Method for determining rheological parameters of compacted soil-rock mixture in high fill reservoir basin site

Abstract

The application discloses a method for determining the rheological parameters of high fill reservoir site compacted soil and rock mixture, and relates to the technical field, in particular to a method for determining the rheological parameters of site compacted soil and rock mixture, which comprises the following steps: S1, carrying out a flat plate load test and a direct shear test on the surface of the soil and rock mixture reservoir after the site rolling is finished, and obtaining loading-settlement and shear stress-shear displacement data; S2, inversely determining the static force constitutive model parameters of the site compacted soil and rock mixture, and calculating the instantaneous displacement generated by the reservoir filling; S3, combining the displacement monitoring data during the construction period, separating out the displacement generated by rheology, and then inversely determining the rheological parameters. The method avoids the problem that the rheological parameters inversely determined by using the displacement monitoring data during the operation period are difficult to be applied to the reservoir deformation control scheme optimization design in the filling construction stage, and the rheological parameters obtained by the construction period monitoring data have more engineering guiding significance.

Description

Technical Field

[0001] This invention relates to the technical field of determining the rheological parameters of soil-rock mixtures, specifically a method for determining the rheological parameters of on-site compacted soil-rock mixtures in high-fill reservoir basins. Background Technology

[0002] In recent years, my country's pumped storage power station construction has entered a stage of rapid development. To raise the upper reservoir head and achieve earthwork balance within the power station, many power stations use the excavated soil-rock mixture from the lower reservoir as fill material for the upper reservoir basin. To control the settlement and deformation of the high fill of the soil-rock mixture, thin-layer heavy rolling combined with vibration compaction is usually adopted in engineering. Nevertheless, due to the significant rheological properties of the soil-rock mixture, its long-term deformation can still adversely affect the safe operation of the reservoir basin seepage prevention system during the operational period. Therefore, accurately predicting the long-term deformation of the reservoir basin during the construction phase is crucial for setting deformation control measures in advance, determining the pre-settlement time after completion, and ensuring the safe operation of the reservoir basin seepage prevention system.

[0003] Currently, determining the rheological parameters of fill material mainly involves two methods: indoor rheological testing and inversion analysis. For indoor testing, due to the scaling effect in sample size and testing time, it cannot reflect the actual rheological characteristics of the fill material in the field, and the obtained parameters are difficult to accurately predict the long-term deformation of the reservoir. For inversion analysis, displacement monitoring data during operation is typically used for rheological parameter inversion; however, the inversion results can only evaluate the operational safety of the reservoir after completion and cannot guide the implementation of deformation control schemes during the filling construction phase. Furthermore, dam displacement monitored during construction usually includes both instantaneous displacement caused by filling and displacement caused by rheology; it is difficult to accurately separate these two during inversion, making the obtained rheological parameters non-unique and difficult to reasonably predict the long-term deformation of the reservoir. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for determining the rheological parameters of compacted soil-rock mixtures in high-fill reservoir basins, thus solving the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for determining the rheological parameters of on-site compacted soil-rock mixture in high-fill reservoir basins, comprising the following steps:

[0006] S1. When the reservoir basin is filled to a certain height, plate load tests are carried out on the surface of the reservoir basin in different material zones to obtain data of the loading-settlement (ps) curve.

[0007] S2. At the plate load test location, a large-scale direct shear test is carried out simultaneously to obtain data on the shear stress-shear displacement curve and to determine the internal friction angle and cohesion of the compacted soil-rock mixture.

[0008] S3. The Duncan EB model was selected as the static model for compacted soil-rock mixture. Finite element models for plate load test and direct shear test were established. Based on the results of plate load test and direct shear test, the parameters of the EB model for compacted soil-rock mixture were inverted using an improved accelerated genetic algorithm.

[0009] S4. Based on the actual filling construction classification and material zoning of the reservoir basin, establish a three-dimensional finite element model of the reservoir basin;

[0010] S5. The five-parameter model of the Southern Institute of Science and Technology was selected as the rheological model. Using the reservoir basin displacement monitoring data during the construction period, the improved accelerated genetic algorithm was used to invert the rheological parameters. The objective function was to minimize the root mean square error between the calculated settlement and the measured settlement. A set of optimal calculation parameters was obtained, which is the inversion result.

[0011] Optionally, in steps S1 and S2, the corresponding reservoir filling height is not less than 20m when conducting the plate load test and direct shear test.

[0012] Optionally, in step S3, the EB model parameters are inverted using both the plate load test and the direct shear test results. During the inversion analysis, the two sets of finite element meshes for the plate load test and the direct shear test are calculated alternately. The objective function is:

[0013]

[0014] Where j is the number of the loading stage in the plate load test, and n is the total number of loading stages in the plate load test. The measured settlement is given by the j-th load level. Here are the corresponding calculated values; k is the shear force number in the direct shear test, and m is the number of shear forces in the direct shear test. This represents the measured shear displacement corresponding to the shear force k. This is the corresponding calculated value.

[0015] Optionally, the starting time for measuring the displacement of the reservoir basin during the construction period in step S5 shall be at least 6 months, and the instantaneous deformation caused by the filling of the reservoir basin shall be calculated by the static constitutive model parameters determined in step S3.

[0016] This invention provides a method for determining the rheological parameters of on-site compacted soil-rock mixture in high-fill reservoir basins, which has the following beneficial effects:

[0017] For in-situ compacted soil-rock mixtures, this invention proposes a method for inverting the rheological parameters of in-situ compacted soil-rock mixtures based on in-situ load tests, direct shear tests, and displacement monitoring data during the filling construction period. First, vertical load-settlement curves and shear stress-horizontal displacement curves are obtained through plate load tests and direct shear tests. Finite element models of plate load tests and direct shear tests are established. An improved accelerated genetic algorithm is used to invert the static model parameters of the in-situ compacted soil-rock fill material. Then, combined with displacement monitoring data during the construction period, a three-dimensional finite element model of the reservoir basin considering the actual filling process is established. The improved accelerated genetic algorithm is used to invert the rheological parameters of the compacted soil-rock mixture. This method can accurately separate the instantaneous deformation and the rheological deformation over time generated during the construction period, thereby ensuring the accuracy, reliability, and rationality of the inversion results.

[0018] This invention effectively overcomes the problem that the rheological parameters derived from displacement monitoring data during operation cannot guide the implementation of deformation control schemes during construction. At the same time, it overcomes the problem that it is difficult to accurately separate the displacement caused by filling load and rheological displacement during construction. This not only ensures the accuracy and rationality of the inversion results, but also makes the inversion results more meaningful for engineering guidance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the load test of the present invention;

[0020] Figure 2 This is a schematic diagram of the ps curve of the present invention;

[0021] Figure 3 This is a schematic diagram of the direct shear test of the present invention;

[0022] Figure 4 This is a schematic diagram of the shear stress-shear displacement curve of the present invention;

[0023] Figure 5 This is a schematic diagram of the parameter inversion analysis of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Implementation Case 1

[0026] Please see Figures 1 to 5 This invention provides a technical solution: a method for determining the rheological parameters of on-site compacted soil-rock mixture in high-fill reservoir basins, comprising the following steps:

[0027] S1. When the reservoir basin is filled to a certain height, plate load tests are carried out on the surface of the reservoir basin in different material zones to obtain data of the loading-settlement (ps) curve.

[0028] S2. At the plate load test location, a large-scale direct shear test is carried out simultaneously to obtain data on the shear stress-shear displacement curve and to determine the internal friction angle and cohesion of the compacted soil-rock mixture.

[0029] In steps S1 and S2, the corresponding reservoir filling height is not less than 20m when conducting plate load test and direct shear test.

[0030] S3. The Duncan EB model was selected as the static model for compacted soil-rock mixture. Finite element models for plate load test and direct shear test were established. Based on the results of plate load test and direct shear test, the parameters of the EB model for compacted soil-rock mixture were inverted using an improved accelerated genetic algorithm.

[0031] The parameters of the EB model were retrieved using the results of plate load and direct shear tests. During the inversion analysis, two sets of finite element meshes from the plate load and direct shear tests were calculated alternately. The objective function was:

[0032]

[0033] Where j is the number of the loading stage in the plate load test, and n is the total number of loading stages in the plate load test. The measured settlement is given by the j-th load level. Here are the corresponding calculated values; k is the shear force number in the direct shear test, and m is the number of shear forces in the direct shear test. This represents the measured shear displacement corresponding to the shear force k. The corresponding calculated value;

[0034] S4. Based on the actual construction classification and material zoning of the reservoir basin, establish a three-dimensional finite element model of the reservoir basin;

[0035] S5. The five-parameter model of the Southern Institute of Science and Technology was selected as the rheological model. The reservoir basin displacement monitoring data during the construction period was used to invert the rheological parameters using an improved accelerated genetic algorithm. The objective function was to minimize the root mean square error between the calculated settlement and the measured settlement. A set of optimal calculation parameters was obtained, which is the inversion result.

[0036] The starting time for measuring the displacement of the reservoir basin during the construction period is at least 6 months. The instantaneous deformation caused by the filling of the reservoir basin is calculated by the static constitutive model parameters determined in step S3.

[0037] Implementation Case 2

[0038] like Figure 1-5 As shown, a method for determining the rheological parameters of on-site compacted soil-rock mixture includes the following steps:

[0039] Step 1: Pre-install four large shear frames of 1.2 x 1.2 m. Then, follow the normal reservoir filling process to lay and compact the material. In this case, a 26-ton high-power vibratory roller is used to compact the soil-rock mixture. The compaction layer thickness is 60 cm, the vehicle speed is 2-3 km / h, the number of compaction passes is 8, and the excitation force is 410 kN.

[0040] Step 2: Conduct a plate load test on the surface of the compacted soil-rock mixture basin to obtain the settlement displacement of the compacted soil-rock mixture under different loads;

[0041] Step 3: Conduct large-scale direct shear tests on the surface of the compacted soil-rock mixture basin to obtain the shear stress-shear displacement curves of the compacted soil-rock mixture under different vertical loads, and use the Mohr-Coulomb strength criterion to determine the internal friction angle and cohesion of the compacted soil-rock mixture in the field.

[0042] Step 4: Using the Duncan EB model as the static constitutive model for the material, and based on the ps curve obtained from the plate load test and the shear stress-shear displacement curve obtained from the direct shear test, an objective function is established. An improved accelerated genetic algorithm is then used to optimize the EB model parameters K and K0 for the in-situ compacted soil-rock mixture. b Inverse operations are performed on n and m;

[0043]

[0044] Where j is the number of the loading stage in the plate load test, and n is the total number of loading stages in the plate load test. The measured settlement is given by the j-th load level. Here are the corresponding calculated values; k is the shear force number in the direct shear test, and m is the number of shear forces in the direct shear test. This represents the measured shear displacement corresponding to the shear force k. This is the corresponding calculated value.

[0045] Step 5: Based on the actual filling grading and material zoning of the reservoir basin, establish a three-dimensional finite element model of the reservoir basin, use the determined EB model parameters to calculate the instantaneous displacement generated by filling, and combine the displacement monitoring data during the construction period to separate the displacement generated by rheology at each measuring point during the construction period.

[0046] Step 6: Select the five-parameter rheological model of the Southern Institute of Science and Technology, establish the objective function, and use the improved accelerated genetic algorithm to obtain the rheological parameters of the compacted soil-rock mixture in the field.

[0047] In summary, the basic idea of ​​this invention is to first use the ps curves and shear stress-shear displacement curves obtained from plate load tests and field direct shear tests as monitoring data for the inversion of Duncan EB model parameters, and then use the displacement monitoring data during the construction period to separate the displacement generated by rheology, and then invert the rheological parameters of the field compacted soil-rock mixture.

[0048] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for determining the rheological parameters of on-site compacted soil-rock mixture in a high-fill reservoir basin, characterized in that, Includes the following steps: S1. When the reservoir basin is filled to a certain height, plate load tests are carried out on the surface of the reservoir basin in different material zones to obtain data on the loading-settlement curves. S2. At the plate load test location, a large-scale direct shear test is carried out simultaneously to obtain data on the shear stress-shear displacement curve and to determine the internal friction angle and cohesion of the compacted soil-rock mixture. S3. The Duncan EB model was selected as the static model for compacted soil-rock mixture. Finite element models for plate load test and direct shear test were established. Based on the results of plate load test and direct shear test, the parameters of the EB model for compacted soil-rock mixture were inverted using an improved accelerated genetic algorithm. S4. Based on the actual filling construction classification and material zoning of the reservoir basin, establish a three-dimensional finite element model of the reservoir basin; S5. The five-parameter model of the Southern Institute of Science and Technology was selected as the rheological model. The displacement monitoring data of the reservoir basin during the construction period was used to invert the rheological parameters using an improved accelerated genetic algorithm. The objective function was to minimize the root mean square error between the calculated settlement and the measured settlement. A set of optimal calculation parameters was obtained, which is the inversion result. In step S3, the EB model parameters are inverted using the results of the plate load test and direct shear test. During the inversion analysis, the two sets of finite element meshes for the plate load test and the direct shear test are calculated alternately. The objective function is: Where j is the number of the loading stage in the plate load test, and n is the total number of loading stages in the plate load test. The measured settlement is under the j-th load level. Here are the corresponding calculated values; k is the shear force number in the direct shear test, and m is the number of shear forces in the direct shear test. This represents the measured shear displacement corresponding to the shear force k. This is the corresponding calculated value.

2. The method for determining the rheological parameters of on-site compacted soil-rock mixture in a high-fill reservoir basin according to claim 1, characterized in that, In steps S1 and S2, the corresponding reservoir filling height is not less than 20m when conducting plate load tests and direct shear tests.

3. The method for determining the rheological parameters of on-site compacted soil-rock mixture in a high-fill reservoir basin according to claim 1, characterized in that, The starting time for measuring the displacement of the reservoir basin during the construction period in step S5 is at least 6 months, and the instantaneous deformation of the reservoir basin caused by filling is calculated by the static constitutive model parameters determined in step S3.

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