Research On Continuous Advance Detection And Imaging Methods Of Roadheader With Excavation Based On Electrical Method

Intelligent roadheader is the main development direction of coal mine roadway excavation,which is of great significance for comprehensively improving the level of coal mine roadway excavation equipment and technology,and ensuring safe,green,and efficient coal mine roadway excavation.As an important technology in intelligent tunneling,advanced detection of coal mine roadway plays an important role in improving roadway tunneling speed and ensuring tunneling safety.In view of this,this thesis proposes a continuous advance detection and imaging methods of roadheader with excavation based on electrical method,providing a feasible idea for achieving parallel operations of roadway excavation and advance detection.The main research work is as follows:(1)Propose a continuous advance detection scheme while excavating,using the cutting head of the roadheader as the field source for accompanying excavation,and integrating geophysical exploration methods with the main body of the roadheader;Explain the basic theory of direct current method,analyze the boundary conditions of stable current field,and theoretically analyze the evolution law of apparent resistivity when there are different types of abnormal bodies in front of the excavation face;The theoretical model of advance detection with excavation is constructed and the variation law of the potential at the measuring point is obtained.Compared with the results of finite element calculation,the accuracy and feasibility of the numerical calculation method of the potential at the measuring point are verified.(2)Through numerical simulation and analysis of the cutting head field source,the diversion rules of the field source along with the excavation are determined;Then,using normal geological bodies as a reference,a comparative study is conducted on the evolution law of apparent resistivity of two types of abnormal bodies,low resistivity and high resistivity,during the process of tunneling.The closer the field source is to the low resistivity water-bearing zone,the average decrease in apparent resistivity increased from 5.40% to 29.80%.The closer it is to the high resistance fault,the average increase in apparent resistivity increased from 7.12% to 35.53%.Therefore,the apparent resistivity can be used as the basic parameter to distinguish whether there is a low resistance water-bearing zone or a high resistance fault in front of the excavation face.(3)A method for identifying and imaging abnormal bodies through continuous advance detection during excavation has been proposed,which solves the problem of poor accuracy in single imaging of fixed field source advance detection.Firstly,a theoretical model for identifying and imaging anomalous bodies through continuous advance detection during excavation was constructed;Then,research is conducted on methods to improve the accuracy of abnormal body identification imaging;Finally,analyze the imaging effects of different types and shapes of abnormal bodies in front of the source during excavation.The results show that the continuous imaging accuracy of the field source during excavation is superior to the single point fixed field source imaging method,and the higher the excavation mileage,the faster the potential acquisition frequency,and the number of potential measurement points,the higher the imaging accuracy.The logarithmic conductivity mean square error of imaging for high resistance anomalous bodies is higher than that for low resistance anomalous bodies,and the imaging range for low resistance triangular anomalous bodies in front of the excavation field source is slightly larger than the true range.(4)Conducting a water tank experiment to simulate continuous advance detection during excavation in a homogeneous and isotropic medium,and simulating the continuous movement of the field source during the excavation process.The potential difference can also be continuously measured at the rear measuring point,which is significantly improved compared to the traditional method of static measurement using a single point power source as the field source.Conducting mud tank experiments to simulate the cutting head model of a tunneling machine for continuous advanced detection during actual excavation.Taking normal geological bodies as a reference,the evolution law of apparent resistivity of two different types of abnormal bodies,low resistance and high resistance,as well as the identification and imaging results of abnormal bodies during the excavation process were compared and studied.The closer the on-site source is to the low resistance anomalous body,the decrease in the average apparent resistivity increases from 6.33% to 21.97%.The closer the source is to the high resistance anomalous body,the increase in the average apparent resistivity increases from 2.42% to 42.87%.Moreover,the identification effect for anomalous bodies of continuous advanced detection with excavation is better than that of single point power imaging.There are 53 figures,8 tables,and 101 references in this thesis.