Water-rich sand layer permeation grouting diffusion effective distance formula determination method

Abstract

The invention relates to the technical field of diffusion testing, in particular to a water-rich sand layer permeation grouting diffusion effective distance formula determination method, which comprises the following steps: building a water-rich sand layer grouting model test platform, carrying out an orthogonal model test by virtue of the test platform, obtaining test data, and determining the effective distance of permeation grouting diffusion of a water-rich sand layer according to a dimensional analysis theory in combination with the test data of the orthogonal model test. Deriving a calculation formula of the permeation grouting diffusion distance of the water-rich sand layer, drilling holes at different diffusion distances of a stone body formed in the grouting test platform to obtain a stone body rock core, and constructing a relational expression between the slurry filling rate and the actual diffusion distance of the corresponding slurry according to the slurry filling rate in the drilled core at different positions; and the corresponding diffusion distance is obtained through the relational expression of the grout filling rate and the corresponding diffusion distance, the corresponding diffusion distance is compared with the actual diffusion distance of the grout to obtain a reduction coefficient, and the reduction coefficient is substituted into the calculation formula of the permeation grouting diffusion distance of the water-rich sand layer to obtain the calculation formula of the effective permeation grouting diffusion distance of the water-rich sand layer.

Description

Technical Field

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

[0002] Water-rich sand layers are strata with relatively high safety risks in underground engineering construction. Grouting technology has become one of the important construction measures for plugging groundwater and strengthening soft strata in underground engineering. Engineering practices have shown that when grouting sand strata with good injectability, the grout mainly spreads in a permeation manner. Under the action of pressure, the grout fills and penetrates into the pores of the sand layer, cementing the loose particles into a whole, thereby improving the strength and impermeability of the strata. At present, when determining the diffusion distance of permeation grouting in water-rich sand layers, a theoretical model of permeation grouting diffusion in water-rich sand layers is mostly established by comprehensively considering the rheological equation and equilibrium equation of the fluid, and the expression of the diffusion distance of permeation grouting is derived based on the theoretical model. However, the effect of grouting reinforcement and leakage stoppage depends on the strength and impermeability of the grouting stone body. Compared with the diffusion distance of permeation grouting, the effective reinforcement and leakage stoppage distance of permeation grouting is more valuable for practical engineering applications. Moreover, there are certain limitations in pure theoretical analysis. Theoretical derivations are often based on multiple basic assumptions, and the calculation results often have a large error compared with the actual values.

[0003] Therefore, proposing a scientific and reasonable method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layers has important reference value for guiding the design of actual engineering grouting schemes, optimizing grouting parameters, and improving the effect of grouting reinforcement and leakage stoppage. For this reason, a method for determining the effective diffusion distance formula of permeation 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 the effective diffusion distance formula of permeation grouting in water-rich sand layers.

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

[0006] Step S1, build a grouting model test platform for water-rich sand layers, and carry out Factor orthogonal model tests at different levels and obtain test data;

[0007] Step S2, use dimensional analysis theory to analyze the test data of the orthogonal model test, and derive the mathematical relationship of the actual diffusion distance of the grout;

[0008] Step S3: Take out the stone body formed in the grouting test platform, drill holes at different distances of the stone body to obtain the core of the stone body, measure and quantify the slurry filling rate in the core of the stone body, and establish a relationship between the slurry filling rate and the corresponding diffusion distance based on the slurry filling rate in the core of the stone body at different diffusion distances.

[0009] Step S4: Conduct penetration and uniaxial compression tests on the cores of the stone bodies at different diffusion distances to obtain test results, fit the test results to draw a three-dimensional diagram, find the mutation points from the three-dimensional diagram, clarify the slurry filling rate corresponding to the mutation points, 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 a reduction coefficient, and substitute the reduction coefficient into the calculation formula for the diffusion distance of permeation grouting in water-rich sand layers to obtain the calculation formula for the effective diffusion distance of permeation grouting in water-rich sand layers.

[0010] Preferably, the step S1 includes:

[0011] Step S11: Build a grouting model test platform for water-rich sand layers;

[0012] Step S12: Design Factor Orthogonal model tests at different levels, and through the grouting model test platform for water-rich sand layers, conduct grouting tests in sequence according to the designed orthogonal model tests, and record the actual diffusion distance of the slurry in the test after each group of tests. .

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

[0014] The grouting test device is used to simulate the water-rich sand layer, and the grouting system is connected to one end of the grouting test device, and the grouting system is used to inject slurry into the simulated water-rich sand layer;

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

[0016] The acquisition end of the data acquisition system 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 the step S12, The factors are grouting pressure , grouting volume and permeability , Select 4 levels.

[0018] Preferably, step S2 includes:

[0019] Step S21, deriving the mathematical relationship of the actual diffusion distance of the slurry according to the dimensional analysis theory :

[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 are constants to be determined;

[0022] Step S22, according to the data of the actual diffusion distance of the slurry in each group of tests, using data processing software to fit and solve the constants , , and , and substituting the obtained , , and into and improving the mathematical relationship of the actual diffusion distance of the slurry.

[0023] Preferably, step S3 includes:

[0024] Step S31, after the grouting test is completed, conduct normal temperature curing on the stone body formed in the grouting test platform for 7 days. After the curing is completed, divide the cross-section along the central axis of the stone body, and the distance between each cross-section is equal. Plan 9 sampling positions on each cross-section, and conduct coring operations in sequence according to the divided sampling positions to obtain the stone body cores. Grind each stone body core into a cylinder with a unified specification, and arrange the ground stone body cores according to the sampling positions. All the stone body cores in the same row form an inspection group;

[0025] Step S32, select the inspection group located on the central axis of the stone body, and use a scanning electron microscope and a low-field nuclear magnetic resonance micro-observation device to sequentially test and quantify the slurry filling rate in the voids of each cross-section of the stone body core in an inspection group. Take the slurry filling rate of the stone body core and the sampling position of the stone body core as a coordinate point. According to all the coordinate points in an inspection group, establish the relationship between the slurry filling rate and the corresponding diffusion distance of the slurry:

[0026] 。

[0027] Preferably, in the step S4, the reduction coefficient includes the reduction coefficient of the effective reinforcement distance and the reduction coefficient of the effective plugging distance , and the calculation formula for the effective diffusion distance of permeation grouting in water-rich sand layers includes the effective reinforcement distance of permeation grouting diffusion in water-rich sand layers and the effective plugging distance of permeation grouting diffusion in water-rich sand layers 。

[0028] Preferably, the step S4 includes:

[0029] Step S41, select a test group located on the adjacent side of the central axis of the stone body, conduct uniaxial compression tests on the stone core in the test group in sequence and obtain the compressive strength data of each stone core in the test group, and conduct fitting analysis on all the obtained compressive strength data;

[0030] Step S42, draw a three-dimensional diagram of compressive strength, filling rate and diffusion distance according to the fitting analysis results, find the compressive strength mutation point from the three-dimensional diagram, and clarify the slurry filling rate corresponding to the compressive strength mutation point ;

[0031] Step S43, substitute the slurry filling rate into the relational expression of the slurry filling rate and the corresponding diffusion distance of the slurry , and the corresponding diffusion distance corresponding to the slurry filling rate is the effective reinforcement distance , compare the maximum value of the effective reinforcement distance with the actual diffusion distance of the slurry, and the ratio is the reduction coefficient of the effective reinforcement distance ;

[0032] Step S44, introduce the reduction coefficient of the effective reinforcement distance into the calculation formula of the actual diffusion distance of the slurry, and obtain the calculation formula for the effective reinforcement distance of permeation grouting in water-rich sand layers:

[0033] ;

[0034] Step S45, select another test group located on the adjacent side of the central axis of the stone body, conduct water infiltration tests on the stone core in the test group in sequence and obtain the permeability data of each stone core in the test group, and conduct fitting analysis on the permeability data of different cross-sectional samples obtained from the water infiltration test;

[0035] Step S46: Draw a three-dimensional diagram of permeability, filling rate, and diffusion distance based on the fitting analysis results, find the permeability mutation points from the three-dimensional diagram, and clarify the corresponding slurry filling rate of the permeability mutation points ;

[0036] Step S47: Substitute the slurry filling rate into the relational expression of the slurry filling rate and the corresponding diffusion distance of the slurry. The corresponding diffusion distance corresponding to the slurry filling rate is the effective leakage plugging distance . Compare the maximum value of the effective leakage plugging distance with the actual diffusion distance of the slurry. The ratio is the reduction coefficient of the effective leakage plugging distance :

[0037] Step S48: Introduce the reduction coefficient of the effective leakage plugging distance into the calculation formula of the actual diffusion distance of the slurry to obtain the calculation formula of the effective leakage plugging distance for permeation grouting in water-rich sand layers:

[0038] .

[0039] The beneficial effects of the present invention compared with the prior art are as follows:

[0040] 1. The present invention sets up a grouting model test platform for water-rich sand layers. Through multi-factor orthogonal test research on grouting pressure, grouting volume, permeability, etc., based on the dimensional analysis theory and combined with the model test results, the calculation formula for the diffusion distance of permeation grouting in water-rich sand layers is derived. Based on the core-taking test at different diffusion distances in the model test, the corresponding relationship between the slurry filling rate and the diffusion distance is constructed. The calculation formula for the effective reinforcement and leakage plugging distance is derived from the performance improvement and filling efficiency. The calculation formula for the effective reinforcement and leakage plugging distance can guide the design of the actual engineering grouting plan, optimize the grouting parameters, and achieve the purpose of improving the grouting reinforcement and leakage plugging effect. Brief Description of the Drawings

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

[0042] Figure 2 is a schematic diagram of the grouting model test platform for water-rich sand layers in an embodiment of the present invention;

[0043] Figure 3 is the slurry filling rate and diffusion distance of the grouting model test for water-rich sand layers in an embodiment of the present invention , and Schematic diagram of the relationship;

[0044] Figure 4 It is a schematic diagram of the core-taking position of the grouting model test stone body in the water-rich sand layer in the embodiment of the present invention;

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

[0046] Figure 6 It is a schematic diagram of the relationship among the permeability, filling rate and diffusion distance in the 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 oil cylinder; 18. Hydraulic servo controller; 2. Grouting system; 21. Grouting pump; 22. A liquid storage tank; 23. B liquid storage tank; 24. Grout pipeline; 3. Simulated 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. Seepage pressure sensor; 43. Resistivity sensor; 44. Flat film pressure transmitter; 45. Grouting pressure sensor; 46. PC. Specific implementation mode

[0049] The following further elaborates the present invention in combination with the accompanying drawings and embodiments for the above and other technical features and advantages of the present invention. However, the following embodiments are only the embodiments of the present invention and not all of them.

[0050] Embodiment:

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

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

[0053] The grouting test device 1 is used to simulate the 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 oil 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 arranged on one side inside the reaction frame 11. One end of the grouting test chamber 12 abuts against one side of the inner wall of the reaction frame 11. Two groups of permeable stones 13 are respectively filled at both ends inside the grouting test chamber 12. The water-rich sand layer 14 is filled at 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 sleeved on the other end of the grouting test chamber 12. The loading oil cylinder 17 is arranged on the other side inside the reaction frame 11. The base of the loading oil cylinder 17 abuts against the inner wall of the reaction frame 11. The movable end of the loading oil cylinder 17 abuts against the loading plate 16. The hydraulic servo controller 18 is connected to the loading oil cylinder 17 through a hydraulic pipeline. During the test, the hydraulic servo controller 18 supplies hydraulic pressure to the loading oil cylinder 17 through the hydraulic pipeline. The loading oil cylinder 17 works to push the loading plate 16 to move horizontally along the grouting test chamber 12. The grouting test chamber 12 simulates the pressure environment by squeezing the permeable stone 13 and the water-rich sand layer 14 during the horizontal movement;

[0055] The grouting system 2 is connected to one end of the grouting test device 1. The grouting system 2 is used to inject slurry into the simulated water-rich sand layer. The grouting system 2 includes a grouting pump 21, an A liquid storage tank 22, a B liquid storage tank 23, and a slurry transmission pipeline 24. The grouting pump 21 is arranged outside the reaction frame 11. The A liquid storage tank 22 and the B liquid storage tank 23 are connected to the input end of the grouting pump 21 through a feed pipeline. The two ends of the slurry transmission 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] When grouting, the grouting pump 21 pumps out and mixes the slurries in the A liquid storage tank 22 and the B liquid storage tank 23, and then injects them into the water-rich sand layer 14 through the slurry transmission pipeline 24 and the slurry control valve 15;

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

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

[0059] The acquisition 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 seepage 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 seepage 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 seepage pressure sensor 42 is buried at the central position of the water-rich sand layer 14, and the end of the resistivity sensor 43 is buried at the edge position 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 seepage 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 through the data acquisition instrument 41;

[0060] During the test, the seepage pressure sensor 42 collects seepage pressure data, and the resistivity sensor 43 collects resistivity change data. The resistivity change can reflect the diffusion distance of the slurry, so as to obtain the actual diffusion distance ;

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

[0062] Relying on the water-rich sand layer grouting model test platform, an orthogonal model test of 3 factors and 4 levels is carried out. The 3 factors are grouting pressure P, grouting volume Q, and permeability K;

[0063] The 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] The permeability K is 0.01 、0.05 、0.1 and 0.15 four levels;

[0066] Form the orthogonal model test design table shown in Table 1.

[0067] Table 1. Orthogonal model test design table

[0068] Number #timg# / MPa #timg# / #timg# #timg# / #timg# 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] Through the grouting model test platform for water-rich sand layer, grouting tests were carried out in sequence according to the data in Table 1, and the actual diffusion distance of the grout in the test was recorded after each group of tests ;

[0070] The recorded results were summarized to form the statistical table of the actual diffusion distance of the grout shown in Table 2 Statistical table

[0071] Table 2. Statistical table of the actual diffusion distance of the grout Statistical table

[0072] Number #timg# / m 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 the dimensional analysis theory to analyze the data content in Table 1 and Table 2, the mathematical relationship of the actual diffusion distance of the grout was deduced :

[0074] ;

[0075] In the formula is the actual diffusion distance of the grout, is the grouting pressure, is the grouting volume, is the permeability, , , and are the constants to be determined;

[0076] According to the statistical data of the actual diffusion distance of the grout in Table 2 , the constants , , and were fitted and solved using the data processing software Origin. The obtained , , and were substituted to obtain the improved mathematical relationship of the actual diffusion distance of the grout :

[0077] ;

[0078] After the grouting test, the formed stone body in the grouting test platform was cured at room temperature for 7 days, as Figure 4As shown, after the curing is completed, a cross-section is divided along the central axis of the stone body, and the spacing between each cross-section is equal. Nine sampling positions are planned for each cross-section, and coring operations are sequentially carried out according to the divided sampling positions to obtain the stone body cores. Each stone body core is polished into a cylinder with a unified specification, and the polished stone body cores are arranged according to the sampling positions. All the stone body cores in the same row form a test group;

[0079] Select the test group located on the central axis of the stone body, and use a scanning electron microscope and a low-field nuclear magnetic resonance micro-observation device to sequentially test and quantify the slurry filling rate in the cross-section voids of each stone body core in a test group , and take the slurry filling rate of the stone body core and the sampling position of the stone body core as a coordinate point. According to all the coordinate points in a test group, establish the relationship between the slurry filling rate and the corresponding diffusion distance of the slurry :

[0080]

[0081] Carry out penetration and uniaxial compression tests on the stone body cores at different diffusion distances to obtain test results, fit the test results to draw a three-dimensional diagram, find the mutation points from the three-dimensional diagram, clarify the slurry filling rate corresponding to the mutation points, and 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. The reduction coefficient includes the reduction coefficient of the effective reinforcement distance and the reduction coefficient of the effective plugging distance ;

[0082] Substitute the reduction coefficient into the calculation formula for the diffusion distance of permeation grouting in water-rich sand layers to obtain the calculation formula for the effective diffusion distance of permeation grouting in water-rich sand layers. The calculation formula for the effective diffusion distance of permeation grouting in water-rich sand layers includes the effective reinforcement distance of permeation grouting in water-rich sand layers and the effective plugging distance of permeation grouting in water-rich sand layers ;

[0083] Select a test group located adjacent to the central axis of the stone body, and sequentially carry out uniaxial compression tests on each stone body core in each test group to obtain the compressive strength data of the stone body cores, and conduct fitting analysis on the obtained compressive strength data;

[0084] As Figure 5 shown, draw a three-dimensional diagram of compressive strength, filling rate, and diffusion distance according to the fitting analysis results, find the compressive strength mutation points from the three-dimensional diagram, arbitrarily select a compressive strength mutation point, and clarify the slurry filling rate corresponding to the selected compressive strength mutation point ;

[0085] Bring the slurry filling rate into the relationship between the slurry filling rate and the corresponding diffusion distance of the slurry . In the relationship, the corresponding diffusion distance corresponding to the slurry filling rate is the effective diffusion reinforcement distance . Compare the maximum value of the effective diffusion reinforcement distance with the actual diffusion distance of the slurry . The ratio is the reduction coefficient of the effective reinforcement distance ;

[0086] Introduce the reduction coefficient of the effective reinforcement distance into the calculation formula of the actual diffusion distance of the slurry to obtain the calculation formula for the effective diffusion reinforcement distance of permeation grouting in water-rich sand layers:

[0087] ;

[0088] Select another test group adjacent to the central axis of the stone body. Conduct infiltration waterlogging tests on the stone core in the test group in sequence and obtain the permeability data of each stone core in the test group. Conduct fitting analysis on the permeability data of different cross-sectional specimens obtained from the infiltration waterlogging tests;

[0089] As Figure 6 shown, draw a three-dimensional diagram of permeability, filling rate, and diffusion distance based on the fitting analysis results. Find the permeability mutation point from the three-dimensional diagram. Arbitrarily select a permeability mutation point and determine the slurry filling rate corresponding to the selected permeability mutation point;

[0090] Bring the slurry filling rate into the relationship between the slurry filling rate and the corresponding diffusion distance of the slurry . The corresponding diffusion distance corresponding to the slurry filling rate is the effective diffusion leakage-blocking distance . Compare the maximum value of the effective diffusion leakage-blocking distance with the actual diffusion distance of the slurry . The ratio is the reduction coefficient of the effective leakage-blocking distance ;

[0091] Introduce the reduction coefficient of the effective leakage-blocking distance into the calculation formula of the actual diffusion distance of the slurry to obtain the calculation formula for the effective diffusion leakage-blocking distance of permeation grouting in water-rich sand layers:

[0092] 。

[0093] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. Method for determining effective distance formula of permeation grouting diffusion in water-rich sand layer, characterized in that: It includes the following steps: Step S1, build a grouting model test platform for water-rich sand layers, and carry out factor orthogonal model tests at different levels and obtain test data; Step S2: Analyze the test data of the orthogonal model test by using the dimensional analysis theory, and derive the mathematical relationship of the actual diffusion distance of the grout. Step S3: Take out the stone body formed in the grouting test platform, drill holes at different distances of the stone body to obtain the stone core of the stone body, measure and quantify the grout filling rate in the stone core of the stone body, and construct the relationship between the grout filling rate and the corresponding diffusion distance according to the grout filling rate in the stone core of the stone body at different diffusion distances. Step S4: Conduct penetration and uniaxial compression tests on the stone cores of the stone body at different diffusion distances to obtain test results, fit the test results to draw a three-dimensional diagram, find the mutation points from the three-dimensional diagram, clarify the grout filling rate corresponding to the mutation points, obtain the corresponding diffusion distance through the relationship between the grout filling rate and the corresponding diffusion distance, compare the corresponding diffusion distance with the actual diffusion distance of the grout to obtain the reduction coefficient, and substitute the reduction coefficient into the calculation formula of the diffusion distance of permeation grouting in the water-rich sand layer to obtain the calculation formula of the effective diffusion distance of permeation grouting in the water-rich sand layer.

2. The method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layer according to claim 1, characterized in that The said Step S1 includes: Step S11: Build a grouting model test platform for the water-rich sand layer. Step S12, design factor orthogonal model test of levels, through the grouting model test platform for water-rich sand layer, conduct grouting tests in sequence according to the designed orthogonal model test, and record the actual diffusion distance of the slurry in the test after each group of tests .

3. The method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layer according to claim 2, characterized in that, In the said Step S11, the grouting model test platform for the water-rich sand layer includes a grouting test device, a grouting system, an artificial groundwater pressurization system, and a data acquisition system. The said grouting test device is used to simulate the water-rich sand layer. The grouting system is connected to one end of the grouting test device, and the grouting system is used to inject grout into the simulated water-rich sand layer. The said artificial groundwater pressurization system is respectively connected to both ends of the grouting test device, and the artificial groundwater pressurization system is used to maintain the dynamic transfer of water bodies in the simulated water-rich sand layer during the grouting process. The acquisition end of the said data acquisition system 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 distance formula of permeation grouting diffusion in a water-rich sand layer according to claim 2, characterized in that, In the said step S12, the factors are grouting pressure , grouting volume and permeability , and 4 levels are selected.

5. The method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layer according to claim 1, characterized in that, The said Step S2 includes: Step S21, derive the mathematical relationship of the actual diffusion distance of the slurry according to the dimensional analysis theory as follows: ； In the formula is the actual diffusion distance of the slurry, is the grouting pressure, is the grouting volume, is the permeability, , , and are constants to be determined; Step S22, according to the actual diffusion distance of the slurry in each group of tests data, use data processing software to fit and solve the constants , , and , and substitute the obtained , , and into and improve the mathematical relationship of the actual diffusion distance of the slurry .

6. The method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layer according to claim 1, characterized in that The said Step S3 includes: Step S31: After the grouting test is completed, conduct normal temperature curing on the stone body formed in the grouting test platform for 7 days. After the curing is completed, divide the cross-section along the central axis of the stone body. The distance between each cross-section is equal. Plan 9 sampling positions in each cross-section, and carry out coring operations in sequence according to the divided sampling positions to obtain the stone core of the stone body. Grind each stone core of the stone body into a cylinder with a unified specification. Arrange the ground stone cores of the stone body according to the sampling positions. All the stone cores of the stone body in the same row form a test group. Step S32: Select an inspection group located on the central axis of the stone body, and use a scanning electron microscope and a low-field nuclear magnetic resonance micro-observation device to sequentially test and quantify the slurry filling rate in the voids of each cross-section of the stone core in an inspection group. , and take the slurry filling rate of the stone core and the sampling position of the stone core as a coordinate point. Based on all the coordinate points in an inspection group, establish the relationship between the slurry filling rate and the corresponding diffusion distance of the slurry : 。 7. The method for determining the effective diffusion distance formula of permeation grouting in water-rich sand layer according to claim 1, characterized in that, In the said step S4, the reduction coefficient includes the reduction coefficient of the effective reinforcement distance and the reduction coefficient of the effective plugging distance . The calculation formula for the effective diffusion distance of permeation grouting in water-rich sand layer includes the effective reinforcement distance of permeation grouting diffusion in water-rich sand layer and the effective plugging distance of permeation grouting diffusion in water-rich sand layer .

8. The method for determining the effective distance formula of permeation grouting diffusion in a water-rich sand layer according to claim 7, characterized in that, The said Step S4 includes: Step S41: Select a test group adjacent to the central axis of the stone body, conduct uniaxial compression tests on the stone cores of the stone body in the test group in sequence, and obtain the compressive strength data of each stone core in the test group. Conduct fitting analysis on all the obtained compressive strength data. Step S42: Draw a three-dimensional graph of the compressive strength, filling rate, and diffusion distance based on the fitting analysis results, find the compressive strength mutation points from the three-dimensional graph, and identify the slurry filling rate corresponding to the compressive strength mutation points ; Step S43, bring the slurry filling rate into the relational expression of the slurry filling rate and the corresponding diffusion distance of the slurry . The corresponding diffusion distance corresponding to the slurry filling rate is the effective diffusion reinforcement distance . Compare the effective diffusion reinforcement distance with the maximum value of the actual diffusion distance of the slurry . The ratio is the reduction coefficient of the effective reinforcement distance ; Step S44, introduce a reduction coefficient of the effective reinforcement distance into the calculation formula for the actual diffusion distance of the slurry to obtain the calculation formula for the effective reinforcement distance of diffusion in permeation grouting for water-rich sand layers as follows: ​ ； Step S45: Select another test group adjacent to the central axis of the stone body, conduct penetration water flooding tests on the stone cores of the stone body in the test group in sequence, and obtain the permeability data of each stone core in the test group. Conduct fitting analysis on the permeability data of different cross-section samples obtained from the penetration 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 points from the three-dimensional graph, and clarify the slurry filling rate corresponding to the permeability mutation points ; Step S47, bring the slurry filling rate into the relational expression of the slurry filling rate and the corresponding diffusion distance of the slurry . The corresponding diffusion distance corresponding to the slurry filling rate is the effective diffusion plugging distance . Compare the effective diffusion plugging distance with the maximum value of the actual diffusion distance of the slurry . The ratio is the reduction coefficient of the effective plugging distance : Step S48, introduce a reduction coefficient of the effective plugging distance into the calculation formula for the actual diffusion distance of the slurry to obtain the calculation formula for the effective plugging and diffusion distance of permeation grouting in water-rich sand layers as follows: ​ 。

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