Seismic Response Analysis of Shallow Utility Tunnel in Liquefiable Soils

Abstract

A utility tunnel is a public underground structure that holds wires, conduits, pipes of power, gas, water supply and communication utility system and provides also enough space for maintenance. Construction of the utility tunnel represents the future orientation of development for underground infrastructure system in both cities and small towns because of it's many advantages as improving the project reliability, lessening maintenance cost and improving the environment. At present, many studies have focused on the affects of earthquake loading on the forces and displacements of underground structures, while the seismic response analysis of underground structure in liquefiable soil, especially to shallow utility tunnel is still lacking. The FLAC3D software has been used to simulate the pore pressure changes and utility tunnel internal forces characteristics during earthquakes that lead to soil liquefaction. The effects of soil features such as friction angle and dilatancy angle to the liquefaction are studied. The results show the increasing friction angle and dilatancy angle can be effective lessen the liquefaction and reduce liquefaction-induced uplifting of the utility tunnel. Some useful conclusions are obtained to understand the characteristics of shallow utility tunnel in liquefied soil through the analysis, which can be for design reference.