煤矿"Y"型断层分支底板断裂力学判据及模拟研究

Fracture mechanical criteria and simulation of floors with Y-shaped branches of major faults in coal mines

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中文摘要：[目的]断层分支作为主断层的一部分普遍存在,不易引起人们重视,但断层分支是引起突水的主要因素之一.[方法]以安徽刘庄煤矿为工程地质背景,在考虑Mohr-Coulomb准则岩体压剪断裂判据基础上,建立断层分支渗流与应力双重影响下的断裂力学灾变模型,分析得出断层分支发生劈裂破坏时的临界水压及断层分支到底板破碎区最小安全距离,研究断层倾角、最小主应力、主断层长度和渗透水压对临界水压及最小安全距离的影响规律和主控影响因素,并模拟分析断层分支在采动影响下塑性区及渗流场的演化特征,开展现场压水试验的验证工作.[结果和结论]结果表明:(1)断层分支倾角越大越易发生突水;最小主应力越大,断层分支裂隙越不容易发生扩展;(2)当主断层倾角为 60°且断层分支与主断层夹角为 60°时,模拟分析结果显示在工作面推进至断层分支正上方位置时,断层导升通道整体活化贯通;当工作面推过断层分支正上方 10 m后,断层分支尖端裂隙与工作面底板破坏带贯通并引起底板突水;(3)通过现场压水试验验证了理论计算的正确性,证实断层分支会造成底板裂隙提前与断层相互贯通,引起工作面出水.研究结果可为煤矿采场底板含此类断层分支时的防水煤柱留设提供一定参考.

外文摘要：[Objective]Despite wide distribution,the branches of major faults(also referred to as the fault branches)tend to be overlooked.However,they represent one of the primary causes of water inrush.[Methods]Under the engineering geological background of the Liuzhuang coal mine in Anhui Province,this study established a fracture mechanical dis-aster model for fault branches under the impacts of both seepage and stress based on the criteria for compression-shear fracture of rock masses considering the Mohr-Coulomb criterion.Using this model,this study obtained the critical water pressure and the minimum safe distance between the fault branch and the floor's fractured zone in the case of fault branch splitting.It investigated the influence patterns of factors including the fault dip angle,minimum principal stress,length of a major fault,and seepage water pressure on critical water pressure and the minimum safe distance,determin-ing the dominant influencing factors.Furthermore,this study simulated the evolutionary characteristics of the plastic zones and seepage fields of the fault branches under the mining effects and verified the results using in-situ water pres-sure tests.[Results and Conclusions]Key findings are as follows:(1)A higher dip angles of the fault branches corres-ponded to a higher susceptibility to water inrushes,while a higher minimum principal stress suggested a lower probabil-ity of the fissure propagation of the fault branches.(2)In the case where the dip angle of the major fault and the angles between the fault branches and the major fault were both 60°,fault channels were entirely activated and connected when the mining face advanced directly above the fault branch,as indicated by the simulation results.After the mining face advanced 10 m away from the fault branches,fissures at the tip of the fault branches were connected to the fractured zone of the mining face's floor,resulting in water inrushes from the floor.(3)The in-situ water pressure tests verified the correctness of theoretical calculations,proving that fault branches can cause early interconnection between fissures on the floor and faults,leading to water outflow from the mining face.Overall,the findings of this study provide a refer-ence for setting up waterproof coal pillars in coal mines with Y-shaped fault branches on stope floors.

外文关键词：

water inrush from floorY-shaped fault branchfracture mechanical modelfault-induced water inrushnu-merical simulationin-situ test

作者：

李昂、孙靖昕、张文忠、张壮、杨宇轩、王伟东、吕伟、范六一

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作者单位：

西安科技大学建筑与土木工程学院,陕西西安 710054

陕西省煤矿水害防治技术重点实验室,陕西西安 710077

中煤科工西安研究院(集团)有限公司,陕西西安 710077

陕西建工第三建设集团有限公司,陕西西安 710054

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关键词：

底板突水 "Y"型断层分支断裂力学模型断层突水数值模拟现场试验

基金：

陕西省煤矿水害防治技术重点实验室开放基金项目陕西省自然科学基础研究计划重点项目国家自然科学基金面上项目

项目编号：

2020SKZD022020JZ-5251874229

出版年：

2024

DOI：

10.12363/issn.1001-1986.23.11.0776

煤田地质与勘探

中煤科工集团西安研究院

煤田地质与勘探

CSTPCD北大核心

影响因子：1.079

ISSN：1001-1986

年,卷(期)：2024.52(9)

参考文献量13