降雨诱发风化花岗岩残积土边坡渐进破坏的多尺度流固耦合理论与方法

Residual soils from the decomposed granite are popular in the south areas of China. Slope failures can be triggered by rainfall in the residual soils, and the occurrence of sliding destroyed properties, and even caused fatalities. After the field investigation and engineering geological survey of typical slopes in granite residual soils, the proposal firstly aims to analyze environmental factors for the occurrence of slope failures. Based on the detailed investigations, geological and mechanical models of slopes are then found for the analysis of failure modeling. In addition, databases of particle morphology are constructed to describe the geometry of typical particles in the residual soils. Lots of triaxial tests and numerical simulations can be conducted for the mechanical characteristics of residual soils, which consider typical particle morphology. The strength criterion can thus be made for the stress-strain characteristics of residual soils, which will be applied to analyze the progressive failure of typical slopes. Meanwhile, a series of model tests is conducted for slope failures in residual soils due to rainfall by digital image monitoring. Furthermore, the analysis is carried out for the mechanism of slope failures in the multi-scale coupling of seepage and stress fields through the combination of continuum and non-continuum mechanics. Finally, the evolution of slope failures in the residual soils can be completely understood, including the occurrence, deformation and progressive failure triggered by rainfall. The expected output will be comprehensive understanding in the progressive failure of residual soils through the innovation of the multi-scale coupling of fluid-solid interaction in soil mechanics.

风化花岗岩残积土在我国南方地区广泛分布，降雨诱发该类残积土边坡的变形破坏甚至滑坡灾害经常性发生。因此，本项目拟选取典型风化花岗岩残积土边坡为重点研究对象，结合详细的野外地质调查和工程勘察，剖析该类土质边坡变形破坏的影响因素，有效地构建其地质—力学模型，并探讨不同环境条件下边坡的变形破坏模式和机理；结合室内外实验和数值模拟试验，研究颗粒空间排列的不确定性和形貌特征差异性引起不规则颗粒的结构性力学特性变化，建立该类残积土介质强度准则和本构模型。借助现代数字图像处理，在室内降雨边坡模型实验结果分析的基础上，并结合典型风化花岗岩残积土边坡变形破坏特性，应用多尺度连续-离散流固耦合理论和数值模拟技术方法，进一步探讨不同尺度和环境条件下雨水入渗与土体中渗流特性对于边坡稳定性影响，系统研究滑坡孕育-变形-破坏全过程的演化规律，期待在降雨作用下残积土边坡渐进破坏多尺度分析的理论和方法上取得原创性研究成果。

本项目选取广东肇庆地区的花岗岩残积土为重点研究对象，在详细收集广佛肇高速和大潮高速公路工程地质勘察资料的前提下，剖析了高良和播植地区（广佛肇高速）和大潮高速公路典型路堑的类土质边坡变形破坏的影响因素，有效地构建其地质—力学模型，并探讨不同降雨环境条件下边坡的变形破坏模式和机理；结合室内外实验和数值模拟试验，研究颗粒空间排列的不确定性和形貌特征差异性引起不规则颗粒的结构性力学特性变化，建立该类残积土介质强度准则和本构模型。借助现代数字图像处理，在室内降雨边坡模型实验结果分析的基础上，并结合花岗岩残积土边坡变形破坏特性，应用多尺度连续-离散流固耦合理论和数值模拟技术方法，进一步探讨不同尺度和环境条件下雨水入渗与土体中渗流特性对于边坡稳定性影响，特别是残积土参数变异条件下，系统研究滑坡孕育-变形-破坏全过程的演化规律，在降雨作用下残积土边坡渐进破坏多尺度分析的理论和方法上取得了原创性研究成果。