循环荷载下重塑饱和粉黏土的动—静强度弱化规律研究

Study on dynamic static strength degradation of remolded saturated silty clay under cyclic loading

选取重塑粉质黏土作为试验土样,采用室内动静三轴试验系统研究循环荷载作用下土体的动静力学特性,动静强度的弱化规律,考虑了围压、频率、固结比、动应力比、循环次数5种因素对动静强度的影响。试验结果表明:承受循环荷载作用后土体与原土体相比总强度可能会增加也可能会降低,剪切时的孔压都会大于原土剪切时孔压。可以统一的是所有承受循环荷载作用后土体有效强度都会降低。通过对强度进行无量纲化处理,引入了动弹性应变和动弹性孔压,确定了动弹性应变与有效强度比,动弹性孔压与有效强度比关系符合指数模型,并提出来适用于衰减系数与动弹性应变,衰减系数与动弹性孔压的对数函数模型。

In this paper we select restore silty clay as test soil samples, investigate dynamic and static mechanical properties of soil mass under circulating load, and static strength weakening of law by using the indoor static triaxial test system, and take into account the confining pressure, consolidation ratio, frequency and dynamic stress ratio and cyclic number five factors＇influence on static strength. The experi- ment shows that compared with the original soil of soil under cyclic loading total strength may increase or reduce, and the pore pressure at the time of shearing will be larger than the pore pressure at the time of shearing. It can be unified that all effective strength of soil under cyclic loading are reduced. The dynam- ic elastic strain and dynamic elastic pore pressure are introduced through the dimensionless treatment of strength. The dynamic elastic strain and effective strength ratio are determined. The relationship between dynamic elastic pore pressure and effective strength ratio accords with exponential model, and it is suit- able for the attenuation coefficient and elastic strain, attenuation coefficient and the logarithmic function of pore pressure dynamic elastic model.