Prototype Model Tests of Ground Fissures under Dynamic Earthquake Effects in Xi'an, China

The Xi'an city metro system is located within an active geological area containing several ground fissure sites. This potential geological hazard can cause serious threats to construction of the new metro system. In this research study, prototype model tests were conducted to investigate the effects of the ground fissures on the metro system under earthquake forces. The prototype model box was loaded with several seismic forces of different characteristics and the changes in the ground fissures were surveyed. Test results showed that 1) The existing ground fissures opened wider under the applied seismic forces and new fissures appeared close to the existing cracks, 2) The seismic forces caused larger soil settlements within the vicinity of the ground fissures and the long duration earthquake forces resulted in larger soil settlements, 3) The laboratory prototype model tests resulted in very useful information in terms of the behavior of the ground fissures and their interactions with the metro system under the simulated seismic forces.