榆林李家梁水库砂坝渗流安全及成因分析

榆林市李家梁水库砂坝自工程蓄水以来存在严重的渗漏安全隐患,为保障工程安全运行,通过水库历史资料数据分析和二维有限元渗流场计算,对该水库砂坝渗流安全及成因进行了深入的分析。结果表明:目前条件下大坝坝体防渗系统虽然满足运行要求,但左岸地下水位高,绕渗情况较严重。大坝左坝肩及坝基多个深度范围内存在中砂夹层以及水坠砂坝施工充填过程中导致坝体颗粒分布不均是造成坝后渗漏的主要原因。根据有限元渗流场计算结果,获得不同部位最大渗透坡降,各计算工况下排水渠底部渗透坡降在0.189～0.241,大于坝基土允许渗透坡降0.125,在库水位升高后,将使下游挟砂渗漏加剧,导致坝体破坏。因此,大坝除险加固需根据计算结果延长渗径,降低下游渗透坡降,保障大坝安全运行。

Seepage safety and cause analysis of Lijialiang sand dam reservoir, Yulin

The Lijialiang Reservoir sand dam in Yulin City has serious leakage safety hazards since the project water storage. In order to ensure the safe operation of the project, the reservoir sandstone dam seepage safety and its causes are analyzed through reservoir historical data analysis and two-dimensional finite element seepage field calculation. In-depth analysis. The results show that although the dam body anti-seepage system meets the operational requirements under the current conditions, the groundwater level on the left bank is high and the seepage is serious. The uneven distribution of granules in the mid-sand and the dam foundation during the filling process of the dam abutment and the dam foundation are the main causes of leakage behind the dam. Under each calculation condition, the osmosis slope at the bottom of the drainage channel is 0.189~0.241, which is greater than the allowable osmosis slope of the dam foundation soil by 0.125. After the reservoir water level rises, the downstream shale sand leakage will be intensified, resulting in dam failure.