土工膜缺陷对土工膜心墙堆石坝工作性能的影响分析

Study on the Working Characteristics of Core Wall Rockfill Dam Considering Geomembrane Permeation

土工膜是土工膜心墙堆石坝的防渗体,土工膜缺陷会引起土工膜心墙堆石坝的渗透特征发生改变,导致坝体发生渗漏,坝体的工作性能亦受到较大影响。为研究土工膜出现缺陷后土工膜心墙堆石坝的工作性能,以某24 m高土工膜心墙堆石坝为例,采用数值模拟的方法,计算分析了缺陷大小、位置、数量及库水位变化等因素的影响。计算结果表明,缺陷高程在1/2库水位高度时,坝体的浸润线高度最高,渗流量最大;随着缺陷大小的增加,坝体内部浸润线高度及坝体渗流量均会增加;库水位的上升会导致坝体的渗流量及坝体内部浸润线增加,水位相同时不同的上升速率渗流计算结果基本一致;坝体的变形特征受单个土工膜缺陷的影响较小,与无土工膜缺陷变形量差距不足1 cm;土工膜缺陷出现会导致坝体稳定性减小。

The occurrence of geomembrane defects will cause the permeability characteristics of geomembrane core wall dams to change,resulting in leakage of the dam body,and the working characteristics of the dam body will be greatly affected.In order to study the working characteristics of the geomembrane core wall dam after geomembrane defects,numerical simulation methods were used to study the influence of the size,location,quantity and reservoir water level of the defects by taking a geomembrane core wall rockfill dam with 24 m height as a example.The results show that the defects in the middle section of the dam body have the most unfavorable impact on the dam body.The size of the defect also has a greater influence on the seepage characteristics of the dam,but the degree of influence is less than that of the defect location.The rise of the reservoir water level will increase the seepage flow of the dam body and the infiltration line inside the dam body.The deformation characteristics of the dam body are less affected by the individual geomembrane defects,and the horizontal displacement of the dam body is the largest in the absence of geomembrane defects.