忽略加载引起的动力效应可能是导致太沙基一维固结理论有时与固结试验结果相差过大的一个原因.对双面排水饱和地基,通过计入加速度项来考虑加载引起的动力效应,建立以竖向应变和孔隙压力为求解对象的一维动力固结方程组,并给出有限差分法数值求解格式,分析了动力效应系数对固结过程的影响.计算结果表明,动力效应对双面排水地基固结过程的影响比单面排水地基更加显著.在动力效应系数较大的地基中,孔压滞后现象比较明显,而在动力效应系数较小的地基中,孔隙压力累积较快,其极值有可能大于地面超载.另外,考虑动力效应时,在加载初期,双面排水地基的孔隙水压分布关于中间面并不对称,其固结速度要慢于厚度为其一半且单面排水地基的固结速度,更慢于太沙基一维固结理论值.%There exists an obvious discrepancy between the solution of one-dimensional consolidation of saturated soil layers based on Terzaghi' s theory and the observation in oedometer test,which can be a certain extent ascribed to the dynamic effect caused by loading which is taken no account of in the consolidation analysis.For a saturated soil layer with two-way drainage,the acceleration term is introduced to take into account of the dynamic effect that due to instantaneous loading,an equation set of one-dimensional dynamic consolidation which the vertical strain and the pore water pressure are set as its dependent variables is presented,and the numerical analysis is performed using the finite difference method.Then the influence of the coefficient of dynamic effect on the consolidation process is investigated.The numerical results show that the dynamic effect has a more noticeable effect on the consolidation process of the layer with two-way drainage than that with one-way drainage.There obviously exists a delay of pore water pressure in the layer with a greater factor of dynamic effect,while the pore water pressure in the soil layer with a less factor of dynamic effect increases rapidly and even its maximum value is perhaps greater than the value of loading.In addition,in the early period of consolidation,the distribution of pore water pressure of the layer with two-way drainage considering the dynamic effect is not symmetrical for the center of the layer,and the calculated value of its consolidation rate is less than that of the layer with one-way drainage and half the thickness of the former considering the dynamic effect,therefore it is much less than that based on Terzaghi ' s one-dimensional consolidation theory.
展开▼
