Geomechanical Model Testing of Surface Rupture and Bridge Damage Produced by Discontinuous Reverse Faults

Coplanar and stepped buried reverse faults were carried out to study the relationship between faults movement and surface rupture appearing in soil layer using geomechanical model test.Furthermore,the Gaoyuan Bridge damaged during Wenchuan Earthquake was taken as an example to study the effect of fault propagation on bridge foundation by changing the arrangement of the bridge to these two types of faults.Digital speckle correlation method and high speed camera were used to observe and analyze the process of the fault movement.We have studied the effect of fault dip angles and loading rates.The research results indicated that the failure process of discontinues reverse faults can be divided into four stages:elastic stage,fault coalescence stage,sliding stage and failure stage.The width of surface rupture zone,the uplifts of bedrock and sediment layer were statistics,which indicated the width of surface rupture zone and the uplift of the coplanar type were greater than the stepped one.The larger the fault dip angle,the wider the surface rupture zone was resulted.The uplift of bedrock was greater than the uplift of soil layer.The bridge perpendicular to the fault was damaged and no damage to the parallel one.