抄録
Six centrifuge tests were conducted to study the possible failure mechanisms for open excavations in soft clay with DMM self-supported walls, and the pre-failure soil and wall behavior, as well as the effect of some parameters on the wall external stability. In the tests, in-flight excavation was conducted until failure. The DMM wall was modeled by a wall made from aluminum and acrylic plates, which were instrumented with pressure cells to measure the active and passive earth pressures, and the base contact pressure of the wall during excavation. Upper bound analysis was conducted to verify the efficiency of the currently used design method, and to identify the main parameters which affect the external wall stability. It was found that the failure of the excavations with DMM self-supported walls floating in the clay, took place suddenly without marked pre-failure soil and wall movements. The main parameters which affect the wall stability are the wall dimensions, the soil strength profile, the adhesion between the wall surfaces and the surrounding clay, the strength anisotropy, and the surcharge on the clay surface. The soil strength profile and the adhesion between the wall surfaces and the clay were found to be the most important parameters.
