CN-122021211-A - Discrete element soil multidimensional coupling bearing capacity boundary determination method

CN122021211ACN 122021211 ACN122021211 ACN 122021211ACN-122021211-A

Abstract

The application discloses a discrete element soil multidimensional coupling bearing capacity boundary determination method which comprises the steps of establishing a granular soil model, setting a loading plate, conducting sensitivity test on soil particles, calibrating material parameters of the granular soil model according to test results, conducting repeated penetration experiments according to the granular soil model, verifying the granular soil model, loading the granular soil model through the loading plate according to verification of the granular soil model, obtaining failure parameters, and fitting the failure parameters to obtain an analytical expression of the bearing capacity boundary of soil. The method for determining the multidimensional coupling bearing capacity boundary of the discrete element soil can determine the multidimensional coupling bearing capacity boundary of the soil under the condition of considering the three-dimensional failure behavior of the soil under the combined action of the vertical force, the horizontal force and the bending moment, thereby accurately predicting the bearing capacity of the soil under the complex load.

Inventors

XU NAN
JIN CHANGCHENG
Song Runhan
LEI YUANYI
ZHU RUXIN
LI JINCHENG

Assignees

吉林大学

Dates

Publication Date: 20260512
Application Date: 20251216

Claims (10)

1. A method for determining a multi-dimensional coupling bearing capacity boundary of discrete element soil is characterized by comprising the following steps: Establishing a granular soil model, and setting a loading plate, wherein the granular soil model is used for representing the state of soil through soil particles, and the loading plate is used for simulating the action of walking equipment on the soil; carrying out sensitivity test on the soil particles, and calibrating material parameters of the granular soil model according to test results, wherein the sensitivity is used for representing the sensitivity degree of the output of the granular soil model to the material parameters, the material parameters are used for representing the contact performance between the soil particles and the loading plate, and the material parameters are also used for representing the contact performance between the soil particles; Repeating a penetration experiment according to the granular soil model, and verifying the granular soil model; According to the verification of the granular soil model, loading the granular soil model through the loading plate, and obtaining failure parameters, wherein the failure parameters are used for representing the bearing capacity of the granular soil model on the vertical force, the bearing capacity of the horizontal force and the bearing capacity of the bending moment of the loading plate; and fitting the failure parameters to obtain an analytical expression of the bearing capacity boundary of the soil.
2. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 1, wherein the step of establishing a granulated soil model and arranging a loading plate comprises the following steps: Acquiring property parameters of the soil, and determining the poisson ratio, density and shear modulus of the granular soil model according to the property parameters; determining the shape, size and particle size distribution of the soil particles according to the property parameters; and determining the recovery coefficient, the dynamic friction coefficient and the static friction coefficient among the soil particles according to the property parameters.
3. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 2, wherein the steps of establishing a granulated soil model and arranging a loading plate further comprise: Determining the shape of the loading plate and the material of the loading plate according to the acting position of the soil and the walking equipment; and determining the recovery coefficient, the dynamic friction coefficient and the static friction coefficient between the soil particles and the loading plate according to the material of the loading plate and the property parameters.
4. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 3, wherein the steps of establishing a granulated soil model and arranging a loading plate further comprise: Setting a boundary structure body, wherein the soil particles are arranged in the boundary structure body, and the boundary structure body is used for limiting the soil particles; and determining the coefficient of restitution, the coefficient of dynamic friction and the coefficient of static friction between the soil particles and the boundary structure body according to the property parameters.
5. The method for determining the multi-dimensional coupling bearing capacity boundary of discrete element soil according to claim 4, wherein the step of performing a sensitivity test on the soil particles and calibrating the material parameters of the granular soil model according to the test result comprises the following steps: Carrying out a stacking angle experiment on the soil and acquiring stacking angle experiment data; repeating the stacking angle experiment on the soil particles to obtain the sensitivity of the material parameters; And calibrating the material parameter according to the sensitivity of the material parameter until the error between the stacking angle of the soil particles in the stacking angle experiment and the stacking angle experiment data is smaller than a first passing error.
6. The method for determining the multi-dimensional coupling bearing capacity boundary of discrete element soil according to claim 5, wherein the step of repeating the stacking angle experiment on the soil particles to obtain the sensitivity of the material parameter comprises the following steps: providing a cylinder on the boundary structure and filling the cylinder with compacted soil particles; controlling the cylinder to move vertically upwards at a uniform speed, so that the cylinder is separated from the soil particles, and the soil particles naturally fall down on the boundary structure body and are accumulated into soil particle dunes; recording the stacking angle of the soil particle dunes; Changing the material parameters, and repeating the steps to obtain the material parameter variation delta and the pile-up angle variation delta P of the soil particle dunes; the sensitivity coefficient S of the material parameter is calculated according to the following formula: S= ; judging that the material parameter is insensitive according to S < 0.01; judging that the material parameter is low in sensitivity according to S which is more than or equal to 0.01 and less than 0.05; judging the sensitivity in the material parameters according to S which is more than or equal to 0.05 and less than or equal to 0.2; And judging that the material parameter is highly sensitive according to the fact that S is more than or equal to 0.2.
7. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 1, wherein the steps of repeating the penetration experiment according to the granular soil model and verifying the granular soil model comprise the following steps: performing a penetration experiment on the soil through the penetration body, and recording the penetration depth of the penetration body as a first penetration depth; establishing a penetrating body model according to the penetrating body; setting the penetration body model in the granular soil model according to the data of the penetration experiment; Loading the penetrating body model, and recording the penetrating depth of the penetrating body model as a second penetrating depth; Correcting parameters of the granular soil model according to the fact that the error of the first penetration depth and the second penetration depth is larger than or equal to the second pass error, and repeating the steps; and judging that the verification of the granular soil model is passed according to the fact that the error of the first penetration depth and the second penetration depth is smaller than the second pass error.
8. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 1, wherein the step of loading the granular soil model through the loading plate and acquiring failure parameters comprises the following steps: Loading the granular soil model in the vertical direction through the loading plate, and acquiring a limit value of the granular soil model on vertical force bearing; loading the granular soil model in multiple inclined directions through the loading plate, and acquiring first data of each loading, wherein the first data are used for bearing limit values of the granular soil model on vertical force and horizontal force; carrying out multiple bending moment loading on the granular soil model through the loading plate, and obtaining second data of each loading, wherein the second data are used for representing the bearing limit value of the granular soil model on vertical force and bending moment; And carrying out multiple composite loading on the granular soil model through the loading plate, and obtaining third data of each loading, wherein the third data are used for representing the bearing limit value of the granular soil model on horizontal force and bending moment, and the composite loading is that the loading plate carries out displacement loading and composite bending moment loading on the granular soil model.
9. The method for determining the boundary of the multidimensional coupling bearing capacity of the discrete element soil according to claim 8, wherein the step of loading the granular soil model in a plurality of oblique directions through the loading plate and acquiring the first data of each loading comprises the steps of: Determining the angle of the oblique direction to the vertical direction And obtains the displacement of the loading plate in the horizontal direction according to the following formula And displacement in the vertical direction : Displacement of the loading plate in the horizontal direction And displacement in the vertical direction Loading the loading plate and acquiring the first data; executing the steps for a plurality of times; the step of loading the granular soil model with a plurality of bending moments through the loading plate and obtaining second data of each loading comprises the following steps: Taking a plurality of first values in the range of 0 to Vmax, wherein Vmax is the limit value of the granular soil model on vertical force load; The loading bending moment M of the loading plate is determined according to the following formula: Wherein a is a proportionality coefficient, t is simulation time, Time for starting loading; Repeating the following steps until each first value is loaded; Loading the loading plate according to a first numerical value and a bending moment M, and acquiring the second data; the step of carrying out multiple composite loading on the granular soil model through the loading plate and obtaining third data of each loading comprises the following steps: Taking a plurality of second values in the range of 0 to Vmax; Taking a plurality of third numerical values in the range of 0 to Mmax, wherein Mmax is the limit value of the granular soil model on the load of bending moment; Repeating the following steps until each second numerical value and the third numerical value corresponding to each second numerical value are loaded; and loading the loading plate according to the second numerical value and the third numerical value, and recording the horizontal force born by the loading plate when the granular soil model fails so as to acquire the third data.
10. The method for determining the bearing capacity boundary of the discrete element soil multidimensional coupling according to claim 9, wherein the step of fitting the failure parameters to obtain an analytical expression of the bearing capacity boundary of the soil comprises the steps of: drawing a first failure envelope of the vertical force-horizontal force plane according to a plurality of first data; Drawing a second failure envelope of the bending moment to load plate width ratio-vertical force plane according to a plurality of second data; drawing a third failure envelope curve of a horizontal force plane, which is the ratio of bending moment to loading plate width, according to a plurality of third data; fitting the first failure envelope, the second failure envelope and the third failure envelope, normalizing the vertical force, the horizontal force and the bending moment to obtain an analytical expression of the load bearing capacity boundary of the soil, Wherein the vertical force is normalized by the following formula: v=V/Vmax; V is the vertical force after normalization and V is the vertical force before normalization; the horizontal force is normalized by the following formula: h=H/Vmax; h is the horizontal force after normalization treatment, and H is the horizontal force before normalization treatment; Normalizing the bending moment by the following formula: m=M/Vmax; m is the horizontal force after normalization processing, and M is the horizontal force before normalization processing; the analytical expression of the bearing capacity boundary of the soil is as follows: Is the fitting coefficient.

Description

Discrete element soil multidimensional coupling bearing capacity boundary determination method Technical Field The application relates to the technical field of soil mechanics, in particular to a discrete element soil multidimensional coupling bearing capacity boundary determination method. Background In vehicle ground mechanics, robot field movement and offshore engineering, soil is used as a key supporting medium, and accurate assessment of the bearing capacity of the soil directly relates to engineering structure safety and mobile equipment operation stability, so that accurate prediction of the bearing capacity of the soil under complex loads is of great importance. Under practical conditions, the soil often bears the combined load action of vertical force, horizontal force and bending moment at the same time. In the prior art, an empirical formula or a simplified theoretical model is mainly adopted for analyzing the bearing capacity of soil. However, the three-dimensional failure behavior of the soil under the combined action of the vertical force, the horizontal force and the bending moment cannot be considered in the prior art, so that the three-dimensional failure mechanism of the soil under the combined action of the vertical force, the horizontal force and the bending moment cannot be accurately described, and the bearing capacity of the soil under the complex load cannot be accurately predicted in the prior art. Disclosure of Invention The application aims to at least solve the problem that the prior art cannot consider the three-dimensional failure behavior of soil under the combined action of vertical force, horizontal force and bending moment. The aim is achieved by the following technical scheme: The application provides a discrete element soil multidimensional coupling bearing capacity boundary determining method, which comprises the following steps: Establishing a granular soil model, and setting a loading plate, wherein the granular soil model is used for representing the state of soil through soil particles, and the loading plate is used for simulating the action of walking equipment on the soil; carrying out sensitivity test on the soil particles, and calibrating material parameters of the granular soil model according to test results, wherein the sensitivity is used for representing the sensitivity degree of the output of the granular soil model to the material parameters, the material parameters are used for representing the contact performance between the soil particles and the loading plate, and the material parameters are also used for representing the contact performance between the soil particles; Repeating a penetration experiment according to the granular soil model, and verifying the granular soil model; According to the verification of the granular soil model, loading the granular soil model through the loading plate, and obtaining failure parameters, wherein the failure parameters are used for representing the bearing capacity of the granular soil model on the vertical force, the bearing capacity of the horizontal force and the bearing capacity of the bending moment of the loading plate; and fitting the failure parameters to obtain an analytical expression of the bearing capacity boundary of the soil. According to the discrete element soil multidimensional coupling bearing capacity boundary determination method, macroscopic soil properties are simulated through the action of microscopic soil particles, so that soil mechanical behaviors can be more truly captured. By establishing a granulated soil model and arranging a loading plate, a foundation can be provided for researching the three-dimensional failure behavior of soil under the combined action of vertical force, horizontal force and bending moment. By performing sensitivity test on the soil particles, the material parameters of the granular soil model can be targeted and marked according to the test result, so that the fitness of the granular soil model and the soil is improved, and the calibration efficiency of the material parameters can be improved. The penetration experiment is repeated according to the granular soil model, and the granular soil model is verified, so that the error between the macroscopic state of the granular soil model and the macroscopic state of soil can be verified, and the fitness of the granular soil model and the soil can be verified. The method can comprehensively capture the bearing capacity boundary of the soil under complex load and determine the soil multidimensional coupling bearing capacity boundary under the condition of considering the three-dimensional failure behaviors of the soil under the combined actions of the vertical force, the horizontal force and the bending moment. By fitting the failure parameters, the discrete failure parameters can be converted into an analytical expression with universality, so that the bearing capacity of the soil can be predicted under any load combi