节理发育黄土陡坡在入渗作用下的滑塌机理研究

Vertical joints are extensively developed in the Loess area. The volume shrinkage in the loess under the dry condition leads to the opening of joint, which is the advantage of the seepage channel when the rainfall occurs. This problem often leads to the loess slope disasters. Because of the insufficient research on the seepage characteristics of loess joint, it is still difficult to consider the impact of joint when analyzing those loess slope disasters. In this project, based on experiments and theoretical analysis, the law of evaporation and shrinkage of loess will be revealed, evaluation method for increasing of joint aperture caused by shrinkage of loess will be established, the model of loess joint penetration considering the increasing of joint aperture will be established. Further, this model will be introduced into the seepage numerical calculation method, and the Develop loess joint infiltration model test will be carried out. The numerical calculation results and model test results of loess joint seepage are compared to verify and perfect the model of loess joint water infiltration.Based on the foregoing studies, the arid climatic conditions and rainfall conditions were simulated to determine the dynamic evolution process of the moisture field of loess steep slope under different joint development conditions. Finally, the results of the degradation of the loess by the combination of wetness revealed the slump mechanism of the loess steep slope in the process of infiltration. The research results are helpful to make up for the shortcomings of the current study on the nature of loess joint engineering. It is helpful to form a scientific analysis method of loess steep slope disease considering joint development.

黄土陡坡中垂直节理普遍发育。黄土在旱季蒸发收缩变形，使节理张开度增大而形成优势渗水通道。此时降雨入渗导致黄土陡坡滑塌破坏频发。因对黄土节理水分入渗机理研究不足，考虑节理影响尚无法分析此类滑塌破坏。本项目就此开展研究工作。基于试验和理论分析，揭示黄土蒸发收缩变形规律，建立黄土蒸发收缩变形引起的节理张开度增大的评价方法，考虑张开度建立黄土节理水分入渗模型。进一步将该模型引入数值计算方法中并开展黄土节理入渗模型试验，对比黄土节理入渗数值计算结果和模型试验结果，验证并完善所建立黄土节理水分入渗模型。在前述研究基础上，模拟干旱气候条件和降雨条件，研究确定不同节理发育工况下黄土陡坡水分场的动态演化过程。结合湿化使黄土强度劣化的成果，研究揭示节理发育黄土陡坡在入渗过程中的滑塌机理。研究成果有利于弥补目前黄土节理工程性质研究不足，有利于形成科学的考虑节理影响的黄土陡坡病害分析方法。

黄土陡坡中垂直节理普遍发育。黄土在旱季蒸发收缩变形，使节理张开度增大而形成优势渗水通道。此时降雨入渗导致黄土陡坡滑塌破坏频发。因对黄土节理水分入渗机理研究不足，考虑节理影响尚无法分析此类滑塌破坏。本项目就此开展研究工作。基于试验和理论分析，揭示了黄土蒸发收缩变形规律，建立了黄土蒸发收缩变形引起的节理张开度增大的评价方法，考虑张开度建立了黄土节理水分入渗模型。进一步将该模型引入数值计算方法中并开展了黄土节理入渗模型试验，对比黄土节理入渗数值计算结果和模型试验结果，验证并完善了所建立黄土节理水分入渗模型。在前述研究基础上，模拟干旱气候条件和降雨条件，研究确定了不同节理发育工况下黄土陡坡水分场的动态演化过程。结合湿化使黄土强度劣化的成果，研究揭示了节理发育黄土陡坡在入渗过程中的滑塌机理。研究成果有利于弥补目前黄土节理工程性质研究不足，有利于形成科学的考虑节理影响的黄土陡坡病害分析方法。