深部开采构造型突水危险性数值模拟分析

Numerical simulation analysis of structural water inrush risk in deep mining

本文以三山岛金矿为工程背景,利用FLAC^(3D)数值软件建立矿井深部开采流-固耦合数值模型,采用房柱式交替向上充填采矿法,在模拟采动条件下,尤其是采场通过F_(3)断层时,矿体、充填体内渗流场以及塑性区的演化过程,对矿井不同开采时段、不同开采区域的突水危险性进行分析。试验结果表明:①距离断层较远时(-825 m-1盘区),随着回采活动的进行,盘区内的孔隙水压迅速降低,对相邻盘区和断层内的孔隙水压也有一定降低作用。②距离断层较近时(-825 m-2盘区),随着回采活动的进行,岩体内节理裂隙不断延伸扩展并与断层沟通,形成渗流通道,导致矿坑涌水量迅速升高,断层内孔隙水压下降。现场回采过程中,当工作面接近或通过断层带时,矿井发生突水危险性最高,应采取重点监测,并通过注浆等手段防止水害事故发生。③通过断层之后(-825 m-3盘区),受回采降压作用影响,盘区内孔隙水压整体较小,并逐渐向两侧采空区充填体扩散降低,随着埋深的增加,断层突水危险性迅速升高。

In this paper,taking Sanshandao Gold Mine as the engineering background,the FLAC^(3D) numerical software is used to establish the fluid solid coupling numerical model of deep mining,simulates the evolution process of seepage field and plastic zone in ore body and filling body under mining conditions,especially when the stope passes through F_(3) fault,and analyzes the risk of water inrush in different mining periods and areas.The test results show that it is far away from the fault(-825 m-1 panel),with the progress of mining activities,the pore water pressure in the panel decreases rapidly,and it also reduces the pore water pressure in adjacent panels and faults to a certain extent.When it is close to the fault(-825 m-2 panel),with the progress of mining activities,the joint fissures in the rock mass continue to extend and communicate with the fault to form a seepage channel,resulting in the rapid increase of pit water inflow and the decrease of pore water pressure in the fault.In the process of on-site mining,when the working face approaches or passes through the fault zone,and it is the time with the greatest risk of water inrush in the mine.Key monitoring should be carried out,and water damage accidents can be prevented by means of grouting.After passing through the fault(-825 m-3 panel),the pore water pressure in the panel is small as a whole,and gradually diffuses and decreases to the filling body of goaf on both sides due to the effect of mining pressure reduction.In addition,with the increase of buried depth,the risk of fault water inrush increases rapidly.