考虑非达西流的弱透水层固结计算

Consolidation computation of aquitard considering non-Darcy flow

由于成岩作用的影响,深部弱透水层中的黏性土较为坚硬、致密,在这种黏土层中的孔隙渗流规律有偏离达西定律的现象,而在现有的地面沉降研究中,对深部弱透水层的固结变形计算始终沿用以达西定律为基础的固结方程进行,这显然是与实际情况不相符的。鉴于此,以孔隙渗流为非达西流为基础,对太沙基一维固结方程进行了重新推导,并采用半解析法对非达西流-太沙基一维固结方程进行了求解。分别采用达西流-太沙基固结方程和非达西流-太沙基固结方程对同一固结问题进行了计算,结果表明,考虑非达西流后土层达到某一固结度所需的固结时间较之不考虑非达西流时明显增加了,而且固结时间增长的趋势与实测的增长趋势较为一致。

In the deep aquitard, the clay soil was stiff and compact for the diagenesis. The flow of pore water in these clay soil layers may not obey Darcy＇s flow. But the consolidation computation of deep aquitard still utilizes these consolidation equations that based on Darcy＇s flow. In order to improve the precision of consolidation computation of deep aquitard, Non-Darcy flow （described by the threshold gradient it and exponent m） was incorporated in the one-dimensional consolidation equation of Terzaghi. And semi-analysis was used to solve non-Darcy flow one-dimensional consolidation equation of Terzaghi. A consolidation case was computed by Darcy and non-Darcy flow one-dimensional consolidation equation of Terzaghi respectively; and the authors found that （1） for the special degree of consolidation, the consolidation time would increase when non-Darcy flow was considered; （2） The calculation results of non-Darcy flow consolidation equation were consistent with the measured values.