动态围压下空心圆柱扭剪仪模拟主应力轴旋转应力路径能力分析

针对英国GDS公司动态空心圆柱扭剪仪（HCA）在主应力轴旋转试验中能够实现三向动态加载（轴力、扭矩、内围压或外围压）的功能，通过严格的数学推导，提出了3种易于实现又与实际工程背景相符合的应力路径加载方式。当三向动载满足相应的条件时，可以实现（1）平均主应力p和剪应力幅值q保持恒定的应力路径（应力路径1）；（2）中主应力参数b = 0.5、剪应力幅值q为常数的应力路径（应力路径2）；（3）平均应力p保持不变、主应力旋转角90º突变的应力路径（应力路径3），其中应力路径1、2为模拟海洋波浪荷载作用下的应力路径试验提供了理论依据，应力路径3可用于模拟地震荷载作用下的土体动力特性。以上3种应力路径均不能在两向动态HCA仪中实现

Analysis of capabilities of HCA to simulate stress paths for principal stress rotation under dynamic confining pressure

According to the function that GDS dynamic hollow cylinder torsional apparatus can apply three-dimengional dynamic loads, namely axial load, torque and one of inner and outer pressure, three possible stress paths those coincided with practical engineering backgroud are presented by exactly mathematical derivation. When the three-dimengional dynamic loads meet some corresponding requirements, the following paths can be realized, ①the stress path which the mean principal stress p and shear stress q are kept constant; ②the stress path that the shear stress q is kept constant when the effect of intermediate principal stress b equals to 0.5; ③the stress path that the mean principal stress p is kept constant when the mutation of which is the rotation of maximan principal stress relative to the vertical direction is 90º. In addition, the first two paths provided theoretical foundation for experiment of simulating the stress paths under wave loading while the third path can be used to simulate the dynamic characteristics of soils subjected to earthquake load, and the three above stress paths can’t be realized in the HCA which with two dynamic loads