随机介质一维概率固结特性

基于土层剖面随机场理论,将土体固结系数cv模拟成服从对数正态分布的空间随机场,该随机场可以通过均值、变异系数、相关距离表示.利用Monte-Carlo方法对土体一维概率固结特性进行了分析,同时用一实例演示了所提方法的计算过程.结果表明:不考虑cv变异性的确定性固结分析过高地估计了实际土体的固结速率;超静孔压和固结度的标准差都对时间因数T的敏感性小,可以通过所提出的简便公式近似计算;当相关距离较大时,实际中可以不对cv的方差进行折减,相反,当相关距离较小时,推荐了方差折减系数的简便计算公式.该结论对固结系数变异性较大地区的实际工程建设具有指导意义,简便的方差计算方法能够有效地预测土体固结过程中的不确定性.

Characteristics of one-dimensional probahilistic consolidation of random media

Based on random field theory of soil profile,the characteristics of one-dimensional probabilistic consolidation are analyzed by Monte-Carlo simulation combined with the modeling coefficient of consolidation cv as a spatially lognormal distribution random field which can be described by the mean value,coefficient of variation and correlation distance.At the same time,a simple case for demonstrating the procedure of calculation of methodology is proposed.The results indicate that the deterministic solution,which neglects the variation of cv,overestimates the true rate of consolidation.The standard deviations of excess pore pressure and degree of consolidation are both insensitive to time factor Tv and can be approximately calculated by the recommended simple formulae.If the correlation distance is large,there is no necessity of standard deviation reduction of cv;whereas if the correlation distance is small,a convenient method of calculating the standard deviation reduction factor is recommended.The conclusions have guiding significance for engineering design or construction in the region that has high variation of cv and the proposed simple methodology can efficiently predict the variation in soil consolidation.