Deformation behavior and damage analysis of underground high-voltage cable duct bank encased by concrete

Abstract

Due to the shallow burial depth, the concrete duct bank for underground cables frequently encountered differential settlement, tilt and other damage like cracking when construction activity was carried out in the vicinity. This paper briefly presents an experimental study of concrete duct bank with a 1/4 part of real structure under a monotonic static loading, which was put into a soil box in the laboratory. And then numerical simulations were performed for the 1/4 part of real structure and a real-scale concrete duct bank respectively, to investigate the deformation and damage pattern of concrete structure and the wrapped inside conduits. Both the test and numerical results indicated that the failure of concrete duct bank presented a distinct brittle pattern. The mechanical properties of underlying soil play a more dominant role in the bearing capacity, mid-span vertical displacement and mid-span deflection of concrete duct bank. It is proposed that the vertical displacement of concrete duct bank can be set as the monitoring item to reveal its safety state, and the minimum curvature radius of longitudinal deformation profile obtained from vertical settlement at different locations can be computed and be taken as the control index.