Multidirectional spatial distribution pre-estimation method for inclined fracture viscosity change slurry pressure

Abstract

The invention provides a multidirectional spatial distribution pre-estimation method for inclined fracture viscous variable slurry pressure, and belongs to the field of safe and green mining of mines, and the multidirectional spatial distribution pre-estimation method comprises the following steps: S1, introducing a slurry diffusion radius, a diffusion length calculation section number and a direction angle section number; s2, calculating a unit radius and a unit angle; s3, the slurry diffusion radius ri + 1, k and the average diffusion radius # imgabs0 # are calculated; S4, the average diffusion speed # imgabs1 # time delta ti, k and the total time T (i, k) are calculated; s5, the average slurry viscosity # imgabs2 # is calculated; S6, the grouting pressure gradient delta Pi, k is obtained; s7, the grouting pressure Pi, k in the fracture is calculated; s8, progressively increasing the diffusion radius, repeating the steps S1-S7, and completing the estimation of the upper pressure at the direction angle k [delta] w; and S9, progressively increasing the direction angle, repeating the steps S1-S7, completing pressure estimation on the direction angle (k + 1) delta w, and completing pressure estimation on the whole fracture surface.

Description

Technical Field

[0001] The invention relates to the technical field of safe and green mining of mines, and in particular to a method for estimating the diffusion and grouting pressure of rock mass grouting slurry in underground engineering. Background Art

[0002] In recent years, disasters and accidents faced by mineral resource mining have occurred frequently. The reason is that the engineering rock mass will produce weak structures such as pores and cracks due to changes in the external environment, and the performance of the main body is much lower than the initial complete structure. For this reason, people have applied a method that meets engineering needs, namely grouting, which is essentially to prepare cement and other materials into slurry, and use pressure-feeding equipment to inject it into the cracks of the rock mass to make it diffuse, gel or solidify, so as to achieve the purpose of strengthening the rock mass or preventing seepage and plugging leaks.

[0003] While grouting in fractured rock (fracture grouting and splitting grouting) is largely uncontrollable grouting, we can try to use known rock mechanics parameters, slurry performance indicators, etc. to establish an effective grouting diffusion model to accurately describe the slurry migration law and estimate the diffusion range of fractured rock grouting. For example, the Chinese invention patent application with publication number CN108487918A, "Design method for grouting treatment of fractured rock water in surrounding rock of tunnels and underground engineering", obtains the quantitative relationship between grouting pressure, grouting rate and slurry diffusion distance through the slurry diffusion theoretical equation. The grouting pressure is based on the grouting pressure theoretical value P in step D. g The formula is calculated using the viscosity and crack width when the radius R is reached, but the formula itself is inaccurate.

[0004] At present, people tend to ignore the multi-angle cross and non-smooth characteristics of rock mass cracks in geological rock formations, resulting in certain deviations in the estimated grouting parameters; at the same time, people tend to ignore the viscosity characteristics of the slurry, resulting in insufficient estimation of the grouting pressure and grouting diffusion range, which in turn leads to material waste, insufficient grouting and other consequences. Characterizing rock mass cracks and slurry viscosity to estimate slurry diffusion has become a problem that must be solved for grouting disaster prevention and control.

[0005] Therefore, there is an urgent need for a computable and easy-to-implement estimation method to evaluate the diffusion range. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to estimate the grouting pressure under complex working conditions such as inclined cracks and viscous grouting slurries, so as to solve many problems existing in the rock grouting process, such as material waste, insufficient grouting, and design difficulties.

[0007] The present invention solves the above technical problems through the following technical solutions: a method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures, comprising the following steps:

[0008] S1, the diffusion radius L of the slurry required to be introduced into the crack, the average gap width b, the tilt angle β of the inclined crack, the initial viscosity μ0, the viscosity coefficient η, the grouting hole diameter r0, the external pressure P0, the grouting flow rate q, and the number of diffusion length calculation segments n and the number of direction angle segments m are given;

[0009] S2, calculate the unit radius Δr and the unit angle Δw;

[0010] S3. Define the initial pressure as the external pressure P0, the initial diffusion radius as the grouting hole diameter r0, and calculate the slurry diffusion radius r under the same direction angle kΔw. i+1,k and the average diffusion radius

[0011] S4. Based on the mass balance law, the average diffusion velocity of different diffusion radii under the same direction angle kΔw and unit radius Δr is calculated according to the crack width. Calculate the time Δt required for the diffusion radius to reach the unit radius Δr i,k , the total time t(i,k) after diffusion over a certain distance;

[0012] S5. Calculate the average slurry viscosity that changes with grouting time at the same direction angle kΔw

[0013] S6. According to the pressure gradient control equation, the grouting pressure gradient ΔP of the unit radius Δr is obtained when the direction angle is kΔw. i,k ;

[0014] S7, calculate the direction angle kΔw and the diffusion radius r i,k The grouting pressure P in the crack i,k ;

[0015] S8, increasing diffusion radius r at the same direction angle kΔw i,k , repeat S1-S7 until i=n, ​​and complete the estimation of grouting pressure at the direction angle kΔw;

[0016] S9, increasing direction angle, increasing diffusion radius r at the same direction angle (k+1)Δw i,k , repeat S1-S7 until i=n, ​​complete the estimation of the grouting pressure at the direction angle of (k+1)Δw, until the estimation of the grouting pressure of the entire fracture surface is completed.

[0017] Preferably, the unit radius Δr and the unit angle Δw in step S2 are calculated by the following formula:

[0018] Δr=L / n,Δw=2π / m, where L is the slurry diffusion radius, n is the number of diffusion length calculation segments, and m is the number of directional angle segments.

[0019] Preferably, the slurry diffusion radius r in step S3 i+1,k and the average diffusion radius Calculated by the following formula:

[0020]

[0021] Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, r i,k is the slurry diffusion radius at the direction angle kΔw, where the slurry diffusion distance reaches iΔr, and Δr is the unit radius.

[0022] Preferably, the average diffusion rate in step S4 is The time Δt required for the diffusion radius to reach the unit radius Δr i,k , the total time T(i,k) after diffusion over a certain distance is calculated by the following formula:

[0023]

[0024] in, is the crack width, b is the average crack width, JRC is the rated constant commonly used in rock engineering to characterize crack roughness, j = 0-n.

[0025] Preferably, the average slurry viscosity in step S5 is Calculated by the following formula:

[0026]

[0027] Among them, μ i,k is the viscosity of the slurry with a diffusion radius of iΔr and a direction angle of kΔw, μ i-1,k is the viscosity of the slurry with a diffusion radius of (i-1)Δr and a direction angle of kΔw, μ i,k =μ0+ηT(i,k),v i-1,k =μ0+ηT(i-1,k), after rearrangement we can get:

[0028]

[0029] Preferably, the grouting pressure gradient ΔP in step S6 i,k Calculated by the following formula:

[0030]

[0031] Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, is the average slurry viscosity, q is the grouting flow rate, is the crack width, ρ is the slurry density, g is the free acceleration, Δw is the unit angle, k=0-m, m is the number of directional angle segments, β is the tilt angle of the inclined crack, and Δr is the unit radius.

[0032] Preferably, the grouting pressure P in the crack in step S7 is i,k Calculated by the following formula:

[0033]

[0034] Among them, P i-1,k The direction angle is kΔw and the diffusion radius is r i-1,k The grouting pressure in the crack at that time.

[0035] Preferably, the slurry will present a circular diffusion pattern in each unit direction within the spatial crack, the slurry increases in the diffusion direction by Δw and is represented by a variable k, k=0-m, and the slurry increases in the diffusion distance by Δr and is represented by a variable i, i=0-n.

[0036] Preferably, the average gap width b is obtained in field engineering by conventionally measuring rock permeability and calculating using the conventional Darcy formula.

[0037] Preferably, the viscosity coefficient η is obtained by: measuring the viscosity of the grouting slurry at different times by a viscometer, obtaining the change of the grouting slurry over time, and thus determining the viscosity coefficient η of the grouting slurry.

[0038] The advantages provided by the present invention are: through spatial unitization calculation, spatial unitization is used to characterize time unitization, and the viscosity change of slurry, the width change of inclined cracks, and the gravity change of inclination angle within unit time are taken into account in the estimated calculation of grouting pressure, so that the estimation of grouting pressure is more in line with the problems of unevenness and inclination of actual crack surfaces, and the accuracy of grouting pressure estimation is improved, and the depth calculation of slurry diffusion pressure and diffusion radius under complex working conditions such as inclined cracks and viscous grouting slurry is realized, the rationality of grouting parameter design is improved, the waste of grouting materials in grouting projects is avoided, the grouting cost is reduced, and effective data can be provided for the design of grouting projects in the mining field, thereby improving the grouting efficiency and utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a method for estimating the multi-directional spatial distribution of the viscous slurry pressure in an inclined fracture provided in Example 1 of the present invention;

[0040] Figure 2 A schematic diagram of a method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures provided in Example 1 of the present invention;

[0041] In the figure: 1 grouting hole, 2 inclined fracture, 3 fan-shaped annular unit. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is clearly and completely described below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] like Figure 1 As shown, this embodiment provides a method for estimating the multi-directional spatial distribution of the viscous slurry pressure in an inclined fracture, comprising the following steps:

[0045] Step 1: According to the actual situation of the grouting project, determine the required slurry diffusion radius L, average gap width b, inclined crack inclination angle β, initial viscosity μ0, viscosity coefficient η, grouting hole diameter r0, external pressure P0, and grouting flow rate q, and give the number of diffusion length calculation segments n and the number of direction angle segments m by comprehensively considering the complexity of the calculation process.

[0046] In actual work, for different fissures, the slurry diffusion range to be achieved through grouting is different, and the slurry diffusion radius L reflects the slurry diffusion range. The average gap width b can be obtained by conventionally measuring the rock permeability and calculating the conventional Darcy formula in field engineering. The inclination angle β of the inclined fissure is generally measured by drilling and coring, and the initial viscosity μ0 can be directly obtained by a viscometer indoors. When the selected grouting slurry is determined, the viscosity coefficient η can be determined. The viscosity of the grouting slurry at different times can be measured by the viscometer, and the change of the grouting slurry over time can be obtained, so that the viscosity coefficient η of the grouting slurry can be determined. The aperture r0 of the grouting hole has been designed during the grouting project construction process, and the design value can be directly used. The external pressure P0 refers to the water pressure in the rock formation. Since the role of grouting is to block water and prevent seepage in the fissure, and the flow of cement and other slurries in the water environment will be affected by the water pressure, the present invention takes into account the external pressure P0, which is generally measured by drilling and other methods before the mine is effectively mined, and the value is directly used during grouting. The grouting flow rate q is generally determined based on the selected pressure delivery equipment and traditional experience values. The selected pressure delivery equipment will have a limited flow range.

[0047] Step 2: Use the diffusion length to calculate the number of segments n and the direction angle segments m to calculate the unit radius Δr and the unit angle Δw.

[0048] Δr=L / n, Δw=2π / m, where L is the slurry diffusion radius.

[0049] See also Figure 2For the inclined fissure 2 with a tilt angle β, if you want to achieve a good grouting effect through grouting, it must be based on a preset grouting pressure. Generally, a certain flow rate of cement or other slurry is injected into the rock formation through a grouting pump. At this time, the grouting pressure must be controlled to achieve efficient slurry diffusion, that is, to achieve a good anti-seepage and plugging effect for the inclined fissure 2. At this time, the corresponding slurry diffusion radius is L. The slurry diffusion radius L here starts from the grouting hole. Considering the complexity of the calculation process, the slurry diffusion radius L is divided into n diffusion length calculation segments. The length of each fan-shaped annular unit 3 calculation segment Δr=L / n, and the angle 2π of the circular diffusion direction can be divided into m calculation segments. The angle calculated for each fan-shaped annular unit 3 can be expressed as Δw=2π / m. Then the boundary conditions in the diffusion direction satisfy the gradually increasing pattern of Δw, 2Δw, ..., kΔw, ..., (m-1)Δw, mΔw, and the boundary conditions in the diffusion distance satisfy the gradually increasing pattern of Δr, 2Δr, ..., iΔr, ..., (n-1)Δr, nΔr, where k = 0-m, i = 0-n.

[0050] Step 3: Enter the spatial distribution estimation calculation, define the initial pressure as the external pressure P0, the initial diffusion radius as the grouting hole diameter r0, and the slurry will show a circular diffusion pattern in each unit direction in the spatial crack. The slurry increases in the diffusion direction by Δw and is represented by the variable k, k = 0-m. The slurry increases in the diffusion distance by Δr and is represented by the variable i, i = 0-n. Calculate the slurry diffusion radius r at the same direction angle kΔw i+1,k and the average diffusion radius

[0051]

[0052] Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, r i,k is the slurry diffusion radius at the direction angle kΔw, and the slurry diffusion distance reaches iΔr, where Δr is the unit radius.

[0053] Step 4: Based on the mass balance law, calculate the average diffusion velocity of different diffusion radii under the same direction angle kΔw and unit radius Δr according to the crack width Thus, the time Δt required for the diffusion radius to reach the unit radius Δr is calculated i,k , the total time after diffusion for a certain distance T(i,k):

[0054] See also Figure 2 , within each unit radius Δr, it is a disc-shaped diffusion, so the volume of slurry in the unit radius Δr per unit time is the volume pumped in by the grouting pump, that is, the flow rate, which can be obtained:

[0055]

[0056] in, is the crack width, b is the average crack width, JRC is the rated constant commonly used in rock engineering to characterize crack roughness, j = 0-n.

[0057] Step 5: Considering the viscosity variation characteristics of the slurry flowing in the cracks and its influence on the grouting pressure, calculate the average slurry viscosity that changes with grouting time at the same direction angle kΔw

[0058] The viscosity variation characteristic refers to the time correlation of the viscosity of the slurry in the crack, the existence of a correlation coefficient, and the control of the viscosity equation. The viscosity of the slurry with a diffusion radius of iΔr and a direction angle of kΔw is μ i,k It can be expressed as:

[0059] μ i,k =μ0+ηT(i,k),

[0060] Average slurry viscosity

[0061]

[0062] μ i-1,k is the viscosity of the slurry with a diffusion radius of (i-1)Δr and a direction angle of kΔw, μ i-1,k =μ0+ηT(i-1,k).

[0063] After sorting, we can get:

[0064]

[0065] Step 6: Under the condition that the average gap width is b, the pressure gradient control equation with a diffusion radius of R can be obtained by the grouting flow rate q and the slurry viscosity μ in the grouting area:

[0066]

[0067] According to the pressure gradient control equation, the grouting pressure gradient ΔP of the unit radius Δr can be obtained when the direction angle is kΔw. i,k :

[0068]

[0069] Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, is the average slurry viscosity, q is the grouting flow rate, is the crack width, ρ is the slurry density, g is the free acceleration, Δw is the unit angle, k=0-m, m is the number of directional angle segments, β is the tilt angle of the inclined crack, and Δr is the unit radius.

[0070] Step 7: Calculate the direction angle kΔw and the diffusion radius r i,k The grouting pressure P in the crack i,k :

[0071]

[0072] Among them, P i-1,k The direction angle is kΔw and the diffusion radius is r i-1,k The grouting pressure in the crack at that time.

[0073] Step 8: Increase the diffusion radius r at the same direction angle kΔw i,k , for example, the diffusion radius reaches r i+1,k , repeat the calculation process of steps 1-7 above until i=n, ​​and complete the estimation of the grouting pressure at the direction angle kΔw.

[0074] Step 9: Increase the direction angle. For example, if the direction angle is (k+1)Δw, increase the diffusion radius r at the same direction angle (k+1)Δw. i,k , for example, the diffusion radius reaches r i+1,k , repeat the calculation process of steps 1-7 above until i=n, ​​complete the estimation of the grouting pressure at the direction angle of (k+1)Δw, and complete the estimation of the grouting pressure of the entire fracture surface.

[0075] How it works: See Figure 2, the inclination angle of the inclined fissure 2 is β, the aperture of the grouting hole 1 is r0, and according to the actual situation of the grouting project, the required slurry diffusion radius is determined to be L, and the slurry is injected into the grouting hole 1 using pressure equipment. In theory, the slurry viscosity will gradually increase with the injection time of the pump station. The increase in slurry viscosity will cause the increase in pumping pressure, and the diffusion range of the slurry depends on the pumping pressure. Therefore, there will be an increase in the viscosity of the slurry during the actual pumping process, resulting in an increase in the required pressure. The phenomenon of increased slurry viscosity is often ignored in existing grouting work, which will cause insufficient estimation of the pumping pressure, resulting in a decrease in the diffusion range of the grouting slurry, and then causing problems such as material waste or insufficient grouting. In addition, the cracks are spatially distributed and are non-planar with ups and downs, which will also affect the slurry flow and thus affect the grouting pressure. The present invention aims to address the problem that the grouting pressure and the grouting diffusion range are insufficiently estimated due to the neglect of the change in slurry viscosity and the inclination angle of the inclined cracks during existing grouting. The present invention divides the slurry diffusion radius L into n diffusion length calculation segments through spatial unit calculation, and the angle 2π in the circular diffusion direction can be divided into m calculation segments. Then, the length of each fan-shaped annular unit 3 calculation segment Δr=L / n, and the angle calculated for each fan-shaped annular unit 3 can be expressed as Δw=2π / m. Considering that the slurry will present a circular diffusion pattern in each unit direction within the spatial crack, it can be seen that the slurry increases one by one in the diffusion direction according to Δw, 2Δw, ..., kΔw, ..., (m-1)Δw, mΔw, and increases one by one in the diffusion distance according to Δr, 2Δr, ..., iΔr, ..., (n-1)Δr, nΔr, where k=0-m, i=0-n, and Figure 2 For example, line I is an analysis boundary with a direction angle of kΔw. It shares some nodes with the annular diffusion boundary, such as points A and B. Line II is another analysis boundary with a direction angle of (k+1)Δw. It shares some nodes with the annular diffusion boundary, such as points C and D. Assume that the grouting pressure at point A is P i,k , the grouting pressure at point B is P i+1,k , the grouting pressure at point C is P i,k+1 , the grouting pressure at point D is P i+1,k+1 Under the initial grouting conditions, the diffusion radius is the grouting hole diameter r0. The slurry is injected from the grouting hole and diffuses in the crack in a circular shape. For example, the grouting pressure P at point A is calculated first. i,k , at the same direction angle kΔw, the diffusion distance increases Δr to point B, and the grouting pressure P at point B is calculated. i+1,k , keep the direction angle unchanged, increase the diffusion distance one by one, calculate the grouting pressure at each intersection of line I and the annular diffusion boundary, then increase the direction angle kΔw of point A by Δw to point C, and calculate the grouting pressure P at point C i,k+1 , at the same direction angle (k+1)Δw, the diffusion distance increases by Δr to point D, and the grouting pressure P at point D is calculated. i+1,k+1, keeping the direction angle unchanged, increasing the diffusion distance one by one, calculating the grouting pressure at each intersection of line II and the annular diffusion boundary, and finally obtaining the grouting pressure at each point on the entire fracture surface, realizing the estimation of the grouting pressure at different diffusion distances, and also realizing the benchmark estimation of each diffusion radius under the same diffusion pressure.

[0076] The present invention uses spatial unitization to characterize time unitization through spatial unitization calculation, and takes into account the change in slurry viscosity, the change in the width of inclined cracks, and the change in gravity at the inclination angle within the unit time in the estimated calculation of grouting pressure, so that the estimation of grouting pressure is more in line with the problems of uneven and inclined surfaces of actual cracks, and the accuracy of grouting pressure estimation is improved, and the depth calculation of slurry diffusion pressure and diffusion radius under complex working conditions such as inclined cracks and viscous grouting slurry is realized, the rationality of grouting parameter design is improved, the waste of grouting materials in grouting engineering is avoided, the grouting cost is reduced, and effective data can be provided for the design of grouting engineering in the mining field, thereby improving the grouting efficiency and utilization rate.

[0077] Example 2

[0078] The difference between this embodiment and embodiment 1 is that: in embodiment 1, a direction angle is first determined, and the diffusion distance Δr is increased one by one under the direction angle to calculate the grouting pressure of each point on the direction angle, while in this embodiment, a diffusion radius is first determined, and the diffusion direction angle is increased one by one under the diffusion radius to calculate the grouting pressure of each point on the diffusion radius. Figure 2 For example, first calculate the grouting pressure P at point A. i,k , at the same diffusion radius r i,k Under this condition, the diffusion direction angle increases by Δw to point C, and the grouting pressure P at point C is calculated. i,k+1 , keep the diffusion radius unchanged, increase the diffusion direction angle one by one, calculate the grouting pressure at each intersection of line I and the annular diffusion boundary, and then calculate the diffusion radius r of point A. i,k Increase Δr to point B and calculate the grouting pressure P at point B i+1,k , at the same diffusion radius r i+1,k Under this condition, the diffusion angle increases by Δw to point D, and the grouting pressure P at point D is calculated. i+1,k+1 , keeping the diffusion radius unchanged, increasing the diffusion direction angle one by one, calculating the grouting pressure at each intersection of line II and the annular diffusion boundary, and finally obtaining the grouting pressure at each point on the entire fracture surface.

[0079] Steps 1 to 7 of the method of this embodiment are the same as those of Embodiment 1, except that Step 8 and Step 9 are different. Step 8 and Step 9 of this embodiment are as follows:

[0080] Step 8: At the same diffusion radius r i,kThe diffusion direction angle is increased gradually. For example, when the diffusion direction angle reaches (k+1)Δw, the calculation process of steps 1-7 is repeated until k=m, and the diffusion radius r is completed. i,k Estimation of grouting pressure.

[0081] Step 9: Increase the diffusion radius, for example, the diffusion radius is r i+1,k , at the same diffusion radius r i+1,k The diffusion direction angle is increased gradually. For example, when the diffusion direction angle reaches (k+1)Δw, the calculation process of steps 1-7 is repeated until k=m, and the diffusion radius r is completed. i+1,k The grouting pressure is estimated until the estimation of the grouting pressure of the entire fracture surface is completed.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for estimating the multi-directional spatial distribution of viscous slurry pressure in inclined fractures, characterized by: The following steps are involved: S1, the diffusion radius L of the slurry required to be introduced into the crack, the average gap width b, the tilt angle β of the inclined crack, the initial viscosity μ0, the viscosity coefficient η, the grouting hole diameter r0, the external pressure P0, the grouting flow rate q, and the number of diffusion length calculation segments n and the number of direction angle segments m are given; S2, calculate the unit radius Δr and the unit angle Δw; S3. Define the initial pressure as the external pressure P0, the initial diffusion radius as the grouting hole diameter r0, and calculate the slurry diffusion radius r under the same direction angle kΔw. i+1,k and the average diffusion radius S4. Based on the mass balance law, the average diffusion velocity of different diffusion radii under the same direction angle kΔw and unit radius Δr is calculated according to the crack width. Calculate the time Δt required for the diffusion radius to reach the unit radius Δr i,k , the total time after diffusion over a certain distance T(i,k); S5. Calculate the average slurry viscosity that changes with grouting time at the same direction angle kΔw S6. According to the pressure gradient control equation, the grouting pressure gradient ΔP of the unit radius Δr is obtained when the direction angle is kΔw. i,k ; S7, calculate the direction angle kΔw and the diffusion radius r i,k The grouting pressure P in the crack i,k ; S8, increasing diffusion radius r at the same direction angle kΔw i,k , repeat S1-S7 until i=n, ​​and complete the estimation of grouting pressure at the direction angle kΔw; S9, increasing direction angle, increasing diffusion radius r at the same direction angle (k+1)Δw i,k , repeat S1-S7 until i=n, ​​complete the estimation of the grouting pressure at the direction angle of (k+1)Δw, until the estimation of the grouting pressure of the entire fracture surface is completed.

2. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 1 is characterized by: In step S2, the unit radius Δr and the unit angle Δw are calculated by the following formula: Δr=L / n,Δw=2π / m, where L is the slurry diffusion radius, n is the number of diffusion length calculation segments, and m is the number of directional angle segments.

3. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 2 is characterized by: The slurry diffusion radius r in step S3 i+1,k and the average diffusion radius Calculated by the following formula: r i+1,k =r i,k +Δr; Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, r i,k is the slurry diffusion radius at the direction angle kΔw, where the slurry diffusion distance reaches iΔr, and Δr is the unit radius.

4. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 3 is characterized by: The average diffusion rate in step S4 The time Δt required for the diffusion radius to reach the unit radius Δr i,k , the total time T(i,k) after diffusion over a certain distance is calculated by the following formula: in, is the crack width, b is the average crack width, JRC is the rated constant commonly used in rock engineering to characterize crack roughness, j = 0-n.

5. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 4, characterized in that: The average slurry viscosity in step S5 Calculated by the following formula: Among them, μ i,k is the viscosity of the slurry with a diffusion radius of iΔr and a direction angle of kΔw, μ i-1,k is the viscosity of the slurry with a diffusion radius of (i-1)Δr and a direction angle of kΔw, μ i,k =μ0+ηT(i,k),μ i-1,k =μ0+ηT(i-1,k), after rearrangement we can get:

6. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 5, characterized in that: The grouting pressure gradient ΔP in step S6 i,k Calculated by the following formula: Among them, r i+1,k is the slurry diffusion radius when the slurry diffusion distance reaches (i+1)Δr under the direction angle kΔw, is the average slurry viscosity, q is the grouting flow rate, is the crack width, ρ is the slurry density, g is the free acceleration, Δw is the unit angle, k=0-m, m is the number of directional angle segments, β is the tilt angle of the inclined crack, and Δr is the unit radius.

7. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 6, characterized in that: In step S7, the grouting pressure P in the crack i,k Calculated by the following formula: Among them, P i-1,k The direction angle is kΔw and the diffusion radius is r i-1,k The grouting pressure in the crack at that time.

8. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 1, characterized in that: The slurry will show a circular diffusion pattern in each unit direction within the spatial crack. The slurry increases in the diffusion direction by Δw and is represented by the variable k, k=0-m. The slurry increases in the diffusion distance by Δr and is represented by the variable i, i=0-n.

9. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 1, characterized in that: The average gap width b is obtained in field engineering by conventionally measuring rock mass permeability and calculating using the conventional Darcy formula.

10. The method for estimating the multi-directional spatial distribution of the viscous slurry pressure in inclined fractures according to claim 1, characterized in that: The viscosity coefficient η is obtained by measuring the viscosity of the grouting slurry at different times by a viscometer, obtaining the change of the grouting slurry over time, and thus determining the viscosity coefficient η of the grouting slurry.

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