静动应力作用下大连饱和黏土的剪切特性研究

A study on shearing behavior of saturated clay under action of static and dynamic stresses

针对人工制备的大连饱和黏土,在静应力与循环应力联合作用下进行了多组循环剪切试验,着重探讨了初始静力大小及加载速率对循环剪切变形特性的影响.试验表明静应力与循环应力作用下饱和黏土具有循环蠕变特性,总应变由初始静应变和循环蠕变两部分组成,其中循环蠕变主要受循环应力幅值、初始静应力大小及其加载速率的影响,循环蠕变的逐次增加量受循环应力幅值的变化影响最大。在对试验结果分析基础上,考虑初始静应力大小及其加载速率的影响,采用等效应力方法建议了循环蠕变经验关系式,并引入屈服面流变理论,建立了单调与循环荷载联合作用下的循环蠕变计算模型,3个模型参数易于通过循环剪切试验获得。

Many cyclic shear tests are performed on the saturated clay specimens prepared in Dalian under the action of static and cyclic stresses.The effect of the initial static stress magnitude and its loading rate on cyclic stress-strain relations is emphatically discussed,and then the constituents and its equation of general strain are analyzed.The testing data indicate that the general strain is constituted by two parts,the initial static strain and cyclic creep.The variation of cyclic creep is mainly affected by the cyclic stress amplitude and the magnitude and loading rate of initial static stress.But the cyclic stress amplitude is the most influential factor of the variation of cyclic creep.Based on the testing results,an experimental relation of cyclic creep is suggested by employing equivalent stress method,considering the magnitude and loading rate of initial static stress.Furthermore,the computational model of cyclic creep under the action of monotonic and cyclic load is established by introducing the rheological theory of yield surface.The model parameters are easy to obtain by performing cyclic shearing tests.