Stability of excavations in soft clay with floating self supported DMM wall

Centrifuge model tests were carried out in order to investigate the failure mechanism of excavations in soft clay using self supported walls made by deep mixing method. The wall was modeled using Aluminum and Acrylic plates and the external stability of the DMM wall was mainly studied. In-flight excavations were conducted until failure. The wall and ground deformations, pressures acting on the wall and pore water pressure in the soil were measured during excavations. It was found that adhesion mobilized on the wall surface had a significant effect on the stability. Sliding type failures were observed in the tests with wall height/width ratio less than 2 and the failure suddenly took place without showing marked pre-failure deformation.