Parameters affecting the lateral movements of compound deep cement mixing walls by numerical simulations and parametric analyses

Abstract

A compound deep cement mixing retaining wall system is a combination of deep cement mixing (DCM) columns and precast reinforced concrete walls. This type of retaining wall was used in a deep excavation for a reservoir construction project in a soft clay area in Thailand. During construction, an inclinometer casing was installed to monitor the lateral movement profiles of this retaining wall system until construction had been completed. Studies on the parameters that affect the lateral movements of retaining walls of this type are limited because of the complex geometry involved. In this paper, a three-dimensional numerical model is first calibrated using an instrumented case history. Then, an analysis of the results for this case history is presented to characterize the wall behavior in terms of the ground settlement induced by wall deflection during excavation and in terms of lateral wall movement. Finally, a parametric study is performed. The results provide information on the influence exerted on the lateral wall movement by the following factors: the elastic modulus of the DCM columns, the embedded length of the DCM columns, the size of the DCM columns, the thickness of the precast wall, the thickness of the soft clay layer and the berm size. The influences of these factors are compared and rated in terms of their degree of importance.