大倾角煤层采后地下水系统状态及其修复方案

Status and remediation plan of groundwater system after mining in steeply dipping coal seam

运用地质学、采矿学和水文地质工程技术理论,通过对大倾角煤层采后围岩扰动非对称性的认识,研究分析其采后地下水系统呈现水平顺层、倾斜顺层、水平越层、垂向越层等多种水力联系形式,尤其以垂向水力联系方式,加剧了侵蚀基准面以上的地下水往侵蚀基准面以下的流失。借鉴保水采煤和注浆截堵的技术,首次提出对大倾角煤层采后地下水系统的修复技术方案。在非关键区域优先考虑自然修复,将各水平隔离带视为重点区域实行工程修复,实现地下水系统的小区修复促进大区域的恢复。特别是平硐水平,应首先进行工程修复,以尽快促进侵蚀基准面以上的地下水系统的恢复。在工程修复方面,主要采取注(灌)浆截堵法,实行上行修复或下行修复以及2种方式的结合,对煤层采空区冒落充填段、顶底板岩层破坏扰动段,逐层逐段注(灌)浆,加固改造后,沿水平隔离煤柱带形成水平隔(阻)水带,减少地下水系统的垂向水力联系。并对今后的研究和实践方向提出了建议。

Based on the theory of geology,mining science and hydrogeological engineering technology,through the understanding of the dissymmetry of surrounding rock disturbance after mining in steeply dipping coal seam,this paper studied and analyzed that the groundwater system after mining presented a variety of hydraulic connection forms,such as horizontal bedding,inclined bedding,horizontal cross layer,vertical cross layer and so on,especially the vertical hydraulic connection,which intensified the loss of groundwater above the erosion datum to the erosion datum below.Drawing on the techniques of water retaining coal mining and grouting interception,the technical scheme of repairing the groundwater system after mining in steeply dipping coal seam was put forward for the first time.Priority should be given to natural restoration in non critical areas,and the horizontal isolation zone should be regarded as the key area for engineering restoration,so as to realize the small area restoration of groundwater system and promote the restoration of large area.Especially for the horizontal level of the adit,engineering restoration should be carried out first,so as to promote the recovery of groundwater system above the erosion base level as soon as possible.In the aspect of engineering restoration,the method of injecting(pouring)interception was mainly adopted,the upward restoration or downward restoration was carried out,as well as the combination of the two ways,inject(pouring)slurry layer by layer and section by section to the caving and filling sections of the coal seam goaf,the damaged and disturbed sections of the roof and floor rock layers,after the reinforcement and reconstruction,the horizontal water separation(blocking)zone along the horizontal isolation coal pillar zone was formed,the vertical hydraulic connection of the groundwater system was reduced.Some suggestions for future research and practice were put forward.