A curtain grouting unit time slurry injection amount prediction method

Abstract

The application discloses a curtain grouting unit time slurry injection amount prediction method and belongs to the technical field of seepage prevention treatment of water conservancy and hydropower projects. The method comprises the following steps: firstly, determining slurry fluidity correction coefficients under different water-cement ratios and diffusion correction coefficients under different pressures through experiments; calculating a unit time slurry injection amount prediction initial value based on the Lugeon value, the and the slurry pressure correction coefficient of a water pressure test; and obtaining a prediction final value in combination with a rock stratum permeability rate influence coefficient. The application comprehensively considers slurry performance, grouting pressure and rock mass permeability characteristics, improves prediction accuracy through multi-factor coupling and dynamic correction, solves the problem that a traditional method depends on experience and has a large deviation, can provide a scientific basis for grouting material preparation, progress control and cost management, and is suitable for curtain grouting construction of projects such as dams.

Description

Technical Field

[0001] This invention belongs to the field of basic seepage prevention technology in water conservancy and hydropower engineering, specifically involving a method for predicting the amount of grout injected per unit time in curtain grouting, which is applicable to the prediction of grouting volume during the curtain grouting construction process in projects such as dams. Background Technology

[0002] Curtain grouting is one of the key technologies for rock mass seepage prevention. Accurate prediction of the amount of grout injected per unit time during its construction is of great significance for grouting material preparation, construction progress control and project cost management.

[0003] Traditional prediction methods largely rely on the Lurong value (LU) obtained from water pressure tests and estimate the grouting volume based on empirical formulas. They fail to systematically consider the impact of grout fluidity, diffusivity, and differences in rock strata permeability on the grouting volume, resulting in low prediction accuracy and large deviations from the actual grouting volume. Furthermore, existing methods lack dynamic correction mechanisms for construction parameters such as grout water-cement ratio and grouting pressure, making them unsuitable for grouting operations under complex geological conditions.

[0004] Therefore, there is an urgent need for a method to predict the amount of grout injected per unit time that can comprehensively consider the grout properties, grouting pressure, and rock mass permeability characteristics, so as to improve the scientific and economic efficiency of grouting construction. Summary of the Invention

[0005] The purpose of this invention is to provide a method for predicting the amount of grout injected per unit time in curtain grouting, which solves the problems of traditional methods that rely solely on experience to estimate the amount of grout injected per unit time, resulting in low prediction accuracy and large deviations from actual construction. This provides an accurate basis for material configuration, progress control, and cost management in grouting construction, thereby improving the scientific, economic, and safe aspects of curtain grouting construction.

[0006] To achieve the above objectives, the technical solution of this invention is as follows: A method for predicting the amount of grout injected per unit time in curtain grouting, the method comprising: The correction coefficient for cement slurry fluidity under different water-cement ratios was determined using the Marviate funnel test. ; The correction coefficient for cement slurry diffusivity under different pressures was determined by indoor pressure diffusion tests. ; The Lvrong value LU of the section to be irrigated is obtained by conducting a water pressure test on the section to be irrigated. Based on the aforementioned cement slurry fluidity correction coefficient Cement slurry diffusivity correction factor And the initial value of the predicted slurry injection volume per unit time calculated by Lv Rongzhi LU. ; The influence coefficient of rock permeability was determined through on-site grouting tests. ; Predict the initial value based on the slurry injection volume. and the influence coefficient of rock stratum permeability Calculate the predicted final value of grout injection volume per unit time .

[0007] Furthermore, the correction coefficient for the fluidity of cement slurry under different water-cement ratios... The calculation method is as shown in equation (1): In the formula: This is a correction factor for slurry fluidity; Water-cement ratio; The flow time of cement slurry with different water-cement ratios; This refers to the time it takes for the water to flow.

[0008] Furthermore, the correction coefficient for the diffusivity of cement slurry under different pressures... The calculation method is as shown in equation (2): In the formula: This is the correction factor for slurry diffusivity; The grouting pressure; This represents the diffusion distance of the slurry under different pressures. This represents the water diffusion distance under different pressures.

[0009] Furthermore, the initial value of the predicted slurry injection volume per unit time. The calculation method is as shown in equation (3): =LU ( ) ( ) / 1000 (3) In the formula: LU is the Lü Rong value obtained from the water pressure test; n The total number of grout water-cement ratio types to be used in the grouting section; This refers to the water-cement ratio type of the slurry; This is a correction factor for slurry fluidity; m This represents the total number of grouting pressure types to be used in the grouting section. This refers to the grouting pressure type serial number; This is the correction factor for slurry diffusivity; The correction factor for grout pressure is 1000 in formula (3), which is a dimensional conversion factor used to convert the Lv Rong value to m. 3 / min unit.

[0010] Furthermore, the predicted final value of the slurry injection volume per unit time The calculation method is as shown in equation (4): (4) In the formula, The final predicted value of grout injection volume per unit time; LU is the Lü Rong value obtained from the water pressure test; This is the coefficient affecting the permeability of the rock strata.

[0011] Furthermore, the influence coefficient of the rock stratum permeability K k The calculation method is as shown in equation (5): (5) In the formula, LU is the Lü Rong value obtained from the water pressure test, and the unit is 1. Lu ; For the on-site grouting test, LU<10 Lu The total number of grouting hole sections; 10 for on-site grouting test Lu ≤LU<100 Lu The total number of grouting hole sections; For the on-site grouting test, LU≥100 Lu The total number of grouting hole sections; The initial value for the predicted grout injection volume per unit time for the i-th grouting hole segment. Calculated according to formula (3); This represents the measured grout injection volume per unit time for the i-th grouting hole segment in the grouting test.

[0012] The present invention also discloses an apparatus comprising: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the curtain grouting unit time grout injection volume prediction method.

[0013] The present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for predicting the amount of grout injected per unit time in curtain grouting.

[0014] The technical solution of this invention has the following technical effects: 1. This invention systematically couples grout fluidity, grout diffusion, grouting pressure, and rock mass permeability to construct a multi-parameter corrected prediction model, overcoming the limitations of traditional methods that rely solely on empirical estimation of Lü Rong values. The prediction principle is more consistent with the seepage and diffusion laws of curtain grouting.

[0015] 2. This invention introduces the influence coefficient of rock permeability calibrated by on-site grouting test to dynamically correct the initial predicted value, which can adapt to changes in different geological conditions, significantly reduce the deviation between the predicted value and the actual injection volume, and improve the reliability of the prediction results.

[0016] 3. This invention can accurately predict the amount of grout injected per unit time before construction, providing a quantitative basis for grout preparation, material reserves, construction schedule arrangement and project cost control, avoiding material waste or insufficient supply, and improving construction efficiency and economy.

[0017] 4. The method of the present invention is simple to operate, the parameters are easy to obtain, and the calculation logic is clear. It is applicable to rock curtain grouting construction of various water conservancy and hydropower projects such as dams, reservoirs, and dikes, and has good engineering applicability and promotion prospects. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method for predicting the amount of grout injected per unit time in curtain grouting according to the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific examples described herein are only some embodiments of this invention, not all embodiments, and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0020] like Figure 1 As shown, the method for predicting the amount of grout injected per unit time in curtain grouting according to the present invention includes the following steps: 1) Establish correction coefficients for slurry fluidity based on different water-cement ratios. Based on the Marsh funnel test, the outflow time of cement slurry under different water-cement ratios of 5, 3, 2, 1, 0.7, and 0.5 was tested, and a calculation model for the fluidity correction coefficient of cement slurry with different water-cement ratios was constructed, as shown in equation (1): In the formula: The fluidity correction coefficient is dimensionless and represents the ratio of the fluidity of slurry to that of water. The larger the value, the better the fluidity and the closer it is to the fluidity of water. The flow time of cement slurry obtained from Marvibling funnel tests with different water-cement ratios is expressed in seconds. The flow time obtained from the Marviate funnel test in water is a standard value commonly used in the industry, taken as 26s, which is applicable to normal temperature and standard Marviate funnel test conditions. The water-cement ratio is dimensionless. Correction coefficients for other water-cement ratios can be calculated using the model described above, based on actual engineering requirements.

[0021] It depends on the water-cement ratio The flow time of cement slurry with different water-cement ratios obtained from the Marviate funnel test Flow time obtained from the Marvate funnel test in water A function determined by three parameters The piecewise function logic is as follows: For six different water-cement ratios, a Marviator funnel test is conducted, and the correction factor is calculated using a unified formula: = If the slurry to be tested =5, then = If the slurry to be tested =0.5, then = .

[0022] 2) Establish correction coefficients for grout diffusivity based on different grouting pressures. Through indoor experiments, the ratio of the diffusion distance of cement grout under different grouting pressures (0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, and 5 MPa) to the diffusion distance of water under the same pressure was tested. A calculation model for the correction coefficient of cement grout diffusivity under different pressures was constructed, as shown in equation (2): In the formula: The dimensionless correction coefficient for grout diffusivity represents the ratio of the diffusivity of cement grout to that of water under the same grouting pressure. The larger the value, the better the diffusivity. The diffusion distance of the slurry under different pressures, in cm; The distance of water diffusion under different pressures, in cm; The pressure is grouting pressure, in MPa. Correction coefficients for grout diffusivity under other pressures can be calculated using the above model based on actual engineering requirements.

[0023] It is determined by grouting pressure Diffusion distance of slurry under different pressures Water diffusion distance under different pressures A function determined by three parameters The piecewise function logic is as follows: For six different grouting pressure values, the ratio of the cement grout diffusion distance under different grouting pressures to the water diffusion distance under the same pressure is tested, and the correction coefficient is calculated using a unified formula. = ;like 0.5MPa, then = ;like 5MPa, then = .

[0024] 3) Establish an initial model for predicting slurry injection volume per unit time. The water pressure test is a preliminary step before grouting. The Lurong value (LU) obtained from the water pressure test represents the amount of water that can be injected into the rock mass, and it provides a possibility for predicting the subsequent grouting volume. Based on the Lurong value obtained from the water pressure test and the grout fluidity correction coefficient obtained from the above model, and slurry diffusivity correction factor This allows for a preliminary prediction of the grout injection volume per unit time, as shown in equation (3): =LU ( ) ( ) / 1000 (3) In the formula: LU is the Lürgöl value obtained from the water pressure test, in units of... Lu ; n The total number of grout water-cement ratio types to be used in the grouting section; This refers to the water-cement ratio type of the slurry; This is a correction factor for slurry fluidity; m This represents the total number of grouting pressure types to be used in the grouting section. This is the grout pressure correction coefficient, which represents the ratio of grouting pressure to water pressure test pressure. The water pressure test pressure is typically 1.0 MPa, while the commonly used pressure for curtain grouting in engineering projects is 1.25 MPa. There is a fixed pressure ratio between the two. This coefficient is derived from grouting specifications for water conservancy and hydropower projects and statistical analysis of a large amount of engineering measurement data. It reflects the influence of pressure increase on grout diffusion and injection volume, and is generally taken as 1.25. When the maximum grouting pressure exceeds 1.25 MPa... =Design maximum grouting pressure / 1, which is dynamically determined based on the ratio of the actual grouting pressure to the standard water pressure of 1.0MPa, and is dimensionless; This is the grouting pressure type number. This is the initial value for the predicted slurry injection volume per unit time, in meters. 3 / min; In formula (3), 1000 is a dimension conversion coefficient used to convert Lü Rong's value to m 3 / min unit.

[0025] In another embodiment of the present invention, when a set of grouting parameters actually used in a single grouting hole section includes a uniquely determined grout water-cement ratio and a uniquely determined grouting pressure, =LU / 1000.

[0026] 4) Establish the final model for predicting slurry injection volume per unit time. To further improve the model's prediction accuracy, the influence of permeability grading is added to the initial prediction model, which is characterized as the effect of rock layers with different permeability on the amount of grout injected per unit time, as shown in equation (4): (4) In the formula, The final predicted value of grout injection volume per unit time, in meters. 3 / min. The permeability coefficient of the rock stratum is dimensionless and can be calculated based on the field grouting test, as shown in equation (5): (5) In the formula, LU is the Lü Rong value obtained from the water pressure test, and the unit is 1. Lu ; For the on-site grouting test, LU<10 Lu The total number of grouting hole sections; For on-site grouting tests, 10Lu≤LU<100 Lu The total number of grouting hole sections; For the on-site grouting test, LU≥100 Lu The total number of grouting hole sections; Predict the initial value of the grout injection volume per unit time for the i-th grouting hole segment; The measured grout injection volume per unit time for the i-th grouting hole section in the grouting test, in m³. 3 / min.

[0027] The specific implementation of the present invention will be further described below with reference to specific embodiments: Step 1: Obtaining slurry flowability parameters Based on the proposed water-cement ratios (e.g., 0.5, 0.7, 1, 2, 3, 5) in the engineering design, a Marviate funnel test was conducted according to specifications to determine the outflow time of the slurry for each water-cement ratio. Using a water outflow time of 26 seconds as a baseline, the slurry fluidity correction coefficients for different water-cement ratios were calculated using a constructed model. .

[0028] Step 2: Obtaining slurry diffusivity parameters In the laboratory, simulating on-site grouting pressure conditions (e.g., 0.5, 1, 2, 3, 4, 5 MPa), radial diffusion tests were conducted on cement grout and water, measuring their diffusion distances under the same pressure and time. Based on the calculation model for the cement grout diffusivity correction coefficient under different pressures, the grout diffusivity correction coefficients for each pressure level were calculated. .

[0029] Step 3: Prediction of Initial Grouting Volume Before grouting, the Lü Rong value (LU) of the section to be grouted is obtained through a water pressure test. Based on the number of water-cement ratio types (n) and grouting pressure levels (m) determined in the construction plan, the corresponding water-cement ratio-related grout fluidity correction coefficient and grouting pressure-related grout diffusivity correction coefficient are selected from the parameter database established in steps 1 and 2. The grout pressure correction coefficient is determined based on the maximum grouting pressure. By substituting the values ​​into the initial model for predicting grout injection volume per unit time, the initial predicted value of the grout injection volume per unit time for that borehole section can be calculated. .

[0030] Step 4: Calibration of the permeability influence coefficient Representative geological sections were selected, and a certain number of grouting holes were chosen for on-site grouting tests. The measured Lü Rong value (LU) for each test hole section was recorded (unit: Lü Rong value). Lu ), and categorize them according to their size (LU<10) Lu 10 Lu ≤LU<100 Lu LU≥100 Lu During the grouting process, the actual grouting volume per unit time for each borehole section is accurately measured. The permeability influence coefficient applicable to the geological conditions of this project site is calculated according to formula (5). .

[0031] Step 5: Prediction and Application of Final Grouting Volume The initial predicted value obtained in step 3 The permeability influence coefficient obtained in step 4 Multiplying these values ​​yields a more accurate final prediction of the grout injection volume per unit time, corrected for geological conditions. .

[0032] Step 6: Dynamically guide construction Will This serves as a reference target value for construction control of this grouting section. During actual grouting, the value can be adjusted based on the real-time grouting rate and... By comparing the results, the grouting pressure or grout ratio can be dynamically adjusted to achieve optimized control of the grouting process.

[0033] Through the above steps, the implementation of the method for predicting the amount of grout injected per unit time in curtain grouting according to the present invention is completed.

[0034] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of predicting the slurry injection amount per unit time in a curtain grouting, characterized by, The method includes: Determination of cement paste fluidity correction coefficient under different water-cement ratio ; Determination of cement slurry fluid loss correction factor at different pressures ; Determine the Lv Rong value (LU); According to the cement slurry fluidity correction coefficient , cement slurry diffusion correction coefficient And the initial value of the cement slurry injection amount per unit time is calculated by the Lü Rong value LU ; Determining a permeability impact factor for a rock formation ; The initial value of the slurry injection rate prediction is determined according to the slurry injection rate and the permeability influence coefficient of the rock stratum The final value of the slurry injection rate prediction per unit time is calculated ; The correction coefficient for cement slurry fluidity under different water-cement ratios The calculation method is as shown in equation (1): ； In the formula: This is a correction factor for slurry fluidity; Water-cement ratio; The flow time of cement slurry with different water-cement ratios; The time of water flow; The cement slurry diffusivity correction coefficient under different pressures The calculation method is as shown in equation (2): ； In the formula: This is the correction factor for slurry diffusivity; The grouting pressure; This represents the diffusion distance of the slurry under different pressures. This represents the water diffusion distance under different pressures; The influence coefficient of rock stratum permeability The calculation method is as shown in equation (5): （5） In the formula, LU is the Lü Rong value obtained from the water pressure test, and the unit is 1. Lu ; For the on-site grouting test, LU<10 Lu The total number of grouting hole sections; 10 for on-site grouting test Lu ≤LU<100 Lu The total number of grouting hole sections; For the on-site grouting test, LU≥100 Lu The total number of grouting hole sections; Predict the initial value of the grout injection volume per unit time for the i-th grouting hole segment; This represents the measured grout injection volume per unit time for the i-th grouting hole segment in the grouting test.

2. The method for predicting the amount of grout injected per unit time in curtain grouting according to claim 1, characterized in that, The predicted initial value of the slurry injection volume per unit time The calculation method is as shown in equation (3): =LU ( ) ( ) / 1000 (3) In the formula: LU is the Lü Rong value obtained from the water pressure test; n The total number of grout water-cement ratio types to be used in the grouting section; This refers to the water-cement ratio type of the slurry; This is a correction factor for slurry fluidity; m This represents the total number of grouting pressure types to be used in the grouting section. This refers to the grouting pressure type serial number; This is the correction factor for slurry diffusivity; This is the correction factor for slurry pressure.

3. The method for predicting the amount of grout injected per unit time in curtain grouting according to claim 1, characterized in that, The predicted final value of the slurry injection volume per unit time The calculation method is as shown in equation (4): （4） In the formula, The final predicted value of grout injection volume per unit time; LU is the Lü Rong value obtained from the water pressure test; The coefficient representing the influence of rock stratum permeability; The initial value for the predicted slurry injection volume per unit time.

4. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 3.

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