Perception Methods For Bad Geology Based On Shield Tunneling Parameters

The shield construction method has been widely used in tunnel construction due to its many advantages such as more applicable geology,less impact on the environment,and fast construction speed.In shield construction,it is a huge challenge to break through the complicated and changeable geology.For example,there are many bad geology in the south of China,such as upper-soft lower-hard ground,solitary rocks,which will affect the construction progress and even the construction safety.At the same time,due to the technical and cost,the geological exploration data can not give a more detailed geological conditions,so real-time sensing of the geology in front of the shield has become an urgent problem to be solved.In view of this situation,a study on the method of sensing the bad geology based on the tunneling parameters of the shield tunnel is conducted.The main research contents and results are as follows:1.Through the analysis of the theoretical calculation formulas,the influence of hard rock on the total thrust and the cutter head torque was found,and the bad geological conditions,such as sudden changed upper-soft lower-hard ground or solitary rocks,will have the most direct impact on thrust and torque.According to the statistical analysis and correlation analysis of the tunneling parameters in actual engineering,several groups of tunneling parameters with high correlation were found.2.According to the results of the theoretical and parameter analysis,several tunneling parameters such as cutter head torque,total thrust,soil pressure,and several shield machine parameters such as cutter head opening rate and excavation diameter were selected.From the perspective of single tunneling parameter and energy,the bad geological perception model was established,and the expressions of thrust perception coefficient,torque perception coefficient and power perception coefficient were defined.On this basis,the data collection matrix and the bad geological perception matrix were established,and an early warning mechanism for bad geological perception was formulated.According to the difficulty of the geological excavation,nine judgment levels were set from low to high.3.Combined with the engineering data of Zhuhai Hengqin tunnel,Shijiazhuang Metro and Fuzhou metro,the bad geological perception model was verified.The results show that the perception effect is good,which has a certain reference value for shield construction.4.Based on the python language,the development platform of python3.6 + Py Qt5 + Py Charm + Microsoft SQL Server 2 008R2 was used to build bad geological sensing software,which realizes the judgment of bad geological excavation difficulty,real-time monitoring of tunneling parameters,data analysis of various parameters,Historical data query and export functions.