基于复合土工膜防渗的希尼尔水库大坝渗流分析

Seepage Flow Analysis of Xini'er Dam Based on Composite Geomembrane Seepage Control

以希尼尔水库大坝复合土工膜防渗段为例,对主坝典型断面2+600、3+125与3+375断面进行了渗流分析,结果表明:主坝2+600断面坝基在高库水位时渗压水位较低、渗透压力较小,坝基渗流位势较小、变化正常,水平向渗透坡降小于允许值;主坝3+125断面坝基透水性较强,坝基复合土工膜与坝体PE复合土工膜组成的防渗体系防渗效果不佳,应加强渗流观测,确保大坝安全;主坝3+575断面坝基及坝体渗流位势变化基本正常,坝体砂砾石渗透坡降小于允许值,坝基透水性较强,在高库水运行期坝基渗压水位高、渗透压力较大。研究结果为指导水库的安全运行提供了重要参考。

Taking the composite geomembrane seepage control section of the Xini＇er dam as an example, the seepage flow of the typical main dam sections numbered 2＋600, 3＋125 and 3＋375 was analyzed respectively. The analysis results show that when the reservoir level is high, the main dam section 2＋600 is characterized by low seepage pressure water level, low seepage pressure, low dam foundation seepage potential, normal variation and horizontal seepage gradient being less than the allowable value while the main dam section 3＋125 is characterized by high dam foundation permeability and poor effect of seepage control by the seepage control system composed of dam foundation composite geomembrane and dam body PE composite geomembrane. It is necessary to strengthen seepage flow observation to ensure safety of the dam, and that as for the main dam section 3＋375, the variation of seepage flow potential of both the dam foundation and the dam body is basically normal, the seepage gradient of the dam sand and gravel is less than the permissible value, the dam foundation permeability is high and its seepage pressure water level and seepage pressure are both high when the dam is operated at a high reservoir level. The study results give an important reference for guiding safe operation of the reservoir.