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在底部可测孔压的固结仪内进行单面排水固结试验时,观测到试样底部的孔压可出现滞后现象。为分析其原因,考虑加载引起的动力效应,建立以竖向应变为求解对象的一维动力固结方程,并用有限差分法进行求解。引入新指标CD来综合考虑试样压缩模量、渗透系数、密度以及土样厚度等4个参数对动力效应的影响,探讨了该指标对固结过程中孔隙水压力的影响。计算结果表明,瞬时加载引起的动力效应是引起试样内孔压滞后的一个原因,并且对于压缩模量或渗透系数较大的试样,更易出现孔压滞后现象,同时动力效应对固结度的影响则主要体现在固结的前期。最后讨论了固结分析时可以忽略动力效应的范围。
The pore pressure at the bottom of the sample can be observed as a hysteresis when single-side drainage consolidation test is carried out in the consolidation instrument with pore pressure test at the bottom. In order to analyze the reason and consider the dynamic effect caused by loading, a one-dimensional dynamic consolidation equation with vertical strain as the object to be solved is established and solved by the finite difference method. The new index CD was introduced to comprehensively consider the effects of four parameters such as compressive modulus, permeability coefficient, density and soil thickness on the dynamic effect, and the effect of this index on the pore water pressure in the consolidation process was discussed. The calculation results show that the dynamic effect caused by instantaneous loading is one of the causes of the hysteresis of the inner bore of the specimen, and the pore pressure hysteresis is more likely to occur in the specimens with larger compressive modulus or permeability coefficient. Meanwhile, the dynamic effect on the degree of consolidation The impact is mainly reflected in the consolidation of the early. Finally, the range of dynamic effects that can be neglected in the consolidation analysis is discussed.