Application Of Advanced Geological Prediction Method In Pingyang Tunnel

With the rapid development of China’s infrastructure construction,the country’s investment in transportation infrastructure in western mountain areas is increasing,and there will be more and more high-risk tunnels built in mountainous and karst areas with complex terrain and geological conditions.Affected by topographical geological conditions,geological survey technology,etc.,it is often difficult to fully grasp the engineering geological conditions in the region in the early stage of tunnel construction;especially in karst areas,faulty,karst,fractured zones and other unfavorable geological bodies are found throughout the region.Geological problems such as mud and rock bursts frequently occur in tunnels,which seriously threaten the safety of construction.In order to prevent geological disasters and ensure the safety of tunnel construction,advance geological forecasting and water inflow forecasting must be carried out.Based on the analysis and comparison of the current advanced geological forecasting methods of tunnel engineering,this paper summarizes the detection and acquisition steps and data processing procedures of seismic wave reflection method,full-space transient electromagnetic method,and geological radar method based on the actual conditions of Zhengwan high-speed railway Pingyang tunnel engineering.The problems that need to be paid attention to by different methods in actual detection are obtained.In the detection of bad geological bodies,the seismic wave reflection method(TGP,TST),full space transient electromagnetic method,geological radar method,advanced drilling method and other methods were used to successfully predict the bad geological bodies in front of the 3rd section of the Pingyang Tunnel.It effectively makes up for the shortcomings that the seismic wave reflection method cannot distinguish when encountering water-bearing geological bodies,and provides a scientific basis for the drainage scheme design and construction safety during tunnel construction.Finally,based on the hydrogeological survey report and field survey data,taking into account various factors such as geological structure,lithology,hydrometeorology,and tunnel location,the rainfall infiltration method,groundwater runoff modulus method,and groundwater dynamics method(Palestinian Deman formula,empirical formula for railway survey specifications)Prediction of normal and maximum water inflow during the construction period of the Pingyang Tunnel entrance.The normal water inflow calculated using the groundwater runoff method is compared with the maximum water inflow calculated using the Goodman formula.accurate.A differential autoregressive moving average model is established to make short-term predictions of water influx during the construction period of the Pingyang Tunnel entrance.The prediction results have greatly improved the prediction accuracy compared to other methods.It can be used as a reference and basis for formulating tunnel construction operations and drainageplans in the short term.Provide guarantee for project construction safety.