Cantilever double soldier-pile walls are used in vertical excavations to minimize wall deformation. A model is proposed consisting of an equivalent single soldier-pile wall with twice the bending stiffness of a single soldier-pile wall, twice the area of the pile shaft in contact with the soil below the excavation level, and the maximum capable mobilized moment at ground level, which can be used to evaluate the stability of double soldier-pile walls. A series of centrifuge model tests at an acceleration of 30 g was conducted to study the performance of cantilever single and double soldier-pile walls in sand under various test conditions. The test results show that the use of a double soldier pile can effectively improve the performance of retaining walls. The proposed stability analysis also provides satisfactory predictions of the factors of safety for double soldier-pile walls at various excavation depths and with various pile arrangements, verified by the results obtained in the centrifuge model tests. The use of F(s) = 2.0 in the proposed stability analysis was found to be appropriate engineering practice for ensuring that the temporary cantilever double soldier-pile walls are stable and that the ratio delta(hm)/H does not exceed 1%.
