Optimization design of partition wall in deep excavations based on 3-D numerical simulation

As a technique for protecting adjacent buildings, partition wall has got an application to deep pit engineering. However the design of its parameters still lacks theoretical guidance. Based on a large-scale deep pit case, a 3-D finite element model is presented using the software ABAQUS. The behavior of soil is assumed to conform to modified Cam-clay model; and the actual construction sequence is simulated. Parameters relevant to the partition wall are analyzed in detail. The calculated and measured settlements of the adjacent building demonstrate the rationality of the optimization analysis of these parameters. It is shown that the ground surface displacements, the transverse angular distortions of the building and the maximum horizontal displacements of the retaining wall decrease with the increase of the partition wall depth. Nevertheless, the rate of the decrease of transverse angular distortions tends to be small if the partition wall depth is greater than a certain value. Thus there exists a reasonable depth for the partition wall. As the partition wall moves toward the adjacent building, the transverse and lengthways ground settlements, the differential settlements as well as the transverse angular distortions of the building decrease. Theoretically, the closer the partition wall is to the adjacent building, the better its effects are. The installation plane range of the partition wall also has significant influence on the adjacent buildings. Usually the range of the protected building can be the appropriate range of the partition wall. It is also shown that the stiffness of the partition wall does not affect the surface settlements and the angular distortions of adjacent building significantly, a medium-stiffness partition wall is sufficient to meet the engineering demands.