考虑渗透系数空间变异性的超高心墙堆石坝渗流分析

Seepage Characteristics Analysis of Super-high Core Rockfill Dam Considering Spatial Variability of Hydraulic Parameters

为探究超高心墙堆石坝多组防渗材料空间变异性对渗流安全的影响,根据建立的随机渗流分析模型,对某超高心墙堆石坝内多组防渗材料的渗透系数进行空间离散,系统研究坝体和坝基内渗流控制指标的演变规律。结果表明:心墙渗透系数的变异系数每增加0.1,其最大水力坡降的均值增大约9.8%,远高于帷幕灌浆和天然坝基。同时考虑基岩与帷幕灌浆的随机渗流特性后,帷幕前压力水头的最大值与仅考虑帷幕灌浆时增大了5%,坝基材料的空间变异性对帷幕灌浆渗流安全有一定影响。忽视防渗体的空间变异性,会高估防渗结构的渗流安全状态。

In order to analyze the influence of spatial variability of multiple impervious materials on seepage safety of super-high core rockfill dam,according to the established random seepage model,the seepage coefficient of multi-anti-seepage structure in super-high core rockfill dam is spatially discrete,and the seepage control index in the dam body and foundation is systematically analyzed.The results show that the mean value of the maximum hydraulic slope increases about 9.8%when the permeability variation coefficient of the caution wall increases by 0.1,which is much higher than curtain grouting and natural dam foundation.In addition,considering the random seepage characteristics of bedrock and curtain grouting,the maximum pressure water head before curtain grouting increases by 5%compared with only considering curtain grouting.The influence of spatial variability of dam foundation materials on the seepage safety of curtain grouting should not be ignored.The results show that the spatial variability of impervious body has adverse effects on seepage safety in both steady and unsteady seepage conditions.