循环荷载作用下江西重塑红黏土动力特性试验研究

Experimental Study on Dynamic Properties of Remolded Red Clay in Jiangxi under Cyclic Loading

以江西东乡县重塑红黏土为研究对象,在不同物态和应力状态下进行室内动三轴试验研究。主要研究在不同含水率和固结围压条件下,红黏土破坏动应力-破坏振次关系、动黏聚力和动内摩擦角、动应变-动弹性模量关系以及阻尼比的变化规律。试验结果表明:相同破坏振次条件下,高固结围压和低含水率能提高土破坏时的动强度。土的动黏聚力和动内摩擦角随着土样含水率的增加线性递减。红黏土动弹性模量随着轴向动应变的增加而减小,同时动弹性模量的减小幅度也越来越小,最后趋于平缓。相同轴向动应变条件下,高固结围压和低含水率土样的动弹性模量更大。拟合后的红黏土动本构关系符合Kondner双曲线模型。红黏土的阻尼比随着固结围压和含水率的增大而增大。

A series of indoor cyclic triaxial tests are carried out to study the dynamic properties of remolded red clay from Dongxiang county,Jiangxi.The experiment mainly studied the failure rule of red clay under different water content and consolidation confining pressure,including dynamic stress,failure relation,dynamic cohesion,dynamic internal friction angle,dynamic strain,dynamic elastic modulus and damping ratio.Results show that high consolidation confining pressure and low water content can increase the failure dynamic stress of soil under the same destructive vibration conditions.The dynamic cohesive force and dynamic internal friction angle of soil decrease linearly with the increase of soil moisture content.The dynamic elastic modulus of red clay decreases with the increase of the axial dynamic strain.Meanwhile,the slope become smaller,finally,tends to be slow.Soil under high consolidation confining pressure and low moisture content has high dynamic elastic modulus.The fitting dynamic constitutive relation of the red clay satisfies the Kondner hyperbolic model.The damping ratio of red clay increases with the increase of confining pressure and water content.