On Study Of The Deformation Characteristics And Stability Of The Railway Tunnel Surrounding Rock

China is a mountainous country. With the development of the economy, it is necessary for people to extend the underground space. In recent years, with the fast pace of the railway constructions, the research of the stability of the railway tunnel surrounding rock has caused a lot of attentions and has become one of the demanding tasks. But the existing theories and methods of stability are not mostly exactly appropriate the railway tunnel and there is no unified criterion to classify the tunnelsurrounding rock. It has far-reaching significance both for theory and practice to have a profound study of the railway tunnel deformation failure characteristics.The paper bases on the practice of Hai Ying tunnel engineering. With a comprehensive study of the geological environmental factors of working area, it begins with the rules of the surrounding rock deformation, along with the abundant monitoring and measuring information, analyzing the relationship among the surrounding rock deformation, time and excavated surface, finding an effective method to determine the stability of the surrounding rock during the construction process.It will identify and analyze the geological environmental background of HaiYing tunnel from DaLi to Li Jiang railway in Yun Nan province.According to the standard, it will determine and arrange the monitoring measurements of Hai Ying tunnel and make a numerical and statistical analysis. By means of theoretical calculation and numerical simulation, the paper will calculate and further amend the approximate formula relating surrounding rock's displacement according to the standard and the monitoring measurements.Based on the data of the monitoring measurements, the paper will make a regression curve. By using the first derivative and second derivative it will preliminarily judge the stability of the surrounding rock and determine the best time and deadline of secondary lining facilities.The analysis of deformation rate is a key to determine the stability of surrounding rock. Excluding the human factors to cause the rock deformation, the high speed of rock deformation can cause the instability of the surrounding rock.This method can be successfully used in Hai Ying tunnel as well as adjacent Pine Park tunnel, Tashan tunnel, the first and second tunnel in Tacun. With the safe constructions and high-speeding progress, the method saves the costs and has achieved an effective goal for research.