考虑冻融循环的黄泛区公路路基含盐粉土动力损伤演化机理研究

This study takes the subgrade salty silt of the road in the Yellow River flood area as a research object. Based on laboratory tests and combined with CT scans, theoretical analysis and numerical simulation, the influence mechanisms of the freeze-thaw cycle and salinity on dynamic damage to the Yellow River area silt are studied from the angle of soil microscopic structure. The freeze-thaw cycle is implemented on the specimens in enclosed system with different contents of salt, and in each cycle the cyclic loadings are applied in freeze and thaw status in order to simulate the vehicle loads. After the freeze-thaw cycle, CT scans are implemented for analyzing the influence of the cycle and salinity on the micro-structure characteristics of the silt. Regular triaxial tests are applied to reveal the influence of the cycle and salinity on dynamic damages. Resonant-column tests and CT scans are taken on the soil samples to build a relationship between the micro-structure and shear wave velocity, and further establish a criterion of strength failure based on micro-structure characteristics expression. This project contributes to a deeper comprehension on the dynamic damage evolution of the Yellow River flood area salty silt subgrade under freeze-thaw cycle. It establishes a theoretical basis for the evaluation on subgrade dynamic stability, and facilitates the development of dynamics on this subgrade style.

以山东黄泛区公路路基含盐粉土为研究对象，拟基于室内试验，并结合CT扫描、理论分析与数值模拟等手段，从土细观结构损伤角度出发，研究冻融循环和盐分对黄泛区粉土动力损伤的影响机制。对不同含盐量试件进行封闭体系的冻融循环，每次循环中在冻结和融化状态施加循环荷载，用以模拟车辆荷载。冻融循环后对融土进行CT扫描，分析冻融和盐分对细观结构特征的影响规律。利用常规动三轴试验，揭示冻融循环作用和盐分对动力损伤的影响规律。对土样开展共振柱试验和CT扫描试验，建立细观结构特征与剪切波速的联系，进而建立基于细观结构特征表达的强度失效判别标准。项目研究有利于深入理解冻融循环作用下黄泛区含盐粉土路基动力损伤演化机理，为评价路基动力稳定性奠定理论基础，对黄泛区含盐路基土动力学的发展有促进作用。

以山东黄泛区公路路基含盐粉土为研究对象，基于室内试验，并结合核磁共振技术、理论分析与数值模拟等手段，从土细观结构损伤角度出发，研究冻融循环和盐分对黄泛区粉土动力损伤的影响机制。对不同含盐量试件进行封闭体系的冻融循环，每次循环中在冻结和融化状态施加循环荷载，用以模拟车辆荷载。冻融循环后对融土进行核磁共振技术，分析了冻融和盐分对细观结构特征的影响规律。利用常规振动三轴试验，揭示了冻融循环作用和盐分对动力损伤的影响规律。对土样开展共振柱试验和核磁共振测试，建立了细观结构特征与超声波波速的联系，进而建立基于细观结构特征表达的强度失效判别标准。项目研究有利于深入理解冻融循环作用下黄泛区含盐粉土路基动力性能演化机理，为评价路基动力稳定性奠定理论基础，对黄泛区含盐路基土动力学的发展有促进作用。