基于3种计算方法的采空区顶板稳定性综合分析  

Comprehensive analysis of roof stability in goaf based on three calculation methods

作　　者：朱志岗 侯克鹏[1,2] 孙华芬 牛向东[1] 褚占杰 李耀楠[1] ZHU Zhigang;HOU Kepeng;SUN Huafen;NIU Xiangdong;CHU Zhanjie;LI Yaonan(School of Land and Resources Engineering,Kunming University of Science and Technology,Kunming Yunnan 650093,China;Yunnan Key Laboratory of Sino-German Blue Mining and Utilization of Special Underground Space,Kunming Yunnan 650093,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]云南省中-德蓝色矿山与特殊地下空间开发利用重点实验室,云南昆明650093

出　　处：《化工矿物与加工》2020年第5期11-14,17,共5页Industrial Minerals & Processing

摘　　要：采空区的顶板稳定是地采作业安全的前提,以某铝矿为研究对象,在现场具有代表性的部位取样,通过室内岩石力学试验并采用Hoek-Brown强度准则折算出采场矿岩力学参数,分别运用简支梁理论、荷载传递交线法和厚跨比法计算分析了该矿山一期3#采场的稳定性。采用简支梁理论并结合数值模拟分析可知,跨度最小为21.6m的岩梁下表面的拉应力为4.79MPa,大于顶板的抗拉强度4.44MPa;岩梁极限跨度为20.82m,小于岩梁最小段跨度21.6 m;最小跨度岩梁中部下沉量达到2.3m,可判定此岩梁将发生破坏。采用荷载传递法分析得知,当β取35°时,采空区安全跨度为2.8m;β取30°时,安全跨度为2.3m,3#采场内各矿柱之间的距离远大于安全跨度,即采空区会发生顶板失稳。使用厚跨比法分析得知,当安全系数为1.0时,保持直接顶稳定的极限跨度为4m;当安全系数取1.5时,保持直接顶稳定的跨度为2.66m;3#采场内各矿柱的间距远大于极限跨度。综合分析可知,该矿山采空区的顶板稳定性差,需要增加矿柱数量,并对现有矿柱进行加固,或用混凝土矿柱置换。The stability of roof is the premise of the safety of mining operations.Taking an aluminum mine as the research object,samples taken from representative parts in the site,mining rock mechanical parameters were converted by indoor rock mechanics test and Hoek-Brown strength criterion,and the stability of No.3stope in Phase I project of the mine was calculated and analyzed by using simple beam theory,load transfer intersection method and thick-cross ratio method respectively.Based on the simple supported beam theory and numerical simulation analysis,the tensile stress on the lower surface of the rock beam with the minimum span of 21.6mis 4.79MPa,which is greater than the tensile strength of the roof 4.44MPa.The ultimate span of the rock beam is 20.82m,which is smaller than the minimum span of rock beam of 21.6m.The subsidence in the middle part of rock beam reaches 2.3m,so it can be concluded that rock beam will be damaged.The analysis by load transfer method shows that with 35°taken forβ,the safety span of goaf is 2.8mand with 30°taken forβ,the safety span is 2.3m.The distance between each pillar in No.3stope is far greater than the safety span,that is,roof instability will occur in the goaf.Based on the thick-cross ratio analysis,when the safety coefficient is 1.0,the limit span to maintain the direct roof stability is 4m.When the safety coefficient is 1.5,the span of maintaining the direct roof stability is 2.66m.The spacing of each pillar in No.3stope is much larger than the limit span.According to the comprehensive analysis,the stability of the roof in the underground goaf of the mine is poor,so it is necessary to increase the number of pillar,reinforce the existing pillar or replace it with concrete pillar.

关 键 词：采空区 顶板稳定性 简支梁理论 荷载传递交线法 厚跨比法 极限跨度 抗拉强度 

分 类 号：TD325[矿业工程—矿井建设]