Abstract: Influenced by the lateral continuity effect of retaining wall’s cement soil, SMW (soil mixing wall) construction method displays significant spatial deformation characteristics of retaining wall. It is difficult to quantify the spatial deformation effect of retaining walls and the bearing capacity of cement soil, the function of spatial deformation effect and contribution of cement soil to retaining walls are not taken into account during the design of SMW construction method at present. By analyzing the deformation and stress of retaining wall of cantilever type SMW construction method, the strain energy of spatial deformation of retaining wall can be obtained. Ratio of spatial deformation effect and bearing ratio of cement soil of SMW construction method are defined according to the relationship between strain energy and resistance. Meanwhile, the analytic solution of displacement of the top of the wall is derived with a consideration of the spatial deformation effect of retaining wall based on the principle of minimum potential energy. The analytic solution is compared with the displacement calculated by elastic subgrade, the monitored displacement. In-depth discussion of factors influencing the spatial deformation effect ratio and the bearing ratio of cement soil is completed with a reference to the results of the model test. The results show that the analytic solution considering the spatial deformation effect is closer to the monitored values than the elastic subgrade method. The ratio of height to length of retaining wall, the elastic modulus of cement soil and the wall thickness in SMW construction method have a significant influence on the spatial deformation effect ratio and the bearing ratio of cement soil.

Key words: deep excavation, SMW (soil mixing wall) construction method, spatial deformation effect, bearing ratio, principle of minimum potential energy