【摘要】 以西夏水库扩容改造工程为依托，针对水库场地的角砾基底，对其土工膜防渗结构方案进行评估.土工膜防渗结构方案设计包含土工膜厚度的确定和结构形式的选择两方面.影响土工膜厚度的直接因素有土工膜的防渗结构等级、与土工膜接触的最粗粒组的最小粒径、土工膜承受的水压力、土工膜的允许拉应力、土工膜的弹性模量，因为土工膜的允许拉应力和弹性模量与水温有关，所以水温是影响土工膜厚度的间接因素.土工膜防渗结构形式的选择应满足工程现场需要，库区可采用土工布-土工膜-土工布分离式，而坝坡宜采用土工布-土工膜-土工布的复合式.在土工膜与刚性结构的连接部位宜增设GCL垫层，在膜下应设置排气盲沟.土工膜防渗结构方案的合理性应通过水库的渗漏量进行评估.扩容改造后的西夏水库在试蓄水后围堤外侧坝坡干燥，集渗廊道内监测水位无异常，虽然在输水塔涵附近监测到的日渗漏量为17～112 m~3，但综合评估认为，该水库的土工膜防渗结构方案设计合理，且土工膜的施工质量总体较好.更多还原

【Abstract】 Based on the expansion and reconstruction project of Xixia Reservoir,the geomembrane impermeable structure scheme is evaluated for the angular gravel substrate of the reservoir site. The design of the geomembrane impermeable structure scheme consists of the determination of the geomembrane thickness and the selection of the structure form. There are many direct factors affecting the geomembrane thickness,such as the anti-seepage structure grade of the geomembrane,the minimum particle size of the coarsest grain group in contact with the geomembrane,the water pressure on the geomembrane,the allowable tensile stress of the geomembrane,and the elastic modulus of the geomembrane. Because the water temperature is related to the allowable tensile stress and the elastic modulus of the geomembrane,the water temperature is an indirect factor affecting the thickness of the geomembrane. The selection of geomembrane anti-seepage structure form should meet the needs of the project site.The separation type of geotextile-geomembrane-geotextile can be adopted in the reservoir basin,and the composite type of geotextile-geomembrane-geotextile should be adopted in the dam slope. The connection part between the geomembrane and rigid structure should be added with GCL bedding,and the exhaust blind ditch should be set up under the geomembrane. The reasonableness of the geomembrane impermeable structure scheme should be evaluated by the design of seepage volume of the reservoir. The outer dam slope of the embankment is dry and the water level in the seepage collection corridor is normal after the trial impoundment the Xixia Reservoir which has been expanded and reconstructed. Although the daily seepage volume monitored near the water transmission tower culvert is 17～112 m~3,the comprehensive evaluation shows that the design of the geomembrane impermeable structure scheme of this reservoir is reasonable,and the geomembrane construction quality is generally good.更多还原