考虑应力水平的软土固结系数计算与试验研究

Calculation and experiment on consolidation coefficient for soft clay considering different stress levels

在固结度计算中通常将固结系数视为常数,实际上并非如此。通过研究软土固结系数在压缩过程中随应力水平变化的规律,推导出正常固结和超固结状态下固结系数与有效应力之间的表达式。在正常固结状态下,当应力水平小于在前期固结压力时,固结系数随应力水平的增加而增加;当超过前期固结压力后,固结系数随应力水平的增加而减小;在超固结状态下,固结系数随应力水平的增加而增加,在一定程度后趋于平稳。室内试验结果进一步说明了和验证固结系数这一特点。推导的固结系数与固结应力水平关系表达式是可行的,其计算值与试验结果的变化趋势一致,大小基本吻合,将其用于计算变形速率和固结度中,可提高准确性。

In the calculation of consolidation degree, the onsolidation coefficient Cv ,which varies with the effective stress during consolidation, is usually regarded as constant. The relationship between Cv and the effective stress of soft clay is researched and the expression between them is derived respectively. For normally consolidated soft clay, before the preconsolidation pressure, Cv increases with the effective stress; increase after the preconsolidation pressure, Cv decreases with the effective stress increase. For over-consolidated soft clay, Cv increases quickly with the effective stress at first, then the value of Cv either remains constant or increases moderately with the increasing effective stress increase. The results of several laboratory tests show that the expression presented is reasonable, which can improve the accuracy for the calculation of settlement rate and consolidation, degree.