基于槽波理论的煤巷超前探测成像方法研究

It is necessary to prospect geological anomalies in coal seam for preventing water bursting and collapse accidents in roadway excavation. The traditional prospecting methods, such as direct current electric method, transient electromagnetic and ground penetrating radar, have such near detection distance and low resolution that could not meet the demand of ahead prospecting and affect the working progress of roadway excavation. The seismic channel waves are a strong energy signal and may propagate so long distance, therefore it is of theoretic value and great significance to study the ahead prospecting method using channel wave information in coal seams. The ahead prospecting using channel wave has two difficulties: (1) first, roadway type of channel wave is developing beside the Rayleigh and Love channel waves because of roadway existence, which results in difficult identification and separation of various channel waves; (2) second, channel wave’s dispersion take the trouble to location and migration imaging of geological bodies. To solve these problems, in this application the propagation characteristics will be investigated based on numerical simulation of elastic wave equation for identifying and separating various channel waves. Then, how to remove the frequency dispersion effect of various channel waves will be studied by using the waveform compression or wave shaping deconvolution for location and imaging the geological anomalies with Kirchhoff migration. At last, a group of theory and methods of ahead prospecting in coal seam will be developed through this research.

煤巷挖掘过程中需要对掌子面前方的地质异常进行超前探测，以防止突水、塌陷等事故的发生。煤巷中的传统超前探测方法，诸如直流电法、瞬变电磁和探地雷达等，探测距离近或分辨率低，远不能满足超前探测的要求，严重影响巷道挖掘安全性和施工进度。地震槽波能量强、传播距离远，因此研究利用反射槽波进行超前探测的方法具有理论意义和实用价值。利用反射槽波进行超前探测的主要难点，一是煤巷的存在，除了存在常见的瑞雷型和勒夫型槽波外，还发育巷道型槽波，造成槽波识别、分离的困难；二是槽波具有频散性，常规的偏移成像算法无法准确成像。针对上述问题，本申请将研究含巷道煤层中各种类型槽波的识别和分离方法；然后，研究如何消除槽波的频散特性，使反射槽波能够满足常规偏移算法的要求，并利用Kirchhoff积分偏移法对地质异常体进行成像，最终形成一套有效的煤巷槽波超前探测理论与方法。

本项研究利用槽波的传播距离远、能量强等特点，探索了地震偏移方法用于煤巷超前探测的可能性，取得了三项重要成果，分别是“二维煤巷超前探测克希霍夫深度偏移方法”，“三维煤巷超前探测克希霍夫深度极化偏移方法”和“三维煤巷超前探测逆时深度极化偏移方法”。这些成果可用于煤矿巷道和隧道的超前地质探测中，以预防地质灾害的发生。.第一项研究成果“煤巷二维槽波超前探测成像方法”，已经移交给北京中矿大地地球探测工程技术有限公司，2020年开始在数十个煤矿开展了应用工作，取得了良好成果和效益（项目费约1500万元），解决了煤矿煤巷掘进中的安全问题。