Abstract: The combination of cutoff wall and composite geomembrane is usually used as the imperious system recent years. The uncoordinated deformation between the cutoff wall and the fillings will cause the composite geomembrane cracks. The connecting form between cutoff wall and composite geomembrane is studied through geotechnical centrifuge tests. Four model tests considering the cutoff wall, wall mud, the backfilled materials and the connecting form are performed to investigate the variation of the strain of the composite membrane. When the geomembrane is laid horizontally on the top level of the cutoff wall, it is seriously strengthened at the connection near the cutoff wall, and the geomembrane is broken down when the differential settlement increases to a certain value. When the geomembrane is first laid vertically above the cutoff wall and then horizontally extended outward, the tensile strain of geomembrane is less at the connection. The longer the distance to the connection point, the less the strain. The existence of wall mud can effectively alleviate the local strain of the geomembrane.

Key words: cofferdam, centrifugal model test, composite geomembrane, strain, cutoff wall, mud