CN-122016485-A - Method for simulating and judging humidification deformation coefficient of undisturbed loess

CN122016485ACN 122016485 ACN122016485 ACN 122016485ACN-122016485-A

Abstract

The invention provides a method for simulating and judging an undisturbed loess humidifying deformation coefficient, which relates to the technical field of geotechnical engineering, and comprises the steps of adding a structure reinforcing component based on undisturbed loess in a target area, preparing artificial structural loess meeting preset conditions and serving as a simulation sample; and respectively carrying out humidification deformation tests on the simulation samples with different water contents under multistage pressure loads, recording and determining humidification deformation coefficients according to deformation stability heights before and after humidification, and constructing a loess humidification deformation function model by taking the water contents and the pressure loads as independent variables and the humidification deformation coefficients as dependent variables. The invention can measure the humidification deformation of loess in the unsaturated state, and has practical applicability and prediction accuracy.

Inventors

ZHOU HENG
CAO YUNXIANG
ZHANG YAO
LI ZUFENG
Shang haixing
CHEN SIYUAN
XI YU
ZHOU RENWEI
XU FU

Assignees

中国电建集团西北勘测设计研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (10)

1. A method for simulating and determining a humidifying deformation coefficient of undisturbed loess, comprising: Adding a structural reinforcing component based on undisturbed loess in a target area, preparing artificial structural loess which meets preset conditions and taking the artificial structural loess as a simulation sample, wherein physical mechanical indexes and collapse coefficients of the artificial structural loess which meet the preset conditions and the physical mechanical indexes and collapse coefficients of the undisturbed loess meet corresponding preset similarity; Respectively carrying out a humidification deformation test under multistage pressure load on the simulation samples with different water contents, recording and determining a humidification deformation coefficient according to the deformation stability height before and after humidification, wherein the humidification deformation coefficient is used for representing the deformation response of loess with the increase of the water content after the pressure load is applied in a non-saturated state; Constructing a loess humidifying deformation function model by taking the water content and the pressure load as independent variables and the humidifying deformation coefficient as a dependent variable; Comparing the actually measured humidifying deformation coefficient with a predicted value of the loess humidifying deformation function model, judging whether the model is qualified in verification and obtaining the loess humidifying deformation function model which is qualified in verification if the relative error of the actually measured humidifying deformation coefficient and the predicted value of the loess humidifying deformation function model meets the preset requirement, wherein the loess humidifying deformation function model which is qualified in verification is used for predicting the humidifying deformation coefficient of the undisturbed loess to be processed.
2. The method for simulatively determining the humidifying deformation coefficient of undisturbed loess according to claim 1, wherein the performing the humidifying deformation test under the multistage pressure load on the simulative samples with different water contents respectively, recording and determining the humidifying deformation coefficient according to the deformation stability height before and after humidification comprises: respectively carrying out consolidation tests under multistage pressure loads on the simulation samples with different water content gradients according to the set water content gradients and the multistage pressure loads; Recording the stable deformation height of the simulation sample under the pressure load of each stage, and determining the humidifying deformation coefficient according to the stable deformation height corresponding to the gradient of the water content of the adjacent two stages under the same pressure load.
3. The method for determining the humidification deformation coefficient of undisturbed loess according to claim 2, wherein the determining the humidification deformation coefficient according to the height after the deformation corresponding to the gradient of the water content of the adjacent two stages under the same pressure load is stabilized comprises: determining the humidification deformation coefficient based on the following formula: =( )/ ; Wherein: representing the humidification deformation coefficient; Representing the height of the current soil sample with the water content gradient after the soil sample is subjected to deformation stabilization corresponding to soaking and humidification under the set level pressure; the soil sample representing the gradient of the water content of the next stage is subjected to the deformation stabilization corresponding to the soaking and humidification under the set stage pressure; Representing the original height of the soil sample.
4. A method for determining a loess humidification deformation coefficient as set forth in any one of claims 1 to 3, wherein said constructing a loess humidification deformation function model using said moisture content and said pressure load as independent variables and said humidification deformation coefficient as a dependent variable includes: Based on the test result of the humidifying deformation test of the simulation sample, taking the water content and the pressure load as independent variables and the humidifying deformation coefficient as dependent variable, performing systematic classification and nonlinear fitting on the test data, and constructing a three-dimensional response curved surface model reflecting the stress-humidifying deformation-water content comprehensive effect; And performing nonlinear regression fitting on the three-dimensional response curved surface model, and establishing the loess humidifying deformation function model for representing the comprehensive influence of the pressure load and the water content on the humidifying deformation coefficient.
5. The method for simulating and determining an undisturbed loess humidifying deformation coefficient according to claim 4, wherein the loess humidifying deformation function model is obtained by fitting a composite double exponential function, and the composite double exponential function is used for describing a nonlinear law of the influence of the water content and the pressure load on the humidifying deformation coefficient.
6. The method for modeling and determining a loess moisture deformation coefficient as in claim 5, wherein said loess moisture deformation function model is expressed by the following formula: ; Wherein, the Representing the coefficient of deformation of the humidification, The water content is indicated to be the water content, Representing the pressure load of the said pressure-bearing member, As the base intercept B, C, D, E, F, G, H are morphological parameters determined by nonlinear regression fit.
7. The method for determining an undisturbed loess moisturizing deformation coefficient by simulation according to any one of claims 1 to 3, wherein the performing a moisturizing deformation test on the undisturbed loess under the same test conditions as the simulation sample to obtain an actually measured moisturizing deformation coefficient, comparing the actually measured moisturizing deformation coefficient with a predicted value of the loess moisturizing deformation function model, if a relative error between the actually measured moisturizing deformation coefficient and the predicted value meets a preset requirement, determining that the model is verified to be qualified, and verifying that the qualified loess moisturizing deformation function model is used for predicting the moisturizing deformation coefficient of the undisturbed loess comprises: Verifying the loess humidifying deformation function model by using the undisturbed loess of the target area, performing the humidifying deformation test under the condition that the water content gradient and the pressure load are the same as those of the simulation sample to obtain actual humidifying deformation coefficients of the undisturbed loess under different working conditions, and inputting the same water content gradient and the pressure load into the loess humidifying deformation function model to obtain a model predicted value; comparing the actually measured humidification deformation coefficient under each working condition with the model predicted value to determine the relative error under each working condition; and if the relative errors corresponding to the pressure loads under all the water content gradients are smaller than a first preset threshold, judging that the loess humidifying deformation function model is qualified in verification.
8. The method for modeling and determining a wet deformation coefficient of loess as claimed in claim 7, further comprising: If the relative error corresponding to the pressure load is larger than or equal to the first preset threshold value under any water content gradient, judging that the loess humidifying deformation function model is unqualified in verification, re-screening the proportion of the artificial structural loess, returning to the step of preparing the artificial structural loess meeting preset conditions and serving as a simulation sample, until the relative error corresponding to each pressure load under all water content gradients is smaller than the first preset threshold value, and judging that the loess humidifying deformation function model is qualified in verification.
9. The method for determining a wet deformation coefficient of undisturbed loess by simulation according to any one of claims 1 to 3, wherein the preparing an artificial structural loess with physical and mechanical indexes and a collapse coefficient satisfying a corresponding preset similarity with undisturbed loess as a simulation sample by adding a structural reinforcing component based on undisturbed loess of a target region comprises: Sampling the undisturbed loess of the target area, preparing a plurality of groups of artificial structural loess doped with a structural reinforcing component by taking the physical and mechanical indexes of the undisturbed loess as references, and measuring the collapse coefficients of each group of artificial structural loess and the undisturbed loess under different pressure loads; respectively drawing a collapsible coefficient-pressure fitting curve of the artificial structural loess and the undisturbed loess under a set water content according to the collapsible coefficients under different pressure loads; Comparing the artificial structural loess with the physical and mechanical indexes of the undisturbed loess, and screening out the artificial structural loess with the physical and mechanical indexes meeting a first preset similarity; Comparing the screened collapsibility coefficient-pressure fitting curve of the artificial structural loess under the set water content with the collapsibility coefficient-pressure fitting curve of the undisturbed loess under the same water content, and selecting the artificial structural loess with the collapsibility coefficient-pressure fitting curve meeting a second preset similarity as the simulation sample.
10. The method for simulatively determining the wet deformation coefficient of undisturbed loess according to claim 9, wherein the selecting an artificial structural loess whose wet deformation coefficient satisfies a second preset similarity as the simulative sample by comparing the screened artificial structural loess wet deformation coefficient-pressure fitting curve under the set moisture content with the wet deformation coefficient-pressure fitting curve of undisturbed loess under the same moisture content comprises: Comparing the screened collapsibility coefficient-pressure fitting curve of the artificial structural loess under the set water content with the collapsibility coefficient-pressure fitting curve of the undisturbed loess in a morphological mode, and determining a first error between the collapsibility coefficient-pressure fitting curve and the collapsibility coefficient-pressure fitting curve; And when the first error is smaller than a second preset threshold value, judging that the similarity between the screened collapsibility coefficient-pressure fitting curve of the artificial structural loess and the collapsibility coefficient-pressure fitting curve of the undisturbed loess meets the second preset similarity, and taking the corresponding artificial structural loess as the simulation sample.

Description

Method for simulating and judging humidification deformation coefficient of undisturbed loess Technical Field The invention relates to the technical field of geotechnical engineering, in particular to a method for simulating and judging an undisturbed loess humidifying deformation coefficient. Background Loess is a fourth sediment, has different morphology and composition from other soils, has physical characteristics of high pore ratio, low density, high soluble salt content and the like, is widely focused on due to unique causative mechanism, mineral composition and mechanical properties, and has obvious compressibility under the coupling action of multiple factors such as soaking, loading and the like, so that the foundation is easy to be partially collapsed, collapsed and deformed, and great difficulty is brought to practical engineering. In the related art, the loess collapsibility evaluation is mainly based on a collapsibility coefficient specified in a collapsible loess area building standard, the coefficient is obtained by measuring the deformation amount of a sample after soaking saturation, however, for loess in an unsaturated state or other complex working conditions, the related art is difficult to accurately measure and evaluate the deformation of collapsible loess in a humidifying process, especially in an unsaturated state, and the unsaturated soil mechanical test has the advantages of complex operation, long period, high cost and difficult popularization, in addition, the physical mechanical property and the collapsibility characteristic of the natural loess have obvious fluctuation due to the difference of deposition environments, and the representativeness and the repeatability of the test result are poor. Disclosure of Invention The invention aims to solve at least one technical problem that the humidity deformation in the unsaturated state is difficult to accurately measure, the unsaturated soil mechanics test is complex in operation and high in cost, the representativeness and the repeatability of the test result are poor due to the difference of the deposition environment of natural loess, and the like. In order to solve the above problems, the present invention provides a method for simulation determination of an undisturbed loess humidifying deformation coefficient, comprising: Adding a structural reinforcing component based on original loess of a target area, preparing artificial structural loess which meets preset conditions and taking the artificial structural loess as a simulation sample, wherein physical mechanical indexes and collapse coefficients of the artificial structural loess which meet the preset conditions and the physical mechanical indexes and collapse coefficients of the original loess meet corresponding preset similarity; Respectively carrying out a humidification deformation test under multistage pressure load on the simulation samples with different water contents, recording and determining a humidification deformation coefficient according to the deformation stability height before and after humidification, wherein the humidification deformation coefficient is used for representing the deformation response of loess with the increase of the water content after the pressure load is applied in a non-saturated state; Constructing a loess humidifying deformation function model by taking the water content and the pressure load as independent variables and the humidifying deformation coefficient as a dependent variable; Comparing the actually measured humidifying deformation coefficient with a predicted value of the loess humidifying deformation function model, judging whether the model is qualified in verification and obtaining the loess humidifying deformation function model which is qualified in verification if the relative error of the actually measured humidifying deformation coefficient and the predicted value of the loess humidifying deformation function model meets the preset requirement, wherein the loess humidifying deformation function model which is qualified in verification is used for predicting the humidifying deformation coefficient of the undisturbed loess to be processed. Optionally, the performing a humidification deformation test on the analog samples with different water contents under a multi-stage pressure load, and recording and determining the humidification deformation coefficient according to the deformation stability height before and after humidification includes: respectively carrying out consolidation tests under the multistage pressure load on the simulation samples with different water content gradients according to the set water content gradients and the multistage pressure load; Recording the stable deformation height of the simulation sample under the pressure load of each stage, and determining the humidifying deformation coefficient according to the stable deformation height corresponding to the gradient of the water content of the