Effects of fault zones on failure mechanism of tunnel, an experimental study

Abstract

This paper presents a large-scale experiment for studying the effects of fault zones on the failure process and failure pattern of tunnel. Firstly, appropriate synthetic materials representing fault zones and rock mass were developed. The mix of fine sand and grease was adopted to model the fault zones. Secondly, an experimental model was then performed to investigate the effects of fault zones on the progressive failure of tunnels. It was found that the presence of fault zones caused the asymmetry of convergent deformations and failure patterns. The fault zone itself failed initially and became a slip surface, which then led to the failure of surrounding rock masses and eventually caused the collapse of the tunnel. Failure mechanisms of tunnels with a fault zone obtained by model tests are helpful for the implementation of optimum support designing.