Method for determining effective diffusion distance formula of grouting in water-rich sand layer

Abstract

The present invention relates to the field of diffusion testing technology, and specifically to a method for determining a formula for effective diffusion distance of penetration grouting in water-rich sand layers. A water-rich sand layer grouting model test platform is built, an orthogonal model test is carried out on the test platform and test data is obtained. According to dimensional analysis theory and in combination with the test data of the orthogonal model test, a calculation formula for the diffusion distance of penetration grouting in water-rich sand layers is derived. Stone body cores are drilled at different diffusion distances of a stone body formed in the grouting test platform. A relationship between a slurry filling rate and a corresponding actual diffusion distance of the slurry is constructed according to the slurry filling rate in the drill core at different positions. The corresponding diffusion distance is obtained through the relationship between the slurry filling rate and the corresponding diffusion distance. The corresponding diffusion distance is compared with the actual diffusion distance of the slurry to obtain a reduction coefficient. The reduction coefficient is substituted into the calculation formula for the diffusion distance of penetration grouting in water-rich sand layers to obtain a calculation formula for the effective diffusion distance of penetration grouting in water-rich sand layers.

Description

Technical Field

[0001] The invention relates to the technical field of diffusion testing, and in particular to a method for determining a formula for effective diffusion distance of penetration grouting in a water-rich sand layer. Background Art

[0002] Water-rich sand layers pose a significant safety risk in underground engineering construction. Grouting technology has become one of the key construction measures for sealing groundwater and reinforcing weak strata in underground engineering. Engineering practice has shown that when grouting sandy strata with good injectability, the slurry primarily diffuses through penetration. Under pressure, the slurry fills and penetrates into the pores of the sand layer, cementing the loose particles into a whole, thereby improving the strength and anti-seepage properties of the stratum. Currently, the determination of the diffusion distance of penetrating grouting in water-rich sand layers is mostly based on a comprehensive consideration of the rheological equation and equilibrium equation of the fluid to establish a theoretical model for penetrating grouting diffusion in water-rich sand layers. Based on this theoretical model, an expression for the penetrating grouting diffusion distance is derived. However, the effectiveness of grouting reinforcement and plugging depends on the strength and anti-seepage properties of the grouting stone body. Compared with the penetrating grouting diffusion distance, the effective reinforcement and plugging distance of penetrating grouting diffusion has more practical engineering application value. However, simple theoretical analysis also has certain limitations. Theoretical derivation is often based on multiple basic assumptions, and the calculated results often have large errors compared to the actual values.

[0003] Therefore, a scientific and reasonable method for determining the effective diffusion distance of grouting in water-rich sand layers is proposed, which has important reference value for guiding the design of actual engineering grouting schemes, optimizing grouting parameters, and improving the grouting reinforcement and plugging effect. To this end, a method for determining the effective diffusion distance of grouting in water-rich sand layers is proposed. Summary of the Invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention provides a method for determining a formula for the effective diffusion distance of grouting in water-rich sand layers.

[0005] To solve the above technical problems, the present invention provides the following technical solution: a method for determining a formula for effective diffusion distance of grouting in water-rich sand layers, comprising the following steps:

[0006] Step S1: build a water-rich sand layer grouting model test platform, and carry out factor Conduct horizontal orthogonal model tests and obtain test data;

[0007] Step S2, analyzing the test data of the orthogonal model test using dimensional analysis theory to derive a mathematical relationship for the actual diffusion distance of the slurry;

[0008] Step S3: taking out the stone body formed in the grouting test platform, drilling holes at different distances from the stone body to obtain stone body cores, measuring and quantifying the slurry filling rate in the stone body cores, and constructing a relationship between the slurry filling rate and the corresponding diffusion distance based on the slurry filling rate in the stone body cores at different diffusion distances;

[0009] Step S4, conduct penetration and uniaxial compression tests on the stone core at different diffusion distances to obtain test results, draw a three-dimensional graph by fitting the test results, find the mutation point from the three-dimensional graph, clarify the slurry filling rate corresponding to the mutation point, obtain the corresponding diffusion distance through the relationship between the slurry filling rate and the corresponding diffusion distance, compare the corresponding diffusion distance with the actual diffusion distance of the slurry to obtain the reduction coefficient, substitute the reduction coefficient into the calculation formula of the diffusion distance of the water-rich sand layer penetration grouting to obtain the calculation formula of the effective diffusion distance of the water-rich sand layer penetration grouting.

[0010] Preferably, the step S1 includes:

[0011] Step S11, building a water-rich sand layer grouting model test platform;

[0012] Step S12, design factor Horizontal orthogonal model test, through the water-rich sand layer grouting model test platform, the grouting test is carried out in sequence according to the designed orthogonal model test, and the actual diffusion distance of the slurry in the test is recorded after each group of tests .

[0013] Preferably, in step S11, the water-rich sand layer grouting model test platform includes a grouting test device, a grouting system, a pseudo-groundwater pressurization system and a data acquisition system;

[0014] The grouting test device is used to simulate a water-rich sand layer. The grouting system is connected to one end of the grouting test device. The grouting system is used to inject grouting liquid into the simulated water-rich sand layer.

[0015] The pseudo-groundwater pressurization system is connected to both ends of the grouting test device, and is used to maintain the dynamic transfer of water in the simulated water-rich sand layer during the grouting process;

[0016] The data acquisition system's acquisition end is arranged inside the grouting test device, and the grouting test device is used to acquire data during the grouting test process.

[0017] Preferably, in step S12, Factor is grouting pressure , grouting volume and permeability , Choose from 4 levels.

[0018] Preferably, the step S2 includes:

[0019] Step S21: derive the actual diffusion distance of the slurry based on dimensional analysis theory The mathematical relationship is:

[0020] ;

[0021] In the formula is the actual diffusion distance of the slurry, is the grouting pressure, is the grouting volume, is the permeability, 、 、 and is the constant to be determined;

[0022] Step S22: based on the actual diffusion distance of the slurry in each group of experiments The data was fitted and solved by data processing software. 、 、 and , the obtained 、 、 and Substitute and improve the actual diffusion distance of the slurry The mathematical relationship of .

[0023] Preferably, step S3 includes:

[0024] Step S31: After the grouting test is completed, the stone body formed in the grouting test platform is subjected to room temperature curing for 7 days. After the curing is completed, the stone body is divided into sections along the central axis, with equal spacing between each section. Nine sampling positions are planned in each section. Coring operations are carried out in sequence according to the divided sampling positions to obtain stone body cores. Each stone body core is polished into a cylinder of uniform specifications. The polished stone body cores are arranged according to the sampling position. All stone body cores in the same row are considered as an inspection group.

[0025] Step S32: Select the test group located on the central axis of the stone body, and use the scanning electron microscope and low-field nuclear magnetic resonance micro-observation equipment to test and quantify the slurry filling rate in the gap of each stone body core section in the test group. , the slurry filling rate of the stone core The sampling position of the core of the stone body is used as a coordinate point, and the slurry filling rate is established based on all the coordinate points in a test group. and the corresponding diffusion distance of the slurry The relationship:

[0026] .

[0027] Preferably, in step S4, the reduction coefficient includes the reduction coefficient of the effective reinforcement distance and the reduction factor of the effective plugging distance The calculation formula of the effective diffusion distance of water-rich sand layer penetration grouting includes the effective reinforcement distance of water-rich sand layer penetration grouting diffusion Effective plugging distance of penetration grouting and diffusion in water-rich sand layer .

[0028] Preferably, the step S4 includes:

[0029] Step S41, selecting a test group located on the adjacent side of the central axis of the stone body, sequentially performing uniaxial compression tests on the stone body cores in the test group and obtaining compressive strength data of each stone body core in the test group, and performing fitting analysis on all the obtained compressive strength data;

[0030] Step S42: Draw a three-dimensional graph of compressive strength, filling rate and diffusion distance based on the fitting analysis results, find the compressive strength mutation point from the three-dimensional graph, and determine the slurry filling rate corresponding to the compressive strength mutation point. ;

[0031] Step S43, the slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry In the relationship between The corresponding diffusion distance The diffusion effective reinforcement distance , effectively strengthening the diffusion distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective reinforcement distance. ;

[0032] Step S44, actual diffusion distance to the slurry The reduction factor of effective reinforcement distance is introduced into the calculation formula , obtain the effective reinforcement distance of diffusion of water-rich sand layer infiltration grouting The calculation formula is:

[0033] ;

[0034] Step S45, selecting another test group located on an adjacent side of the central axis of the stone body, sequentially performing a permeability water flooding test on the stone body cores in the test group to obtain permeability data for each stone body core in the test group, and performing fitting analysis on the permeability data of samples of different cross sections obtained from the permeability water flooding test;

[0035] Step S46: Draw a three-dimensional graph of permeability, filling rate and diffusion distance based on the fitting analysis results, find the permeability mutation point from the three-dimensional graph, and determine the slurry filling rate corresponding to the permeability mutation point. ;

[0036] Step S47, the slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry In the relationship between The corresponding diffusion distance That is the effective plugging distance of diffusion , will spread the effective plugging distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective plugging distance. :

[0037] Step S48, actual diffusion distance to the slurry The reduction coefficient of effective plugging distance is introduced into the calculation formula , obtain the effective plugging distance of diffusion of water-rich sand layer penetration grouting The calculation formula is:

[0038] .

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] 1. The present invention sets up a water-rich sand layer grouting model test platform, and conducts orthogonal experimental research on multiple factors such as grouting pressure, grouting volume, and permeability. According to dimensional analysis theory and combined with model test results, a calculation formula for the diffusion distance of grouting in water-rich sand layers is derived. Based on core sampling tests at different diffusion distances in the model test, a corresponding relationship between slurry filling rate and diffusion distance is constructed. The calculation formula for effective reinforcement and plugging distance is derived from performance improvement and filling efficiency. The calculation formula for effective reinforcement and plugging distance can guide the design of actual engineering grouting schemes, optimize grouting parameters, and achieve the purpose of improving the grouting reinforcement and plugging effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 1 is a flow chart of a method for determining a formula for effective diffusion distance of grouting in water-rich sand layers according to an embodiment of the present invention;

[0042] Figure 2 Schematic diagram of a water-rich sand layer grouting model test platform according to an embodiment of the present invention;

[0043] Figure 3 The grouting rate and diffusion distance of the water-rich sand layer grouting model test in the embodiment of the present invention are 、 and Schematic diagram of the relationship;

[0044] Figure 4 Schematic diagram of the coring position of the stone body in the grouting model test of the water-rich sand layer according to the embodiment of the present invention;

[0045] Figure 5 is a schematic diagram of the relationship between compressive strength, filling rate and diffusion distance in an embodiment of the present invention;

[0046] Figure 6 Schematic diagram of the relationship among permeability, filling rate and diffusion distance in an embodiment of the present invention.

[0047] The numbers in the figure represent:

[0048] 1. Grouting test device; 11. Reaction frame; 12. Grouting test chamber; 13. Permeable stone; 14. Water-rich sand layer; 15. Slurry control valve; 16. Loading plate; 17. Loading cylinder; 18. Hydraulic servo controller; 2. Grouting system; 21. Grouting pump; 22. Liquid A storage tank; 23. Liquid B storage tank; 24. Slurry pipeline; 3. Pseudo-groundwater pressurization system; 31. Air compressor; 32. First water pipe; 33. Second water pipe; 34. Water tank; 4. Data acquisition system; 41. Data acquisition instrument; 42. Osmotic pressure sensor; 43. Resistivity sensor; 44. Flat membrane pressure transmitter; 45. Grouting pressure sensor; 46. PC. DETAILED DESCRIPTION

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein the above and other technical features and advantages of the present invention are described below. However, the following embodiments are merely embodiments of the present invention and are not exhaustive.

[0050] Example:

[0051] like Figures 1-6 As shown, the present invention provides a method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting, including:

[0052] Build a water-rich sand layer grouting model test platform, which includes a grouting test device 1, a grouting system 2, a pseudo-groundwater pressurization system 3 and a data acquisition system 4;

[0053] The grouting test device 1 is used to simulate a water-rich sand layer. The grouting test device 1 includes a reaction frame 11, a grouting test chamber 12, a permeable stone 13, a water-rich sand layer 14, a slurry control valve 15, a loading plate 16, a loading cylinder 17, and a hydraulic servo controller 18.

[0054] The reaction frame 11 is placed flat on the horizontal ground, the grouting test chamber 12 is set on one side of the reaction frame 11, one end of the grouting test chamber 12 is in conflict with one side of the inner wall of the reaction frame 11, two groups of permeable stones 13 are respectively filled at both ends of the interior of the grouting test chamber 12, and the water-rich sand layer 14 is filled in the middle position of the grouting test chamber 12. The slurry control valve 15 passes through the reaction frame 11 and the permeable stone 13 and is inserted into the grouting test chamber 12. The loading plate 16 is set on the other end of the grouting test chamber 12, and the loading cylinder 17 is set at the reaction frame 11. On the other side of the frame 11, the base of the loading cylinder 17 contacts the inner wall of the reaction frame 11, and the movable end of the loading cylinder 17 contacts the loading plate 16. The hydraulic servo controller 18 is connected to the loading cylinder 17 through a hydraulic pipeline. During the test process, the hydraulic servo controller 18 supplies hydraulic pressure to the loading cylinder 17 through the hydraulic pipeline. The loading cylinder 17 works to push the loading plate 16 to move horizontally along the grouting test chamber 12. During the horizontal movement process, the grouting test chamber 12 squeezes the permeable stone 13 and the water-rich sand layer 14 to simulate the pressure environment;

[0055] The grouting system 2 is connected to one end of the grouting test device 1. The grouting system 2 is used to inject grouting liquid into the simulated water-rich sand layer. The grouting system 2 includes a grouting pump 21, a liquid A storage tank 22, a liquid B storage tank 23 and a slurry delivery pipeline 24. The grouting pump 21 is arranged outside the reaction frame 11. The liquid A storage tank 22 and the liquid B storage tank 23 are connected to the input end of the grouting pump 21 through a feed pipeline. The two ends of the slurry delivery pipeline 24 are respectively connected to the output end of the grouting pump 21 and the input end of the slurry control valve 15;

[0056] During grouting, the grouting pump 21 extracts and mixes the slurry from the A liquid storage tank 22 and the B liquid storage tank 23, and then injects the slurry into the water-rich sand layer 14 through the slurry pipeline 24 and the slurry control valve 15;

[0057] The pseudo-groundwater pressurization system 3 is respectively connected to both ends of the grouting test device 1. The pseudo-groundwater pressurization system 3 is used to maintain the dynamic transfer of water in the simulated water-rich sand layer during the grouting process. The pseudo-groundwater pressurization system 3 includes an air compressor 31, a first water pipe 32, a second water pipe 33 and a water tank 34. The air compressor 31 is provided in two groups of permeable stones 13. The input ends of the two groups of air compressors 31 are connected to the first water pipe 32. The ends of the two groups of first water pipes 32 are respectively connected to the two groups. The output ends of the two groups of air compressors 31 are connected to the second water pipe 33. The water inlet of the water tank 34 is connected to the two groups of second water pipes 33 at the same time.

[0058] Under the pressure of the air compressor 31, the water in the water tank 34 flows dynamically into the permeable stone 13 through the second water pipe 33 and the first water pipe 32;

[0059] The collection end of the data acquisition system 4 is arranged inside the grouting test device 1. The data acquisition system 4 is used to collect data during the grouting test. The data acquisition system 4 includes a data acquisition instrument 41, a permeability pressure sensor 42, a resistivity sensor 43, a flat membrane pressure transmitter 44, a grouting pressure sensor 45 and a PC 46. The data acquisition instrument 41 is placed outside the grouting test device 1. The permeability pressure sensor 42, the resistivity sensor 43, the flat membrane pressure transmitter 44 and the grouting pressure sensor 45 are all electrically connected to the data acquisition instrument 41. The end of the permeability pressure sensor 42 is buried at the center of the water-rich sand layer 14, and the end of the resistivity sensor 43 is buried at the edge of the water-rich sand layer 14. The grouting pressure sensor 45 is connected to the slurry control valve 15. The PC 46 is electrically connected to the data acquisition instrument 41. The data collected by the permeability pressure sensor 42, the resistivity sensor 43, the flat membrane pressure transmitter 44 and the grouting pressure sensor 45 are finally sent to the PC 46 via the data acquisition instrument 41.

[0060] During the test, the osmotic pressure sensor 42 collects osmotic pressure data, and the resistivity sensor 43 collects resistivity change data. The resistivity change can reflect the diffusion distance of the slurry, thereby obtaining the actual diffusion distance. ;

[0061] The flat membrane pressure transmitter 44 collects the flat membrane pressure data changes, and the grouting pressure sensor 45 monitors the grouting pressure data. The collected data are summarized at the data acquisition instrument 41 and transmitted to the PC 46 by the data acquisition instrument 41.

[0062] Relying on the water-rich sand layer grouting model test platform, a three-factor four-level orthogonal model test was carried out. The three factors are grouting pressure P, grouting volume Q and permeability K.

[0063] Grouting pressure P is 2 , 3 , 4 and 5 Four levels;

[0064] The grouting volume Q is 0.005 , 0.006 , 0.007 and 0.008 Four levels;

[0065] Permeability K is 0.01 , 0.05 , 0.1 and 0.15 Four levels;

[0066] The orthogonal model experimental design table shown in Table 1 is formed.

[0067] Table 1. Orthogonal model test design table

[0068] serial number #timg# / MPa #timg# / #timg# #timg# / #timg# serial number #timg# / MPa #timg# / #timg# #timg# / #timg# P1 2 0.005 0.01 P9 4 0.005 0.10 P2 2 0.006 0.05 P10 4 0.006 0.15 P3 2 0.007 0.10 P11 4 0.007 0.01 P4 2 0.008 0.15 P12 4 0.008 0.05 P5 3 0.005 0.05 P13 5 0.005 0.15 P6 3 0.006 0.01 P14 5 0.006 0.10 P7 3 0.007 0.15 P15 5 0.007 0.05 P8 3 0.008 0.10 P16 5 0.008 0.01

[0069] The grouting test was carried out in sequence according to the data in Table 1 through the water-rich sand layer grouting model test platform. The actual diffusion distance of the slurry in the test was recorded after each test. ;

[0070] The results are summarized and recorded to form the actual diffusion distance of the slurry shown in Table 2 Statistical table.

[0071] Table 2. Actual diffusion distance of slurry Statistics

[0072] serial number #timg# / m serial number #timg# / m P1 0.93 P9 1.67 P2 1.09 P10 1.61 P3 1.08 P11 1.55 P4 1.08 P12 1.55 P5 1.48 P13 1.84 P6 1.40 P14 1.82 P7 1.40 P15 1.80 P8 1.38 P16 1.67

[0073] Using dimensional analysis theory to analyze the data in Table 1 and Table 2, the actual diffusion distance of the slurry is deduced. The mathematical relationship is:

[0074] ;

[0075] In the formula is the actual diffusion distance of the slurry, is the grouting pressure, is the grouting volume, is the permeability, 、 、 and is the constant to be determined;

[0076] According to the actual diffusion distance of the slurry in Table 2 The statistical data were used to fit the constants using the data processing software Origin. 、 、 and , the solution is 、 、 and Substitute and obtain the actual diffusion distance of the perfect slurry The mathematical relationship is:

[0077] ;

[0078] After the grouting test, the stone body formed in the grouting test platform is maintained at room temperature for 7 days. Figure 4As shown in the figure, after the curing is completed, the stone body is divided into sections along the central axis, with equal spacing between each section. Nine sampling positions are planned in each section, and coring operations are carried out in sequence according to the divided sampling positions to obtain stone body cores. Each stone body core is polished into a cylinder with uniform specifications. The polished stone body cores are arranged according to the sampling positions, and all stone body cores in the same row are considered as one inspection group.

[0079] The test group located on the central axis of the stone body was selected, and the slurry filling rate in the cross-section of each stone core in the test group was tested and quantified using scanning electron microscopy and low-field nuclear magnetic resonance micro-observation equipment. , the slurry filling rate of the stone core The sampling position of the core of the stone body is used as a coordinate point, and the slurry filling rate is established based on all the coordinate points in a test group. and the corresponding diffusion distance of the slurry The relationship:

[0080]

[0081] Conduct permeability and uniaxial compression tests on the core of the stone body at different diffusion distances to obtain test results. Fit the test results to draw a three-dimensional graph. Find the mutation point from the three-dimensional graph and determine the slurry filling rate corresponding to the mutation point. Obtain the corresponding diffusion distance through the relationship between the slurry filling rate and the corresponding diffusion distance. Compare the corresponding diffusion distance with the actual diffusion distance of the slurry to obtain the reduction coefficient, which includes the reduction coefficient of the effective reinforcement distance. and the reduction factor of the effective plugging distance ;

[0082] Substituting the reduction coefficient into the calculation formula of the diffusion distance of the water-rich sand layer penetration grouting, the calculation formula of the effective diffusion distance of the water-rich sand layer penetration grouting is obtained. The calculation formula of the effective diffusion distance of the water-rich sand layer penetration grouting includes the effective reinforcement distance of the water-rich sand layer penetration grouting diffusion. Effective plugging distance of penetration grouting and diffusion in water-rich sand layer ;

[0083] A test group located on the adjacent side of the central axis of the stone body was selected, and a uniaxial compression test was performed on each stone body core in each test group in turn to obtain the compressive strength data of the stone body core, and the obtained compressive strength data were fitted and analyzed;

[0084] like Figure 5 As shown in the figure, a three-dimensional graph of compressive strength, filling rate and diffusion distance is drawn according to the fitting analysis results. The compressive strength mutation point is found from the three-dimensional graph. A compressive strength mutation point is randomly selected and the slurry filling rate corresponding to the selected compressive strength mutation point is determined. ;

[0085] Slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry In the relationship between The corresponding diffusion distance The diffusion effective reinforcement distance , effectively strengthening the diffusion distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective reinforcement distance. ;

[0086] Actual diffusion distance to the slurry The reduction factor of effective reinforcement distance is introduced into the calculation formula , obtain the effective reinforcement distance of diffusion of water-rich sand layer infiltration grouting The calculation formula is:

[0087] ;

[0088] Select another test group located on the adjacent side of the stone body's central axis, conduct water-flooding tests on the stone body cores in the test group in turn, and obtain the permeability data of each stone body core in the test group. Perform fitting analysis on the permeability data of samples of different cross-sections obtained from the water-flooding tests.

[0089] like Figure 6 As shown in the figure, a three-dimensional graph of permeability, filling rate and diffusion distance is drawn according to the fitting analysis results. The permeability mutation point is found from the three-dimensional graph. A permeability mutation point is randomly selected to determine the slurry filling rate corresponding to the selected permeability mutation point. ;

[0090] Slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry The relationship between the slurry filling rate and the The corresponding diffusion distance That is the effective plugging distance of diffusion , will spread the effective plugging distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective plugging distance. ;

[0091] Actual diffusion distance to the slurry The reduction coefficient of effective plugging distance is introduced into the calculation formula , obtain the effective plugging distance of diffusion of water-rich sand layer penetration grouting The calculation formula is:

[0092] .

[0093] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative rather than restrictive of the present invention. Those skilled in the art will appreciate that many changes, modifications, and even equivalents may be made to the present invention within the spirit and scope of the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A method for determining the effective diffusion distance of grouting in water-rich sand layers, characterized by: The following steps are involved: Step S1: build a water-rich sand layer grouting model test platform, and carry out factor Conduct horizontal orthogonal model tests and obtain test data; Step S2, analyzing the test data of the orthogonal model test using dimensional analysis theory to derive a mathematical relationship for the actual diffusion distance of the slurry; Step S3: taking out the stone body formed in the grouting test platform, drilling holes at different distances from the stone body to obtain stone body cores, measuring and quantifying the slurry filling rate in the stone body cores, and constructing a relationship between the slurry filling rate and the corresponding diffusion distance based on the slurry filling rate in the stone body cores at different diffusion distances; Step S4, conduct penetration and uniaxial compression tests on the stone core at different diffusion distances to obtain test results, draw a three-dimensional graph by fitting the test results, find the mutation point from the three-dimensional graph, clarify the slurry filling rate corresponding to the mutation point, obtain the corresponding diffusion distance through the relationship between the slurry filling rate and the corresponding diffusion distance, compare the corresponding diffusion distance with the actual diffusion distance of the slurry to obtain the reduction coefficient, substitute the reduction coefficient into the calculation formula of the diffusion distance of the water-rich sand layer penetration grouting to obtain the calculation formula of the effective diffusion distance of the water-rich sand layer penetration grouting.

2. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 1 is characterized in that: The step S1 comprises: Step S11, building a water-rich sand layer grouting model test platform; Step S12, design factor Horizontal orthogonal model test, through the water-rich sand layer grouting model test platform, the grouting test is carried out in sequence according to the designed orthogonal model test, and the actual diffusion distance of the slurry in the test is recorded after each group of tests .

3. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 2 is characterized in that: In step S11, the water-rich sand layer grouting model test platform includes a grouting test device, a grouting system, a pseudo groundwater pressurization system and a data acquisition system; The grouting test device is used to simulate a water-rich sand layer. The grouting system is connected to one end of the grouting test device. The grouting system is used to inject grouting liquid into the simulated water-rich sand layer. The pseudo-groundwater pressurization system is connected to both ends of the grouting test device, and is used to maintain the dynamic transfer of water in the simulated water-rich sand layer during the grouting process; The data acquisition system's acquisition end is arranged inside the grouting test device, and the grouting test device is used to acquire data during the grouting test process.

4. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 2, characterized in that: In the step S12, Factor is grouting pressure , grouting volume and penetration , Choose from 4 levels.

5. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 1, characterized in that: The step S2 comprises: Step S21: derive the actual diffusion distance of the slurry based on dimensional analysis theory The mathematical relationship is: ； In the formula is the actual diffusion distance of the slurry, is the grouting pressure, is the grouting volume, is the permeability, 、 、 and is the constant to be determined; Step S22: based on the actual diffusion distance of the slurry in each group of experiments The data was fitted and solved by data processing software. 、 、 and , the obtained 、 、 and Substitute and improve the actual diffusion distance of the slurry The mathematical relationship of .

6. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 1, characterized in that: The step S3 comprises: Step S31: After the grouting test is completed, the stone body formed in the grouting test platform is subjected to room temperature curing for 7 days. After the curing is completed, the stone body is divided into sections along the central axis, with equal spacing between each section. Nine sampling positions are planned in each section. Coring operations are carried out in sequence according to the divided sampling positions to obtain stone body cores. Each stone body core is polished into a cylinder of uniform specifications. The polished stone body cores are arranged according to the sampling position. All stone body cores in the same row are considered as an inspection group. Step S32: Select the test group located on the central axis of the stone body, and use the scanning electron microscope and low-field nuclear magnetic resonance micro-observation equipment to test and quantify the slurry filling rate in the gap of each stone body core section in the test group. , the slurry filling rate of the stone core The sampling position of the core of the stone body is used as a coordinate point, and the slurry filling rate is established based on all the coordinate points in a test group. and the corresponding diffusion distance of the slurry The relationship: 。 7. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 1, characterized in that: In step S4, the reduction coefficient includes the reduction coefficient of the effective reinforcement distance and the reduction factor of the effective plugging distance The calculation formula of the effective diffusion distance of water-rich sand layer penetration grouting includes the effective reinforcement distance of water-rich sand layer penetration grouting diffusion Effective plugging distance of penetration grouting and diffusion in water-rich sand layer .

8. The method for determining the effective diffusion distance formula of water-rich sand layer penetration grouting according to claim 7, characterized in that: The step S4 comprises: Step S41, selecting a test group located on the adjacent side of the central axis of the stone body, sequentially performing uniaxial compression tests on the stone body cores in the test group and obtaining compressive strength data of each stone body core in the test group, and performing fitting analysis on all the obtained compressive strength data; Step S42: Draw a three-dimensional graph of compressive strength, filling rate and diffusion distance based on the fitting analysis results, find the compressive strength mutation point from the three-dimensional graph, and determine the slurry filling rate corresponding to the compressive strength mutation point. ; Step S43, the slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry In the relationship between The corresponding diffusion distance The effective reinforcement distance of diffusion , effectively strengthening the diffusion distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective reinforcement distance. ; Step S44, actual diffusion distance to the slurry The reduction factor of effective reinforcement distance is introduced into the calculation formula , obtain the effective reinforcement distance of diffusion of water-rich sand layer infiltration grouting The calculation formula is: ； Step S45, selecting another test group located on an adjacent side of the central axis of the stone body, sequentially performing a permeability water flooding test on the stone body cores in the test group to obtain permeability data for each stone body core in the test group, and performing fitting analysis on the permeability data of samples of different cross sections obtained from the permeability water flooding test; Step S46: Draw a three-dimensional graph of permeability, filling rate and diffusion distance based on the fitting analysis results, find the permeability mutation point from the three-dimensional graph, and determine the slurry filling rate corresponding to the permeability mutation point. ; Step S47, the slurry filling rate Brought into the slurry filling rate and the corresponding diffusion distance of the slurry In the relationship between The corresponding diffusion distance That is the effective plugging distance of diffusion , will spread the effective plugging distance Actual diffusion distance from the slurry The ratio is the reduction coefficient of the effective plugging distance. : Step S48, actual diffusion distance to the slurry The reduction coefficient of effective plugging distance is introduced into the calculation formula , obtain the effective plugging distance of diffusion of water-rich sand layer penetration grouting The calculation formula is: 。

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