西霞院反调节水库土石坝膜防渗工艺

Geomembrane seepage control techniques of Xixiayuan earth-rock dam

黄河西霞院反调节水库土石坝采用土工膜前置防渗,通过设置土工膜并根据接触作用的三维数值计算得出膜周边锚固部位的相对位移,设计该部位膜吸收位移的铺设方式。在环境温度ti为2~33℃范围内每间隔5℃设置3个焊接温度tw,通过对应焊接试样的拉伸、剥离试验,获得ti^tw关系曲线,以指导施工焊接;通过焊接试样附着水分、尘埃、纤维的焊接试验,证明复杂环境下保持焊接部位清洁对保证焊接质量的重要性;通过锚固试件的渗透试验,证明锚固工艺的可靠性;通过对复合土工膜复合工艺的改造,满足坝轴线弯曲段复合膜的拼接、铺设平顺。经蓄水一年后现场检查,膜拼接、锚固部位运行可靠。

Prepesifive geomembrane seepage control is used in the earth-rock dam of the Xixiayuan Counter Reservoir along the Yellow River. The relative displacement in the position of the anchor point was calculated from the geomembrane arrangement and a three-dimensional numerical calculation of contact interactions, and the geomembrane paving pattern in this position was designed. In an environmental temperature （ti） range from 5 to 35℃, three weld temperatures （tw） were achieved every other 5℃. The ti-tw,curve was obtained through the tensile test and pod test of the welding sample, which guides welding construction. Weld experiments with welding samples containing water, dust or fiber show the importance to welding quality of keeping the welded area clean. The leliability of anchoring technology was proven through the permeability exporiment of the anchor sample. The splicing and laying of composite geomembrane in the curved interval along the dam axis can meet the requirements of the process modification of composite geomembrane. After one year＇s operation for water storage, site inspection shows that the weld seals and anchor locations are reliable.