初始中主应力系数对中密粉煤灰动模量阻尼比影响的试验研究

Experimental study on effect of initial intermediate principal stress coefficient on dynamic shear modulus and damping ratio of medium-dense fly ash

利用土工静力-动力液压三轴-扭转多功能剪切仪,开展了在三向非均等固结状态下的饱和中密粉煤灰循环扭剪试验。着重探讨了初始中主应力系数对饱和中密粉煤灰的动模量和阻尼比特性的影响。试验结果表明:初始中主应力系数对粉煤灰动剪切模量有一定的影响,对阻尼比没有影响。根据仪器量测系统的特点,采用了大小位移计联合测量角位移的方法,不仅能够提高测试精度,而且能够获得完整的动模量和阻尼比随动剪应变幅值的变化过程。

The soil static and dynamic universal triaxial and torsional shear apparatus recently facilized in Dalian University ot Technology is employed to perform experimental tests on flyash with relative density of Dr = 60 % under three-directional anisotropic consolidation subjected to cyclic torsional shear loading. Through a series of soil tests, the effects of initial intermediate principal stress coefficient on dynamic shear modulus and damping ratio of medium-dense fly ash are investigated systematically. Based on the specialty of the apparatus, not only the precision of experiment can be improved by using the small angle displacement sensors and large angle displacemem sensor installed in the triaxial cell, but also the whole changes of dynamic modulus and damping ratio with amplitude of dynamic shear strain can be obtained continuously.