倾斜场地中逆断层错动对上覆土体影响的模型试验研究

MODEL TESTING STUDY ON THE INFLUENCE OF REVERSE FAULTING ON OVERLAYING SOIL UNDER AN INCLINED GROUND

  • 摘要: 基于设计的断层错动装置和PIV技术,研究了倾斜场地条件下逆断层错动导致上覆土体破裂的过程,重点分析了场地倾斜对破裂带的扩展规律、土体变形和地表变形等的影响。研究结果表明:随着场地倾斜程度增大,破裂带露头时的基岩错动位移也随之增大;不同倾斜场地的破裂带露头倾角均与Rankine理论预测结果更为一致,而Roscoe理论和Vermeer理论的预测结果均有较大误差;断层错动过程中上盘土体应变(剪应变、正应变和等效应变)均大于下盘土体;随着地表倾斜程度增加,露头时刻地表位移和地表位移梯度均随之增大;同时,结合现场实测数据,对建构筑物与断层的避让距离的研究表明:相较于下盘,上盘地表建构筑物的断层避让距离应更大;而随着场地倾角由正变为负,上盘地表建构筑物的避让距离还应增大。

     

    Abstract: Based on the faulting model test device designed by us and the PIV technique, the rupture process of overlaying soil due to reverse faulting under an inclined ground is studied. The emphasis of the study is put on the influence of surface inclination on the law of faulting rupture propagation, the deformation of soil and surface, etc. The study results show that the bedrock displacement increases with the inclining degree of the surfaces. The propagation angles of ruptures near the ground surfaces are more consistent with the predictions of Rankine theory for different grounds, while the predictions of Roscoe theory and Vermeer theory exhibit larger errors. The shear strain, normal strain and equivalent strain of the soil on the hanging wall are all larger than those on the foot wall during reverse faulting. The displacement of the bedrock has positive influence on the soil displacement and the displacement gradient with the inclining degree of the surfaces. Combined with field test data, the studies on the protection distance of the buildings and structures from the fault show that the protection distance of the buildings and structures on the hanging wall should be larger than those on the foot wall. When the surface inclination angle changes from positive to negative, the protection distance of the buildings and structures on the hanging wall should increase accordingly.

     

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