砂土与结构界面单剪特性影响因素分析

疏排水沉降引起的竖直附加力导致了华东地区多个立井井筒破裂,为了有效地解决这一工程问题,通过单剪仪研究了竖直附加力的影响因素,在自行加工改造的高应力单剪仪试验系统上进行了饱和（干）粗砂、饱和（干）细砂与钢材及混凝土界面的正交试验.试验研究表明：砂的干湿状态对抗剪强度（竖直附加力的峰值）影响最大;砂的干湿状态,基底对初始剪切刚度的影响均较显著.颗粒破碎是砂的干湿状态、土性、基底三者对界面剪切特性影响的一个综合性反映.

Analysis about Effect Factors on the Shearing Characteristics of the Interface between Sand and Structures

Vertical additional force outside surface of the shaft lining caused by dewatering settlement of bottom aquifer in the thick alluvium induces shaft fracture in east China.In order to solve this engineering problem effectively,the influential factors of vertical additional force are studied by use of the simple shear apparatus.The orthogonal tests about interface between saturated/dry coarse sand,saturated/dry fine sand and steel/concrete are carried out at the manufactured,modified simple shear system.The testing result shows that the conditions(dry or saturated) have more significant effect on the shear strength than soil type or base,and the conditions(dry or saturated) and base are significant factors of initial shearing stiffness.Grain breakage is comprehensive reflection of influence from three factors on shearing characteristics of the interface.