改进复合土工膜的铺设和联接型式,增强其对堰体变形的适应性,是将复合土工膜作为防渗体系的土石围堰设计的关键。开展复合土工膜围堰的离心模型试验,得到蓄水期土工膜应变分布规律;采用ABAQUS软件提供的薄膜单元M3D4模拟了离心模型试验,获得不同铺设及联接型式复合土工膜应力变形空间分布特性,并将数值模拟结果与离心模型试验结果进行比较。结果表明:S型铺设的土工膜受力比直线型铺设的土工膜受力合理;S型铺设锚固联接土工膜起到了加筋作用,降低了围堰的沉降变形;土工膜在锚固联接处局部有应变集中部位,柔性联接介于锚固联接与无联接之间,变形协调性更强;采用的土工膜模拟算法能较好地反映离心模型试验的成果。

To improve the laying and connection type of composite geomembrane and to enhance its adaptability to cofferdam deformation is the key to the design of earth-rock cofferdam with composite geomembrane as seepage control system. Centrifugal model test was carried out to obtain the strain distribution of geomembrane in water-storage period; numerical simulation of the centrifugal model test was also conducted by using the membrane unit M3D4 provided by ABAQUS to acquire the spatial distribution characteristics of stress and deformation of composite geomembrane with different laying and connection patterns. The numerical simulation results were compared with the centrifugal model test results, and the comparison illustrated that the stress of geomembrane laid in an S-shape was more reasonable than that in linear type as the S-shape plays a reinforcing role and reduces the settlement of cofferdam. Strain concentrated in the connection part of geomembrane and the restraint effect of flexible connection is between that of anchorage connection and unconstrained connection, implying stronger deformation compatibility. The results of centrifugal model test can be well reflected by the geomembrane simulation algorithm.