

[0055] In another preferred embodiment, when the tunnel grouting is for treating karst caves below the floor slab, the length of the grouting section is... The distribution range of karst caves was determined based on advanced geological forecasts.

[0056] In another preferred embodiment, when advanced geological forecasting reveals the existence of hidden karst caves below the tunnel floor that pose a threat to structural safety, the length of the grouting section is... For the first The vertical distance from the tunnel floor to the bottom of the karst cave within each zone shall be no less than 2 meters.

[0057] In another preferred embodiment, the length of the grouting section is... By the The actual depth of the caves within each zone is determined by their distribution.

[0058] In another preferred embodiment, the karst volumetric grouting filling rate The range of values ​​is determined based on the type of karst cave filling and existing engineering experience. When the type of karst cave filling is a hollow karst cave, the The value range is 0.60 to 0.85; When the cave filling type is a semi-filled cave, the The value range is 0.30 to 0.60; When the cave filling type is a fully filled cave, the The value range is 0.10 to 0.30.

[0059] In another preferred embodiment, the karst volumetric grouting filling rate It reflects the proportion of the void volume that needs to be injected with grout to the total volume of the cavern.

[0060] In another preferred embodiment, the karst volumetric grouting filling rate It is inversely proportional to the degree of filling of the cave.

[0061] In another preferred embodiment, the hollow cave is a cave without filling material and with an intact cavity.

[0062] In another preferred embodiment, the semi-filled karst cave is partially filled with clay and gravel, with a remaining porosity of 30% to 70%.

[0063] In another preferred embodiment, the fully filled cavern is filled with a dense material, with only cracks or a few pores present.

[0064] In another preferred embodiment, the method further includes a boundary locking step: M1, for karst planar distribution coefficient In the treated area, first construct sealing holes along the boundary of the treated area to form a grouting curtain, and then construct the internal holes.

[0065] In another preferred embodiment, the boundary locking step reduces grout leakage and significantly reduces grouting losses in internal holes.

[0066] A second aspect of the present invention provides a method for cost estimation and project management in karst grouting engineering, comprising the following steps: In karst grouting projects, the method described in the first aspect of this invention is used to calculate the karst grouting volume for project cost and project management.

[0067] In another preferred embodiment, the karst grouting project is selected from the group consisting of: natural foundation karst grouting project, pile foundation karst grouting project, and tunnel karst grouting project.

[0068] In another preferred embodiment, the project cost and project management are selected from the group consisting of: preparation of karst grouting bill of quantities, investment estimate, material procurement or construction management.

[0069] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0070] Figure 1 This is a flowchart illustrating the overall process of the phased dynamic estimation method for karst grouting volume according to the present invention. Figure 2 This is a flowchart illustrating the dynamic correction during the construction phase of this invention. Detailed Implementation

[0071] Through extensive and in-depth research, the inventors have discovered for the first time a phased dynamic estimation method for karst grouting volume, comprising the steps of: obtaining the area of ​​the treatment zone. The length of the grouting section is determined based on the survey data and the type of project. and average linear melting rate of borehole Determine the grouting expansion coefficient. Karst planar distribution coefficient Filling rate Slurry loss coefficient and grouting hole density correction factor Using the partition summation formula Calculating grouting volume. This invention employs preliminary estimation, on-site test calibration, and construction dynamic correction according to different design stages. The estimated value gradually converges to the actual value as data becomes more abundant. It is applicable to various karst grouting projects such as natural foundations, pile foundations, and tunnels, achieving full life-cycle control of grouting volume. The estimation is accurate, the parameters are clear, and the operation is simple. This invention was completed based on these principles.

[0072] the term Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0073] As used herein, the terms “comprising,” “including,” and “containing” are used interchangeably and include not only closed definitions but also semi-closed and open definitions. In other words, the terms include “consisting of” and “substantially consisting of”.

[0074] As used in this article, the term "densification and hole filling" refers to the arrangement of holes according to the principle of sequential densification and interpolation densification. That is, densification is interpolated in the middle of the grid formed by the holes in the previous sequence to further reduce the hole spacing and densify the hole grid. The densification and hole filling is used to supplement the grouting of areas or important parts that still have defects after the previous grouting, so as to achieve the purpose of precise reinforcement of local areas and elimination of grouting dead corners.

[0075] As used in this article, the term "natural block" refers to an area that is naturally divided based on the actual conditions of the engineering site, geological conditions (such as the degree of karst development), engineering structure (such as independent buildings or foundations), or construction organization, which is convenient for independent grouting construction and effect statistics. It is a descriptive and flexible engineering concept.

[0076] Embodiments of the present invention The first aspect of this invention provides a method for dynamically estimating the volume of karst grouting in stages, comprising the following steps: Step 1: Obtain the area of ​​the processing region The length of the grouting section was determined based on karst exploration data. L and average linear melting rate of borehole ; When the depth of karst development varies significantly within the site, the site is divided into several zones, and the length of the grouting section in each zone is determined accordingly. .

[0077] Step 2, determine the following parameters: (a) Grouting range expansion coefficient The value ranges from 1.05 to 1.15. (b) Karst planar distribution coefficient It is determined based on the ratio of the total horizontal projected area of ​​the karst caves to the area of ​​the treatment area; (c) Karst volumetric grouting filling rate The values ​​are determined based on the type of karst cave filling and existing engineering experience: 0.60–0.85 for hollow caves, 0.30–0.60 for semi-filled caves, and 0.10–0.30 for fully filled caves. (d) Slurry loss coefficient The value ranges from 0.05 to 0.45. (e) Grouting hole density correction factor ,in Preset reference hole spacing, This refers to the actual spacing between grouting holes. It is an empirical index with a value range of 0.3 to 0.8.

[0078] Step 3: Calculate the karst grouting volume using the following formula. (unit: m) 3 ): When the karst development depth is relatively uniform, a single zone can be adopted, and the formula can be simplified to: In one specific embodiment, the length of the grouting section Determine as follows: (1) For natural foundations: take the depth from below the foundation bottom to the design treatment depth (5-10 m below the base or to the intact bedrock), or take the depth from 2 m above the top of the shallowest karst cave to 2 m below the bottom of the deepest karst cave, and not less than the depth of the foundation compression layer; (2) For pile foundation engineering: the distance is from 2 m above the top of the shallowest karst cave to 2 m below the bottom of the deepest karst cave, and not less than 3 to 5 m below the pile tip; (3) For tunnel engineering: take the karst treatment depth within a certain range outside the tunnel excavation outline, and determine the distribution range of karst caves based on the advanced geological forecast.

[0079] In a specific implementation, when the purpose of grouting in a tunnel project is to reinforce the surrounding rock of the tunnel, the length of the grouting section is... The thickness of the radial reinforcement ring outside the tunnel excavation outline is generally 3 to 8 meters. The specific value is determined according to the project type and hydrogeological conditions. Generally, it is 3 to 5 meters for karst tunnels and 5 to 8 meters for water-rich karst development areas. It can be appropriately increased for important tunnels or complex geological conditions.

[0080] In a specific embodiment, when the purpose of grouting in a tunnel project is to treat karst caves below the floor slab, the length of the grouting section is... Based on the distribution range of karst caves determined by advanced geological forecasting, when advanced geological forecasting reveals the existence of hidden karst caves below the tunnel floor that pose a threat to structural safety... L The vertical distance from the tunnel floor to the bottom of the karst cave is no less than 2 meters, and is determined by the actual depth of the karst cave, with no fixed upper limit.

[0081] In a specific implementation, when the method is applied to the feasibility study or preliminary design stage, each parameter is estimated using the median or conservative value within an empirical range, wherein the karst plane distribution coefficient... The borehole encounter rate can be used. approximate, To determine the number of boreholes in the cave, The total number of boreholes is calculated by multiplying the average size of the karst cave by an empirical correction factor. Adjustments were made from 1.0 to 1.5.

[0082] In one specific embodiment, when the method is applied to the construction drawing design stage, it further includes an on-site grouting test calibration step: selecting an area of ​​not less than 200 m² in the treatment area. 2 In the test block, geophysical methods (including at least one of high-density electrical resistivity tomography, cross-hole seismic CT, and cross-hole radar) were used to obtain the actual karst development volume. Grouting was performed according to the design parameters, and the actual grouting volume was recorded. Calculate the overall coefficient on site ,Will and If the deviation exceeds 30%, adjust accordingly. or .

[0083] In a specific embodiment, when the method is applied to the construction phase, it further includes a dynamic correction step: dividing the grouting construction into first-order holes, second-order holes, and third-order holes; calculating the actual grouting volume per unit volume after each grouting unit is completed. ;Will Design integration coefficient In comparison, the stated This is the baseline value for the estimated grouting volume per unit volume of karst obtained from the construction drawing design stage; if the relative deviation exceeds 20%, the subsequent design coefficient is corrected by the following sliding average formula: For medium to large-scale engineering sites (the total number of grouting units shall not be less than 20). Take 5-10; when the site is small and the total number of grouting units is less than 10, The total number of completed units can be retrieved.

[0084] In a specific embodiment, the karst planar distribution coefficient The determination method is as follows: the total horizontal projected area of ​​the karst cave is directly calculated by geophysical methods (including at least one of high-density electrical resistivity tomography, cross-hole seismic CT, and cross-hole radar), and then divided by the total area of ​​the processed area. .

[0085] In one specific embodiment, the grouting hole density correction coefficient In the middle, the spacing between reference holes m, experience index The value is determined based on the degree of karst development: 0.3 to 0.4 for isolated cave sites, 0.4 to 0.6 for general karst sites, and 0.6 to 0.8 for sites with strong development and high connectivity.

[0086] In one specific embodiment, the slurry loss coefficient The values ​​are determined based on the degree of fissure development, groundwater flow conditions, and grouting pressure: 0.05–0.15 for undeveloped fissures, static water conditions, and low-pressure grouting (0.2–0.5 MPa); 0.15–0.25 for moderately developed fissures; and 0.25–0.45 for dense fissures, dynamic water conditions, or high-pressure grouting (>1.0 MPa).

[0087] In a specific implementation, when the depth of karst development within the site varies significantly, the length of the grouting section... The following zoning is used to determine the karst development zones: Based on the depths of the top and bottom slabs of the karst caves revealed by boreholes, draw karst development contour maps to divide the site into several karst development zones. For natural foundations, within each zone, the depth is taken from below the foundation bottom to the design treatment depth (5–10 m below the base or to intact bedrock), or based on the depth of the karst cave distribution, from 2 m above the shallowest karst cave top slab to 2 m below the deepest karst cave bottom slab, and not less than the depth of the foundation compression layer. For pile foundation projects, within each zone, the depth is taken from 2 m above the shallowest karst cave top slab to 2 m below the deepest karst cave bottom slab, and not less than 3–5 m below the pile tip. For tunnel projects, within each zone, the karst treatment depth is taken within a certain range outside the tunnel excavation outline, determined based on the karst cave distribution range determined by advanced geological forecasting.

[0088] In a specific implementation, when the purpose of grouting in a tunnel project is to reinforce the surrounding rock of the tunnel, the length of the grouting section is... According to the first The thickness of the radial reinforcement ring outside the tunnel excavation outline of each zone is generally 3 to 8 meters. The specific value is determined according to the project type and hydrogeological conditions. Generally, it is 3 to 5 meters for karst tunnels and 5 to 8 meters for water-rich karst development areas. It can be appropriately increased for important tunnels or complex geological conditions.

[0089] In a specific embodiment, when the purpose of grouting in a tunnel project is to treat karst caves below the floor slab, the length of the grouting section is... According to the The distribution range of karst caves determined by advanced geological forecasting for each zone has been determined. When advanced geological forecasting reveals the existence of hidden karst caves below the tunnel floor that pose a threat to structural safety, Take the first Within each zone, the vertical distance from the tunnel floor to the bottom of the karst cave is no less than 2 meters, determined by the actual depth of the karst cave, with no fixed upper limit.

[0090] In one specific implementation, boundary locking measures are also included: for the karst plane distribution coefficient In the treated area, sealing holes are first constructed along the boundary of the treatment area to form a grouting curtain, and then internal holes are constructed to reduce grout loss across the boundary and significantly reduce grouting loss in the internal holes.

[0091] In one specific embodiment, the method is applicable to the preparation of bill of quantities, investment estimates, material procurement, or construction management for various karst grouting projects such as natural foundations, pile foundations, and tunnels.

[0092] Technical solution of the present invention To achieve the above objectives, the present invention adopts the following technical solution: A phased dynamic estimation method for karst grouting volume includes the following steps: Step 1: Obtain basic geometric parameters Get the processing area area (unit: m) 2 The length of the grouting section was determined based on karst exploration data. L and average linear melting rate of borehole .in Soluble rock strata refer to rock strata such as limestone and dolomite that may develop karst. Overburden and non-soluble rock interlayers have been removed during the drilling process.

[0093] Grouting section length The method for determining the area varies depending on the type of project, but the unified principle is to cover the karst area that needs to be treated. (1) For natural foundations: take the depth from below the foundation bottom to the design treatment depth (5-10 m below the base or to the intact bedrock), or take the depth from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and not less than the depth of the foundation compression layer.

[0094] (2) For pile foundation engineering: the distance is from 2 m above the top plate of the shallowest karst cave to 2 m below the bottom plate of the deepest karst cave, and not less than 3 to 5 m below the pile tip.

[0095] (3) For tunnel engineering: The karst treatment depth is determined within a certain range outside the tunnel excavation outline, based on the distribution range of karst caves determined by advanced geological forecasting. Wherein, when the purpose of grouting in tunnel engineering is to reinforce the surrounding rock of the tunnel, the length of the grouting section is... The thickness of the radial reinforcement ring outside the tunnel excavation outline is generally 3–8 m, with the specific value determined based on the project type and hydrogeological conditions. For karst tunnels, it is generally 3–5 m; for water-rich karst areas, it is 5–8 m; and for important tunnels or complex geological conditions, it can be appropriately increased. When the purpose of grouting in a tunnel project is to treat karst caves below the floor slab, the length of the grouting section is... Based on the distribution range of karst caves determined by advanced geological forecasting, when advanced geological forecasting reveals the existence of hidden karst caves below the tunnel floor that pose a threat to structural safety... L The vertical distance from the tunnel floor to the bottom of the karst cave should be no less than 2 meters, determined by the actual depth of the karst cave, with no fixed upper limit. When the depth of karst development varies significantly within the site, a karst development contour map is drawn based on the depths of the cave's top and bottom slabs revealed by boreholes. This divides the site into several zones, and the length of the grouting section for each zone is determined accordingly. .

[0096] Step 2: Determine the influencing parameters (1) Grouting range expansion coefficient Considering the effect of the grouting range exceeding the boundary of the treatment area, it is generally taken as 1.05 to 1.10. For important projects or loose fill areas, it is taken as 1.10 to 1.15, and 1.10 is recommended.

[0097] (2) Karst planar distribution coefficient This reflects the proportion of the total projected area of ​​the karst caves on the horizontal plane to the total area of ​​the treated area. It is determined by directly calculating the total horizontal projected area of ​​the karst caves using geophysical methods (including at least one of high-density electrical resistivity tomography, cross-hole seismic CT, and cross-hole radar), and then dividing this total projected area by the total area of ​​the treated area. .

[0098] When geophysical data is lacking during the feasibility study or preliminary design stage, the borehole encounter rate can be used. To approximate, where To determine the number of boreholes in the cave, The total number of boreholes is calculated by multiplying the average size of the karst cave by an empirical correction factor. Adjustments were made from 1.0 to 1.5.

[0099] Correction coefficient The principle for determining the value is: borehole encounter rate. This reflects the probability of encountering a karst cave at a specific point in the borehole, while the karst planar distribution coefficient... This reflects the extent to which caves cover the surface. When the horizontal projected area of ​​a cave is large, it is easier to hit the cave with a drill. The cave encounter rate itself can already reflect the planar distribution quite well. Take the smaller value (close to 1.0); when the caves are small and isolated, the probability of borehole hit is low, and the cave encounter rate will be significantly lower than the actual area ratio. Take the larger value (closest to 1.5). The specific value can be determined based on the following principles: For large-scale, continuously distributed caves (such as beaded or layered large caves), take... The caves are of medium size and relatively evenly distributed. The caves are small in scale, isolated in distribution, and appear as scattered points. .

[0100] The above values ​​can be verified and adjusted by comparing them with the horizontal projected areas of karst caves revealed by a limited number of geophysical profiles or boreholes. When possible, direct measurement using geophysical methods should still be given priority. .

[0101] (3) Karst volumetric grouting filling rate This parameter reflects the proportion of the void volume requiring grout injection to the total volume of the karst cave. It is inversely proportional to the degree of karst cave filling and is determined based on the type of karst cave filling and existing engineering experience, as follows: ① Hollow type (no filling material, complete cavity): 0.60~0.85; ② Semi-filled type (partially filled with clay and gravel, with a remaining porosity of 30% to 70%): 0.30 to 0.60; ③ Fully filled type (the filling material is dense, with only cracks or a small number of pores): 0.10~0.30.

[0102] (4) Slurry loss coefficient This reflects the additional grouting volume caused by grout seepage into micro-fractures and pores of the rock mass and outward loss along connecting channels during the grouting process. Values ​​are determined based on the degree of fracture development, groundwater flow conditions, and grouting pressure: 0.05–0.15 for poorly developed fractures, static water conditions, and low-pressure grouting (0.2–0.5 MPa); 0.15–0.25 for moderately developed fractures; and 0.25–0.45 for densely populated fractures, dynamic water conditions, or high-pressure grouting (>1.0 MPa).

[0103] (5) Grouting hole density correction factor The following formula reflects the impact of the difference between the actual grouting hole spacing and the reference spacing on the grouting volume: in, The preset reference hole spacing is set to 2.0m (recommended). This represents the actual spacing between grouting holes (in meters). This is an experience index. The value is determined based on the degree of karst development: 0.3 to 0.4 for isolated cave sites, 0.4 to 0.6 for general karst sites, and 0.6 to 0.8 for sites with strong development and high connectivity.

[0104] Step 3: Calculate the grouting volume Calculate the karst grouting volume using the following formula (unit: m) 3 ): in, For partition numbering, For the first The area of ​​each partition , , , , , These are the corresponding parameters for that partition.

[0105] When the karst development depth is relatively uniform, a single zone can be adopted, and the formula can be simplified to: Step 4: Phased Dynamic Application Strategy The method of this invention can be dynamically adjusted by using differentiated parameter values ​​and supplementary steps according to different engineering design stages. (1) Feasibility study / preliminary design stage: Rapid estimation is performed using the median or conservative value within the empirical range. Among these, the karst planar distribution coefficient... The borehole encounter rate can be used. Approximate, and based on the average size of the cave multiplied by an empirical correction factor. (1.0~1.5). Mainly used for investment estimates and scheme comparison, with an allowable error of ±50%.

[0106] (2) Construction drawing design stage: Based on step two, add the on-site grouting test calibration step: Select an area of ​​not less than 200 in the treatment area. In the test block, geophysical methods (such as high-density electrical resistivity tomography, cross-hole seismic CT, and cross-hole radar) were used to obtain the actual karst development volume. Grouting was performed according to the design parameters, and the actual grouting volume was recorded. Calculate the overall coefficient on site ,Will and If the deviation exceeds 30%, adjust accordingly. or This makes the estimation more accurate, and an error of ±30% is allowed at this stage.

[0107] (3) Construction stage: After step three, a dynamic correction step is added, dividing the grouting construction into first-order holes (spacing 6-8 m), second-order holes (spacing 4-5 m), and third-order holes (densification and supplementary holes); after each grouting unit is completed (such as 10 holes or a natural block), the actual unit volume grouting volume of the unit is calculated. ;Will Design integration coefficient In comparison, the stated This is the baseline value for the estimated grouting volume per unit volume of karst obtained from the construction drawing design stage; if the relative deviation exceeds 20%, the design comprehensive coefficient of subsequent grouting units will be corrected by moving average. For medium to large-scale engineering sites (the total number of grouting units shall not be less than 20), A value of 5 to 10 is used when the site is small and the total number of grouting units is less than 10. The total number of completed units can be obtained. An error within ±10% is achievable at this stage.

[0108] In addition, regarding the karst planar distribution coefficient In certain areas, boundary locking measures can be implemented during the construction phase: first, seal the edges along the boundary of the treatment area to form a grouting curtain, and then construct the internal holes to reduce grout loss across the boundary and significantly reduce grouting losses in the internal holes.

[0109] Beneficial effects of the invention Compared with the prior art, the present invention has the following beneficial effects: (1) More scientific volume estimation: by introducing the karst plane distribution coefficient The degree of karst development in the vertical direction (linear karst rate) ) and the distribution range in the horizontal direction ( The decoupling is performed to approximate the volume solubility in a product form, which is more accurate than the traditional method.

[0110] (2) The first introduction of independent correction for grouting hole density: through This reflects the increased chances of slurry superposition and cross-contamination caused by different pore densities, filling the gap in the existing technology where the pore density effect has been systematically ignored.

[0111] (3) Grouting depth adaptable to various engineering types: Based on the different characteristics of natural foundations, pile foundations, and tunnels, the grouting section length is given. The determination method makes this method widely applicable.

[0112] (4) Strong dynamic applicability in stages: This method can flexibly adjust parameter values ​​and supplementary steps according to the data accuracy and decision-making needs of the feasibility study (preliminary design), construction drawing design, and construction stages, to achieve full life-cycle engineering quantity control from budget to settlement. In the feasibility study (preliminary design) stage, the borehole encounter rate is allowed. Approximate karst planar distribution coefficient This reduced the data requirements.

[0113] (5) Field test calibration and dynamic correction mechanism: Geological parameter deviations are eliminated through test calibration, and subsequent estimates are adjusted in real time through sliding average correction during construction, which significantly improves the estimation accuracy.

[0114] (6) The parameter system is clear and easy to operate: all parameters can be obtained through conventional surveys, geophysical exploration or field tests, the implementation cost is low, the formula is simple and easy for engineering technicians to master and apply.

[0115] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0116] Example 1 (Natural Foundation Engineering - Complete Estimation Process from Feasibility Study to Construction Drawing Design) 1. Project Overview: A multi-story building is planned to be constructed in a karst area, using a natural foundation (shallow foundation). The foundation depth is 2.0 m, the foundation bottom width is 20 m, and the length is 30 m. The treatment area is [area missing]. m 2 Preliminary geological surveys included 12 boreholes, 7 of which encountered karst caves. The survey report indicates that the caves are predominantly semi-filled, filled with soft plastic clay; the groundwater level is 3 m below the foundation bottom, with a slow flow velocity (still water conditions). The design proposes the spacing between grouting holes. m (plum blossom pattern), grouting pressure is 0.3~0.6 MPa.

[0117] 2. Phase One: Feasibility Study / Preliminary Design Estimation (1) Length of grouting section According to the borehole data, the shallowest cave ceiling is located 3.5 m below the ground surface, and the deepest cave floor is located 9.2 m below the ground surface. Following the principle of "2 m above the shallowest cave ceiling to 2 m below the deepest cave floor," the vertical distance is 9.7 m. m.

[0118] (2) Average linear yield of borehole The total length of the karst caves encountered in all boreholes is 3.8 m, and the total drilling depth through the soluble rock (limestone) is 32 m. .

[0119] (3) Karst planar distribution coefficient The feasibility study uses the borehole encounter rate as an approximation. (Cavity encounter rate) Based on the average size of the karst cave (horizontal projected area approximately 20–50 m²), 2 (Medium-sized), take the correction factor ,but .

[0120] (4) Other parameters: , (Median of semi-filled type) (Still water conditions, moderately developed fissures). (Hole spacing 2.0m).

[0121] Preliminary estimate: m 3 The initial estimated grouting volume is approximately 248 m³. 3 This data is used for investment estimation and scheme comparison. Due to limited survey data at this stage, the deviation between the estimated value and the final actual value is usually within ±50%.

[0122] 3. Phase Two: Construction Drawing Design (Precise Geophysical Measurement + On-site Grouting Test Calibration) As the detailed exploration progressed, high-density electrical resistivity tomography was used to determine the extent of the cave. The geophysical survey showed that the total horizontal projected area of ​​the cave was 372 m². 2 , After drilling with increased density, the linear flux ratio was recalculated. The length of the grouting section is slightly adjusted and rounded based on the depth of the deepest karst cave floor revealed by geophysical exploration. m, consistent with the previous stage.

[0123] Select a representative area (200 m²) on site. 2 Cross-hole seismic CT exploration and grouting tests were conducted. CT exploration obtained the actual karst development volume within the test area. m 3 After grouting according to the design parameters (grouting pressure 0.3~0.6MPa), record the actual grouting volume. m 3 Calculate the overall on-site coefficient: The test hole spacing is 2.0m ( Therefore, the calibrated comprehensive geological coefficient ,Right now Based on the borehole core analysis, the borehole was determined to be partially filled. Reverse calculation The increase from the initial estimate (0.20) indicates that the actual slurry loss was more severe than expected.

[0124] Using the calibrated comprehensive coefficient Re-estimate the total grouting volume for the entire site. m 3 According to statistics after the completion of construction, the final actual grouting volume was 340 m³. 3 The feasibility estimation deviation is then... (Within ±50%), the construction drawing estimation deviation is (Much better than ±30%). This demonstrates the technical effectiveness of the present invention's "staged estimation and gradual convergence".

[0125] 4. Note: The impact of different filling types If the same site is actually a cavity type ( If so, the estimated value of the calibrated construction drawings will become m 3 If it is a fully filled type ( ), then approximately m 3 The type of filling is a key controlling factor for the amount of grout injected, and it should be a key focus during the exploration phase.

[0126] Example 2 (Pile Foundation Engineering - Dynamic Correction and Boundary Locking during Construction) 1. Project Background: A pile foundation project, the design comprehensive coefficient marked during the construction drawing design stage. (Excluding hole density correction, hole spacing 2.0 m). Construction is carried out in sequence, with the goal of controlling the final grouting volume deviation through dynamic correction. The grouting pressure is 0.5–0.8 MPa. Site It is located in an area with strong karst development and requires boundary locking measures.

[0127] 2. Boundary locking measures First, implement edge locking measures around the perimeter of the site: install edge sealing holes at 1.5m intervals along the boundary; use cement-water glass double-liquid grout (volume ratio 1:0.6 to 1:1), with an initial setting time of 30 to 60 seconds; gradually increase the grouting pressure from 0.2 MPa to 0.8 MPa, and maintain the final pressure for 5 minutes; carry out continuous construction to ensure that adjacent edge sealing holes overlap to form a continuous grout-stopping curtain; construct the internal holes 72 hours after the edge locking is completed.

[0128] 3. First-order boreholes (6 m spacing): 25 boreholes were constructed, and the average grouting volume per unit was calculated. Due to the large hole spacing and weak grout superposition effect, the grouting volume is relatively low, and no adjustments will be made to the design.

[0129] 4. Secondary grouting units (spacing increased to 2.0 m): Divided into multiple grouting units, each unit containing 10 grouting holes. ① Unit 1: ,deviation No adjustment; ② Unit 2: ,deviation No adjustment; ③ Unit 3: Drilling encountered a group of beaded caves. ,deviation This triggers a sliding correction.

[0130] 5. Sliding Correction To construct the five data points required for the moving average, the statistical results (average value) of the first borehole construction stage were used. The result is broken down into two representative conversion values: the first conversion value is 1.10 (close to the statistical mean, rounded off), and the second conversion value is 1.15 (appropriately rounded up to reflect the transition trend from the first-order borehole to the second-order borehole). Combined with the actual values ​​of 1.58, 1.69, and 2.15 from the three completed second-order borehole units, five data points are formed: After moving average correction, Subsequent units adopt ,actual It remained stable between 1.49 and 1.55.

[0131] 6. Final statistics: Total actual grouting volume after all grouting is completed. m 3 The estimated value of 1043 m in the construction drawing design is consistent with the actual value. 3 The deviation was 5.5%. In addition, after the boundary was locked, the unit grouting volume of the internal holes decreased from the design estimate of 1.622 to the actual stable value of about 1.49 to 1.55, a reduction of about 5% to 8%, which prevented a large amount of grout from flowing out of the site.

[0132] 7. Note: Economic comparison of different hole spacings Based on the data from this project, if the hole spacing is 1.5 m ( The grouting volume increases by approximately 15.5%, but the drilling cost increases by approximately 78%; if the hole spacing is 2.5 m ( This reduces the grouting volume by approximately 10.6%, but there is a risk of incomplete treatment. A reference spacing of 2.0 m is recommended for grouting holes in general engineering projects.

[0133] Example 3 (Tunnel Engineering - Determination of Grouting Section Length) 1. Project Overview A tunnel in a karst area has a treatment section length of 120 m, a tunnel excavation width of 14 m, and a treatment area area of ​​[missing information]. m 2 Fifteen advanced geological boreholes revealed extremely uneven karst development depth beneath the tunnel floor: karst caves in the eastern section are distributed 3–10 m below the floor, while those in the western section are distributed 15–30 m below the floor. Assessment indicated that grouting treatment is required beneath the floor in all areas.

[0134] 2. If a uniform grouting section length is adopted. If a uniform depth of 30 m is taken for the bottom of the karst in the western section, the grouting section in the eastern section will be too deep, resulting in a large amount of waste; if a uniform depth of 10 m is taken for the bottom of the eastern section, the grouting in the western section will be severely insufficient and unable to cover the deep karst. Therefore, a zoning method is adopted.

[0135] 3. Partition Determination Based on the depth of the top and bottom slabs of the karst cave revealed by the boreholes, the tunnel treatment section was divided into two zones: ① Zone I (East Section): Length 60 m, Area m 2 The shallowest cave is 3m below the top and bottom slabs, and the deepest cave is 10m below the bottom slab. m (2 m below the bottom plate to 2 m below the deepest bottom plate).

[0136] ② Zone II (West Section): Length 60 m, Area m 2 The shallowest cave is 15m below the top and bottom slabs, and the deepest cave is 30m below the bottom slab. m (2m below the bottom plate to 2m below the deepest bottom plate).

[0137] Parameters for each partition: ① Zone I: , , ② Zone II: , , ③ Standardize parameters: , , 4. Partitioned Calculation: Zone I: m 3 Zone II: m 3 m 3 5. Effects Due to the significant difference in the depth of karst development beneath the tunnel floor in the eastern and western sections (eastern section) m, western section If a uniform grouting section length is adopted for the entire site (m), it will inevitably lead to excessive grouting in the eastern section or insufficient treatment in the western section. Therefore, a zoning method is used to determine the grouting section length separately. This effectively avoids estimation errors. In this embodiment, the total grouting volume using the zoning method is 3032 m³. 3 The results are largely consistent with the actual measured values.

[0138] Example 4 (Sensitivity Summary Analysis of Key Parameters) This embodiment summarizes and displays the quantitative impact of changes in each key parameter on the estimation results in tabular form (Table 1), illustrating the importance of taking reasonable values.

[0139] Preliminary estimate based on Example 1 m 3 (Baseline parameters:) , Using m (without boundary lock edge) as the comparison benchmark, we examine the change in grouting volume when a single parameter changes: Table 1 Comparison of Grouting Volume for Key Parameters in Different Scenarios Note: The edge-locking effect is calculated based on a reduction of approximately 15% in the unit grouting volume after edge-locking, which is derived from statistical experience of similar projects.

[0140] Sensitivity analysis conclusions: (1) The filling type is the most sensitive parameter: the grouting volume of the cavitary type and the fully filled type differs by about 3.7 times (413 vs 110). Therefore, it is crucial to accurately determine the filling type of the karst cave during the exploration stage. If necessary, borehole photography or in-hole radar detection should be used.

[0141] (2) The plane distribution coefficient has a significant impact. When the grouting volume increases from 0.40 to 0.80, the variation range is approximately -31.0% to +37.9%. When the feasibility study (preliminary design) stage uses the cavity encounter rate approximation, the correction factor... The appropriate value is crucial – it needs to be carefully judged based on the average size of the cave, and the median value should not be blindly chosen.

[0142] (3) The influence of the grout loss coefficient is moderately controllable. Within the range of 0.10 to 0.45, the grouting volume changes by approximately -8.9% to +25.0%. The actual value is affected by the degree of fracture development, groundwater conditions and grouting pressure. It can be calibrated through on-site grouting tests during the construction drawing design stage.

[0143] (4) The effect of hole density is relatively mild: when the hole spacing is reduced from 2.0 m to 1.5 m, the grouting volume increases by about 15%, but the number of holes increases by about 78%. The economic benefits need to be weighed comprehensively. The adjustment of hole spacing should be selected based on economic efficiency while ensuring the treatment effect.

[0144] (5) Significant boundary locking effect: Implementing boundary locking in areas with strong karst development can reduce the grouting loss of internal holes by about 15%, while reducing the environmental risk of grout flowing out of the site, thus having both technical and environmental benefits.

[0145] (6) Comprehensive effect: Under extreme combinations (cavitary type + high plane distribution + high pressure grouting + dense holes + no edge locking), the grouting volume can reach approximately the benchmark value. times, or approximately 820 m 3 Under a conservative combination (full filling + low planar distribution + low-pressure grouting + sparse porosity + edge locking), the efficiency can be as low as approximately the benchmark value. times, or approximately 53 m 3 The grouting volumes obtained from the two combinations differ significantly. Therefore, correctly selecting each parameter is crucial for the accurate application of this method, and in practical engineering, it should be determined comprehensively based on detailed surveys and field tests.

[0146] The above embodiments fully demonstrate the application of this invention in three engineering types: natural foundations, pile foundations, and tunnels, and in the three stages of feasibility study (preliminary design), construction drawing design, and construction. Sensitivity analyses are included regarding filling type, planar distribution coefficient, grout loss, pore density, and boundary locking. Those skilled in the art can directly implement the method of this invention based on these embodiments.

[0147] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for staged dynamic estimation of karst grouting volume, characterized in that, Includes the following steps: S1. Obtain the processing area area of ​​the site. The length of the grouting section was determined based on the karst exploration data after the site survey. L and average linear melting rate of borehole ; S2. Determine the following parameters: (a) Grouting range expansion coefficient , wherein The value range is 1.05 to 1.15; (b) Karst planar distribution coefficient , wherein Determined by the ratio of the total horizontal projected area of ​​the karst caves to the area of ​​the treatment area; (c) Karst volumetric grouting filling rate This is determined by the type of karst cave filling. The range of values ​​for , wherein when the karst cave is a cavity type, the The value range is 0.60 to 0.85; when the karst cave is semi-filled, the... The value range is 0.30 to 0.60; when the karst cave is fully filled, the value of... The value range is 0.10 to 0.30; (d) Slurry loss coefficient , wherein The value range is 0.05 to 0.45; (e) Grouting hole density correction factor , wherein Calculated using the following formula: in, Preset reference hole spacing, This refers to the actual spacing between grouting holes. It is an empirical index with a value range of 0.3 to 0.8; S3. Calculate the karst grouting volume : (i) When the karst development depth of the site is relatively uniform, a single zone is adopted, and the karst grouting volume is calculated according to the following formula. : in, To process the area, For the length of the grouting section, For the average linear yield of boreholes, For karst planar distribution coefficient, For karst volume grouting filling rate, For slurry loss coefficient, This is the correction factor for the density of the grouting holes; (ii) When the depth of karst development in the site varies greatly, the site shall be divided into several zones, the zones shall be numbered, and the length of the grouting section for each zone shall be determined. The karst grouting volume is calculated according to the following formula. : in, For partition numbering, For the first The processing area of ​​each partition. For the first The length of the grouting section in each zone, For the first Average linear melt rate of boreholes in each zone For the first Karst plane distribution coefficient of each zone, For the first The karst volumetric grouting filling rate of each zone For the first Slurry loss coefficient of each zone, For the first The grouting hole density correction factor for each zone.

2. The method as described in claim 1, characterized in that, The karst plane distribution coefficient It is obtained through the following steps: N1. The total horizontal projected area of ​​the karst cave is calculated by geophysical methods, wherein the geophysical methods are selected from the following group: high-density electrical resistivity tomography, cross-hole seismic CT, cross-hole radar, or a combination thereof; N2. Divide the sum of the horizontal projected areas of the karst caves obtained in step N1 by the total area of ​​the treated area. The karst planar distribution coefficient is obtained. ; In cases where karst exploration is in the feasibility study or preliminary design stage and geophysical data is lacking, the borehole encounter rate is calculated. And multiply by an empirical correction factor After adjustment, it replaces the above. The borehole encounter rate The result is obtained by the following formula: in, To determine the number of boreholes in the cave, The total number of boreholes; the empirical correction factor. The range of values ​​is determined by the size and distribution characteristics of the karst caves. Specifically, when the karst caves are large and their distribution is continuous... The value range is 1.0~1.2; when the cave is of medium size and the caves are relatively evenly distributed, The value range is 1.2 to 1.3; when the caves are small in scale, isolated in distribution, and appear as points, The value range is 1.3 to 1.

5.

3. The method as described in claim 1, characterized in that, The length of the grouting section Determined in the following ways: When the site is a natural foundation, the length of the grouting section is... The grouting section extends from the base surface to the designed treatment depth, where the designed treatment depth is 5–10 m below the base or to intact bedrock, or the length of the grouting section depends on the depth of the karst cave distribution. It extends from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than the depth of the foundation compression layer. When the site is a pile foundation project, the length of the grouting section is... The depth ranges from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than 3 to 5 m below the pile tip. When the site is a tunnel project, the length of the grouting section is... The thickness of the radial reinforcement ring outside the tunnel excavation outline, or the length of the grouting section. The distribution range of karst caves was determined based on advanced geological forecasts.

4. The method as described in claim 1, characterized in that, The method further includes an on-site grouting test calibration step, which includes the following steps: Y1. Select a test block within the treatment area, wherein the area of ​​the test block is not less than 200 m². 2 ; Y2. Obtain the true karst development volume through geophysical methods. Grouting was then carried out and the actual grouting volume was recorded. Calculate the overall coefficient on site The geophysical methods described herein are selected from the group consisting of: high-density electrical resistivity tomography, trans-pore seismic CT, trans-pore radar, or combinations thereof; The result is obtained by the following formula: Y3, will and A comparison is made, and when the deviation between the two exceeds 30%, then... or Adjustments will be made.

5. The method as described in claim 1, characterized in that, The method further includes a dynamic correction step, which includes the following steps: Z1. Divide the holes for grouting construction into first-order holes, second-order holes and third-order holes, and divide the hole sequence into multiple grouting units; Z2. After each grouting unit is completed, calculate the actual grouting volume per unit volume. , wherein The following formula is used to calculate: ； Simultaneously, the design comprehensive coefficient is calculated. , wherein It is obtained by calculation using the following formula; and Design integration coefficient Compare; when and When the relative deviation exceeds 20%, the design comprehensive coefficient of the subsequent grouting unit shall be corrected by moving average according to the following formula: Among them, when the project site is of medium to large size and the total number of grouting units is not less than 20, The value is 5 to 10; when the site is small and the total number of grouting units is less than 10, This represents the total number of all constructed units.

6. The method as described in claim 1, characterized in that, In calculating the grouting hole density correction factor At that time, the preset reference hole spacing The value range is 1.0 to 3.0 m. The experience index The range of values ​​is determined based on the degree of karst development, among which, When the karst site is an isolated cave site, the empirical index The value range is 0.3 to 0.4; When the karst site is a typical karst site, the empirical index The value range is 0.4 to 0.6; When the karst site is a highly developed and interconnected site, the empirical index... The value range is 0.6 to 0.

8.

7. The method as described in claim 1, characterized in that, The slurry loss coefficient The value range is determined by the degree of fracture development, groundwater flow conditions, and grouting pressure. When the fissures are not well-developed, the groundwater flow conditions are static, and / or the grouting pressure is low, the The value range is 0.05 to 0.15; When the fissure is moderately developed, the The value range is 0.15 to 0.25; When the fissures are dense, the groundwater flow conditions are dynamic, and / or the grouting pressure is high, the following The value range is 0.25 to 0.

45.

8. The method as described in claim 1, characterized in that, The length of the grouting section Determine using the following steps: X1. Based on the depth of the top and bottom plates of the karst caves revealed by the boreholes, draw karst development contour maps and divide the site into several karst development zones. X2. When the site is a natural foundation, the length of the grouting section. For the first Within each zone, the grouting section extends from the foundation bottom surface to the designed treatment depth, where the designed treatment depth is 5–10 m below the foundation or to intact bedrock, or, depending on the depth of the karst cave distribution, the length of the grouting section. It extends from 2 m above the top of the shallowest cave to 2 m below the bottom of the deepest cave, and is not less than the depth of the foundation compression layer. When the site is a pile foundation project, the length of the grouting section is... For the first Within each zone, the shallowest cave's top slab extends from 2 m above the top slab to 2 m below the bottom slab of the deepest cave, and is not less than 3 to 5 m below the pile tip; When the site is a tunnel project, the length of the grouting section is... For the first The thickness of the radial reinforcement ring outside the tunnel excavation outline within each zone, or the thickness of the karst cave distribution range determined by advanced geological forecasting.

9. The method as described in claim 1, characterized in that, The karst volume grouting filling rate The range of values ​​is determined based on the type of karst cave filling and existing engineering experience. When the type of karst cave filling is a hollow karst cave, the The value range is 0.60 to 0.85; When the cave filling type is a semi-filled cave, the The value range is 0.30 to 0.60; When the cave filling type is a fully filled cave, the The value range is 0.10 to 0.

30.

10. The method as described in claim 1, characterized in that, The method also includes a boundary locking step: M1, for karst planar distribution coefficient In the treated area, first construct sealing holes along the boundary of the treated area to form a grouting curtain, and then construct the internal holes.

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