Early-age stress analysis of a concrete diaphragm wall through tensile creep modeling

Abstract

This paper reports a recent large-scale experimental investigation on early-age stress evolution in a deep underground concrete diaphragm wall. To evaluate the early-age stress induced by hydration temperature rise, autogeneous shrinkage and reinforcement restraint, both laboratory tests and in situ large-scale model wall test are performed. The laboratory tests include concrete adiabatic temperature rise, autogeneous shrinkage and restraint test. The in situ model wall simulates continuous and sliding design options for the external and inner layers with thermal and strain sensors installed in the inner layer. The restraint test results are interpreted via tensile creep modeling and an algorithm is conceived to calibrate the concrete tensile creep law. With the identified creep law, a thermomechanical analysis is performed on the model wall to calculate the concrete temperature and stress evolution at early age. The identified tensile creep law is furthermore validated by the numerical results and in situ measurements. Furthermore, the early-age stress analysis is performed on the full-scale diaphragm wall. Comments on the concrete tensile creep law and the diaphragm wall design option are given in the end.