CN-116150847-B - Structural soil subgrade stability calculation method under rainfall infiltration condition

Abstract

The invention discloses a structural soil subgrade stability calculation method under rainfall infiltration conditions. Firstly, according to the change of the Euler number of the microscopic characteristics of structural soil filled in a roadbed after rainfall infiltration, the shearing strength of the structural soil of the surface layer roadbed is combined, and an evolution relation of the shearing strength of the structural soil along with infiltration time is established. And then according to the influence of the rainfall infiltration process on the strength of the structural soil, establishing an expression of the shear strength of the structural soil, which changes along with the infiltration time and the burial depth, and finally establishing a refined finite element calculation model to analyze the stability of the structural soil subgrade under the rainfall infiltration condition. According to the method, only a consolidation non-drainage triaxial test and a microscopic structure test are needed to obtain the shear strength index and the Euler number of the structural soil on the surface layer of the roadbed, and the shear strength index and the Euler number can be substituted into finite element software through simple calculation to calculate the stability of the rainfall infiltration structural soil roadbed.

Inventors

• TAN XIAOLEI
• ZHANG XUEYI
• LI KEKE
• XU JINGKUI
• FENG ZHUO
• ZHAO XUJIE
• YAO SHENGJIN
• CHENG JUNLI
• Cheng Cuijing
• XING CHENGWEI
• XU PENGPENG
• DU XINFENG
• YANG LIWEI
• ZHANG LIMING
• JIANG GUANGHUI
• LIU XUECAI
• CHANG YAJING
• LIU WEI
• SHAN HAO
• YU XIAOMING

Assignees

• 中建路桥集团有限公司

Dates

Publication Date

20260512

Application Date

20230214

Claims (3)

1. 1. The method for calculating the stability of the structural soil subgrade under the rainfall infiltration condition is characterized by comprising the following steps of: S1, measuring the cohesive force of the structural soil without infiltration of the surface layer by utilizing an indoor consolidation non-drainage shear test And internal friction angle Obtaining the normal stress of the non-infiltrated structural soil according to the molar coulomb theory Shear strength under the action of ; S2, taking the surface layer structural soil with rainfall infiltration time of T=0, T=t, T=2t and the number of Euler of the surface layer structural soil in the rainfall infiltration process by adopting a microstructure test method Wherein , And is an integer; s3, determining Euler number of the surface layer structural soil with different infiltration time according to the step S2 Calculating rainfall influence coefficient at infiltration time T And to the rainfall influence coefficient at the infiltration time T Fitting to obtain an expression thereof; s4, rainfall influence coefficient at the infiltration time T Expression for determining shear strength of surface structural soil at rainfall infiltration time T And the cohesive force at this time And internal friction angle ; S5, shearing strength of the surface structural soil according to rainfall infiltration time T As a result, the shear strength of structural soil with the vertical distance from the slope surface of the roadbed slope as the burial depth h at the infiltration T time is calculated And the cohesive force of structural soil of roadbed burial depth h in infiltration T time And internal friction angle ; S6, establishing a refined finite element calculation model, and calculating the stability of the structural soil subgrade under the rainfall infiltration condition; The shear strength of the surface structural soil at the rainfall infiltration time T in the step S4 Surface layer structural soil cohesive force during rainfall infiltration time T And the surface layer structural soil internal friction angle at rainfall infiltration time T The calculation formula is as follows: ; ; ; in step S5, the shearing strength of the structural soil with the vertical distance from the roadbed slope surface being the burial depth h at the infiltration T time Obtained by the following formula: , wherein, , ; The diffusion coefficient is in the range of , Is a blocking factor with a value range of ; In step S5, the structural soil with the burial depth h has cohesive force at the infiltration T time Obtained by the following calculation formula: , The internal friction angle of the structural soil with the burial depth h in the infiltration T time is obtained by the following calculation formula: 。
2. 2. The method for calculating the stability of a structural soil subgrade under a rainfall infiltration condition according to claim 1, in which the rainfall influence coefficient at the infiltration time T in step S3 The expression is obtained by the following substeps: S31, utilizing the formula Calculating the infiltration time T=0, T=t, T=2t once again, the rainfall influence coefficient at t=nt , wherein, Indicating the Euler number of the non-infiltrated structural soil, Representing the Euler number of the structural soil at the infiltration T time; s32, adopting And fitting a change rule of the rainfall influence coefficient along with the infiltration time T by the model, wherein T represents the infiltration time, and a and b are fitting undetermined coefficients.
3. 3. The method for calculating the stability of a structural soil subgrade under rainfall infiltration conditions according to claim 1, in which in step S6, said building a refined finite element calculation model comprises the sub-steps of: s61, calculating cohesive force and internal friction angle of structural soil with different infiltration time and different burial depths, and drawing a change curve; S62, calculating the buried depth when the cohesive force or the internal friction angle value is an integer when the rainfall infiltrates into the soil T, dividing the soil layer at the buried depth in parallel with the slope, and stopping dividing the soil layer when the thickness of the divided soil layer exceeds the roadbed filling height; s63, representing the shear strength index of the soil layer by using the average value of cohesive force or internal friction angle at the rainfall infiltration T at the layer interface and the previous layer interface.

Description

Structural soil subgrade stability calculation method under rainfall infiltration condition Technical Field The invention relates to the field of traffic engineering, in particular to a method for calculating stability of a structural soil subgrade under rainfall infiltration conditions. Background In order to solve the problem of unbalanced development, the construction key area of the highway engineering is gradually transferred from the coastal plain area with developed economy to the mountain hilly area with lagged economy, and the poor soil with strong structure is frequently encountered in the process. The natural clay can form a certain structural strength in the geological history process, but some clay has stronger structural property, such as Zhanjiang clay and the like, and the natural clay has the strength added by the structural property and has higher compression resistance, so that the natural clay can support heavy overlying load without further compaction and maintain a macroporous state. However, under the influence of rainfall infiltration, especially after heavy rainfall, the structural property of the soil body is destroyed after soaking, the soil body strength is obviously reduced, and the steep embankment filled by the structural soil is easy to generate collapse, sedimentation and other diseases. When the embankment filled with the structural soil is affected by rainfall infiltration, the structural soil intensity attenuation of the deep buried depth lags behind the structural soil intensity attenuation of the shallow buried depth, and meanwhile, the shear strength attenuation amplitude of the structural soil with different buried depths is obviously different. Many scholars and engineering technicians carry out beneficial researches on structural soil strength attenuation law, rainfall infiltration slope stability and the like in the soaking process by means of theoretical analysis, numerical simulation, experiments and the like. However, the existing theoretical analysis method generally needs to utilize theories such as penetration, unsaturated soil and the like to study the strength characteristics of embankment filling in the rainfall process, the influence of the soil body structure on the strength cannot be fully considered, the numerical simulation calculation method has high requirements on model establishment, calculation parameter selection and the like, and the test means needs more manpower and material resources. Meanwhile, the rainfall infiltration time and the burial depth influence factors are comprehensively considered, and the method for analyzing the stability of the structural soil subgrade is less. Therefore, the stability of the embankment slope is analyzed by researching the change rule of shear strength along with the infiltration time and the influence of the burial depth of the embankment structural soil under the rainfall infiltration condition and combining finite element numerical calculation software, so that a theoretical basis is provided for the design, construction and management of the structural soil subgrade, and great theoretical and practical significance is provided for the construction of highways and railways and the guarantee of the life and property safety of people. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a method for calculating the stability of a structural soil subgrade under a rainfall infiltration condition, which can simply and quickly calculate the stability of the structural soil subgrade under the rainfall infiltration condition. The invention aims to achieve the aim, and the aim is achieved by the following technical scheme: The method for calculating the stability of the structural soil subgrade under the rainfall infiltration condition is characterized by comprising the following steps of: s1, measuring the cohesive force of the structural soil without infiltration of the surface layer by utilizing an indoor consolidation non-drainage shear test And internal friction angleObtaining the normal stress of the non-infiltrated structural soil according to the molar coulomb theoryShear strength under the action of; S2, taking the surface layer structural soil with rainfall infiltration time of T=0, T=t, T=2t and the number of Euler of the surface layer structural soil in the rainfall infiltration process by adopting a microstructure test methodWherein,And is an integer; s3, determining Euler number of the surface layer structural soil with different infiltration time according to the step S2 Calculating rainfall influence coefficient at infiltration time TAnd to the rainfall influence coefficient at the infiltration time TFitting to obtain an expression thereof; s4, rainfall influence coefficient at the infiltration time T Expression for determining shear strength of surface structural soil at rainfall infiltration time TAnd the cohesive force at this timeAnd internal frictio