Prediction On The Ground Surface Settlements Due To Metro Tunnels Construction Using Mining Method

With the continuous economic and social development and the gradual promotion of Urbanization process, China's major cities have undertaken the construction of urban rail transit. Urban rail transit represented by metro has played a very important role in promoting our national urbanization process and accelerating our country's economic and social development. However, as the high-risk of metro construction, historical data show that in the process of metro construction, various security incidents often happen. In the process of metro construction, ground surface settlement due to the metro construction is a key factor which influences the metro construction safety. It is not only related to the subway tunnel own security, but also a potential security threat to the surface structures and buildings along the subway line. So Paying a close attention to the surface settlement changes in the subway construction process, analyzing and predicting the ground surface settlement scientifically and reasonably will provide certain reference for the security of the subway construction and also provide necessary safety guarantee for structures and buildings along the subway line.In this paper, on the basis of consulting related documental materials and analyzing the actual engineering data, firstly summarizes the surface settlement mechanism caused by parallel twin tunnels construction and introduces the rules of ground surface settlement caused by parallel twin tunnels. Then, taking 25th section,1 stage project of Wuhan metro line 2 as an example, influence factors of surface subsidence caused by the parallel double tunnel construction were discussed and factor analysis are made. Finally, the article still takes 25th section,1 stage project of Wuhan metro line 2 as an example, by screening the monitoring cross-section and analyzing the cross-section data, based on the Peck formula and making a small correction on the small spacing superposition method, ground surface settlement of some sections are predicted.