非均质土体中渗流场的非平稳随机模拟

将渗透系数作为对数正态非平稳随机场，分解为确定性趋势和平稳性扰动两部分，采用基于随机场Karhunen Loeve展开和摄动分析的KLME随机数值方法，探讨参数场的连续型线性趋势和间断型趋势项对渗流场统计特征的影响。分析表明，水头均值和标准差的空间分布受到参数场趋势性变化的影响，随线性趋势的变化方向而呈不同分布，线性趋势的斜率增大，水头统计矩的二阶修正项的作用也增大，在参数场间断型趋势条件下，水头统计矩呈复杂的非规则空间分布。

Nonstationary Stochastic Modeling of Seepage Field in Heterogeneous Soil

Random field model is adopted for soil permeability, which is decomposed into deterministic trend and stationary perturbation. The KLME method based on the combination of Karhunen Loeve expansion of random field and perturbation analysis is introduced to investigate the effect of continuous and discontinuous trend in log permeability field on statistics of seepage field. The result shows that the distribution of mean and standard deviation of hydraulic head is influenced by the change of trend, which is related to the linear trending direction, the contribution of second order correction of mean head and its standard deviation is enhanced with the increase of slope of linear trend, and under the condition of the discontinuous trend, the statistics of hydraulic head presents the irregular spatial distribution.