Observed performance of three adjacent 48 m depth concrete diaphragm wall panels in silty soils

Abstract

The performance of three adjacent 48 m depth concrete diaphragm wall panels in silty soils is measured throughout the complete process of the wall installation including trench excavation, trench concreting, and concrete hardening. The analysis of the field measurement data shows that the ground movement induced by the wall installation is a function of construction activities. The maximum lateral movement occurs during the trench excavation. The trench concreting reduces the lateral movement. Field measurement at the end of wall installation may not catch the value of the maximum lateral movement. The ground settlement continues to increase during the complete process of panel installation, but with a decreasing rate. Roughly 90% of the settlement occurs during the trench excavation. The ground movement is also closely related to the properties of subsurface strata. The weak superficial fill materials sustain high disturbance, which consequently results in relatively large ground movement. With current engineering means and methods and good construction workmanship, the ground movement can be well controlled. In the current project, the maximum lateral ground movement was controlled within 2.0 cm and the maximum settlement was controlled within 0.05% of trench depth.