Research On Location Method Of Microseismic Events Outside Station

As an important dynamic,real-time and three-dimensional safety monitoring method,microseismic monitoring technology has been widely used in engineering applications such as mining,tunnel construction,and hydraulic fracturing.As the core technology of the microseismic monitoring system,focal location has always been the focus and hotspot of domestic and foreign scholars.At present,in linear engineering such as tunnel construction and hydraulic fracturing,microseismic sources are mostly outside the array of sensors(station),which further leads to a series of new challenges,such as inaccurate positioning of microseismic sources,low positioning efficiency and stability,and difficulty in accurately predicting rockburst risks.At the same time,accurate first arrival picking is a crucial part of achieving source location.Since accuracy has a great influence on the source location results,and the micro-seismic data has low signal-to-noise ratio,efficient and accurate first arrival picking is also the key to microseismic monitoring technology.Based on the above problems,this paper studies the first arrival picking method and the microseismic localization method outside the array of MS sensors:(1)The research on the microseismic monitoring network shows that the location of the microseismic source is affected by the layout of the network.Generally,the location error of the source outside the array of MS sensors is larger than that within the array.(2)Aiming at the problem that the picking accuracy of microseismic signals is not high under high-noise conditions,a joint picking method based on wavelet multi-scale analysis and AIC algorithm is proposed.The improved algorithm is validated by forward data and field measured data.The results show that the algorithm can be effectively applied to the first arrival of strong noise microseismic data,and the picking accuracy is obviously improved.The error is between 0.25~0.5ms.(3)In order to improve the efficiency and stability of the micro-seismic positioning process,based on the TDPS positioning method and the idea of double-difference method,an improved micro-source location method suitable for micro-seismic events outside the station is proposed.The forward model is established,and the improved algorithm is used to verify the accuracy of the positioning outside the station.The original TDPS method is used to compare the positioning effect and error.The results show that the positioning accuracy of the improved algorithm is significantly increased,and the error is reduced by 59.98%.It has stronger stability.(4)Taking the actual measured data of the blasting site of the Shuijiang Aluminum Mine as an example,the application of the two improved algorithms in the paper is verified.Finally,better microseismic monitoring results are obtained to verify the feasibility and reliability of the research results in this topic.