Study On The Large Deformation Prediction Under High Geo Stress In Daliang Tunnel

In this thesis, several methods such as theory research, monitoring measurement, numerical simulation, investigation and analysis of surrounding rocks, etc. are adopted to study large deformation prediction of soft surrounding rocks under high geo stress, which is based on a project entitled "Study of control technique for great deformation tunnels in soft rock under high geo stress conditions", proposed by China Railway Co.VisualBasic6.0is involved in establishing a forecasting procedure for predicting deformation of Daliang tunnel, numerical simulation calculation is also conducted to evaluate its construction process, in which support parameters are optimized.The main research contents in this thesis are elaborated from the following aspects:(1)On the basis of research status at home and abroad, forecasting parameters and criteria are put forward in predicting large deformation. According to various characteristics of different prediction methods, large deformations could be forecasted in design stage and construction stage respectively.(2)A classification scheme of surrounding rocks suitable for Daliang tunnel is established, in which many geological factors such as rock properties, rock mass structure and groundwater information could complement each other, qualitative judgment and quantitative judgment could be combined mutually, evaluation methods could work collectively and related to each other.(3)Numerical Simulation Method is selected to analyze typical sections which tend to deform severely. Crown settlement and surrounding convergence values are imperative in calculations.(4)Based on the grey system theory, VisualBasic6.0is applied to program forecasting procedures, then monitoring deformation and displacement of surrounding rocks. Simultaneously, comparison between calculation value and measured value could demonstrate if it is practical.(5)Numerical Simulation Method is used to analyze whether it is more secure with the tunnel under reinforced support system during construction comparing to that under conventional support system, especially for large deformation sections, consequently, supporting parameters are optimized.