振动频率对饱和黏土动力特性的影响

为了了解振动频率对饱和黏土动力特性的影响,针对天津临港工业区典型黏土做了一系列原状土与重塑土的动力试验.结果表明,随着频率的增加,原状土变形曲线由破坏型向发展型再向渐稳型过渡,重塑土变形曲线多为直线型.对4种动变形曲线定义了不同的破坏标准,发现随着振动频率的增加,软黏土动强度的变化趋势为先提高,之后增长幅度减小.频率越低,原状土的孔压升高越快;但振动频率对于重塑土孔压发展影响较小,原状土的界限孔压比低于重塑土.振动频率越低,原状土的动弹性模量软化指数下降得越快,并最终稳定在界限软化指数;不同振动频率下,重塑土软化指数的发展较为一致.

Contrastive Study on the Dynamic Characteristics of Saturated Clay in Different Vibration Frequencies

A few dynamic tests are carried out to study the influence on dynamic characteristics of the undisturbed and remolded clay in Lingang industrial area of Tianjin under different vibration frequencies. The test results show that, with the increasing of vibration frequency, the axial strain curves development mode of the undisturbed clays transforms from destructive mode to development-oriented mode, then to the stable one, and that most of the axial strain curves of remolded silty clay are lineal. Failure criteria are defined for four different axial strain curves as the following： as the frequency increases, dynamic strength of both undisturbed and remolded silty clay increases rapidly at the beginning, and then the increase slows down. The lower the frequency is, the more rapidly the pore pressure of undisturbed silty clay goes up, but the vibration frequency has little influence on pore pressure development of the remolded, and the pore pressure ratio limit of the undisturbed is lower than that of the remolded. The lower the frequency is, the faster the soften ratio of undisturbed silty clay goes down. No matter what the vibration frequency is, it will always stable at the softening ratio limit in the end. For the remolded silty clay, the softening ratio curves have a similar tendency under different vibration frequencies.