The exit portion of Gaoyangzai tunnel on Yiwan railway is located in fractured accumulative ground. It is of great difficulty to build largespanned doubletrack railway tunnels under such difficult geological conditions. Monitoring and measurement provide basis and safety guarantees for the rapid construction of the tunnel. The article presents the execution plan of the monitoring and measurement, analyses the monitoring results and expatiates on the feasibility of building largespanned doubletrack tunnel in fractured accumulative ground.