基于多尺度耦合的粗粒土附加应力响应机制及结构演变规律研究

As a material used frequently in the construction of hydraulic, civil and railway engineering, the coarse-grained soil is a typical dispersion pore medium with multi-scale structure. The settlement deformation under loads is an important problem that the engineering construction must pay attention to. In the present study, the stress and deformation of the coarse-grained soil are studied in the macroscopic phenomenological aspect, and the mechanisms of the stress transmission between the particles and the structure evolution are not disclosed deeply. The purpose of this project is to reveal in depth the stress response mechanism and structure evolution law of coarse-grained soil during settlement and deformation in different scale, and establish the analytical model of additional stress and the prediction model of settlement and deformation for coarse-grained soil. In this project, the static load test, Micro-CT scanning imaging technology, statics theory, probability theory and statistics theory are used to analyze by combining macro-meso-micro. It analyze the stress transfer process and the structure evolution process of soil during settlement and deformation in different scale. Therefore, the relationship between micro-mesoscopic characteristics and macro response of coarse-grained soil during settlement and deformation is expounded. The research results can effectively improve the prediction accuracy of settlement deformation and stability of coarse-grained soil and provide theoretical guidance and basis for practical engineering problems.

粗粒土作为水利、土木、铁道等工程建设常用的构筑材料，是一种典型的具有多尺度结构的散体孔隙介质，其在荷载作用下的沉降变形是工程建设必须关注的重要问题。现有研究大多从宏观唯像层面对粗粒土受力与变形展开研究，并未深入揭示土颗粒间荷载传递及其引起的结构演变机理。本项目拟以多尺度揭示粗粒土沉降变形过程中的应力响应机制及结构演变规律，并建立适用于粗粒土的附加应力解析模型及沉降变形预测模型为目标。为了实现该目标，将采用宏观-细观-微观相结合的分析方法，通过开展静载模型试验，利用Micro-CT扫描成像技术，结合静力学理论、概率理论、统计学理论，从不同尺度分析土体沉降变形的荷载传递过程及结构演变过程，阐明粗粒土沉降变形过程中土体微观和细观层面特性与宏观响应之间的内在联系。研究成果将能有效改善粗粒土沉降变形与稳定性的预测精度，为工程实际问题提供理论指导与依据。

粗粒土作为水利、土木、铁道等工程建设常用的构筑材料，是一种典型的具有多尺度结构的散体孔隙介质，其在荷载作用下的沉降变形是工程建设必须关注的重要问题。本项目首先基于PFC颗粒流数值分析软件揭示粗粒土沉降变形过程中的应力响应机制；其次基于弹性力学理论建立适用于粗粒土的附加应力解析模型；再次基于散体介质力学理论建立适用于粗粒土的沉降变形预测模型；最后通过开展静载模型试验，利用Micro-CT扫描成像技术，监测粗粒土沉降变形过程的荷载传递及结构演变，验证了本研究建立的粗粒土附加应力解析模型和沉降预测模型的合理性。研究成果将能有效改善粗粒土沉降变形与稳定性的预测精度，为工程实际问题提供理论指导与依据。