摘要
为揭示大倾角大采高采场覆岩变形破坏的时空演化特征及应力路径效应,以2130煤矿25221工作面为研究背景,采用3DEC数值模拟方法,在对覆岩变形破坏时空演化特征的综合厘定与分析的基础上,提出了大倾角采场上覆岩层在采动应力作用下的扰动分区,量化了采场沿工作面走向、倾向及不同层位覆岩采动应力路径的空间演化规律,揭示了采场空间不同区域覆岩采动应力与断裂失稳过程中的对应关系。研究结果表明:在大倾角大采高开采中,重力-倾角效应作用下矸石呈现非均匀充填特征,导致覆岩垮落形态及顶板承载拱在采场空间均呈现出典型的跨层迁移转化特性,包络面内中上部区域“倒三角临空面+倾斜砌体结构+高位梯阶岩层”形成空洞现象,“高位梯阶岩层”失稳易诱发“倾斜砌体结构”同时断裂,对支架形成较大的冲击动载荷。工作面煤层开采导致采场上覆岩层的三向采动应力大小、方向均发生了显著变化。沿工作面走向,覆岩最大主应力演化先增大再减小,最小主应力则先减小再反向增大,最大和最小主应力沿推进方向的垂直平面内向采空区旋转,上覆岩层的极限平衡状态界面沿工作面倾斜方向呈非对称展布。沿工作面倾向,煤柱侧上方岩层产生应力集中,工作面上方岩层卸荷,覆岩层位越低,其峰值应力越大,应力变化幅度越大。最大主应力主要沿水平方向发生偏转,最小主应力则由工作面推进方向逐渐向垂直方向偏转。由弱扰动区域至采空区中心,应力反向偏转位置由倾向中部逐渐向上部移动,应力路径的非对称偏转传递特征愈发明显。大倾角大采高采场采动应力时空演化规律及采动应力-位移-覆岩断裂结构的映射关系为揭示大倾角大采高采场围岩失稳致灾机理提供基础,并结合生产实际,提出了大倾角大采高综采工作面坚硬顶板冒垮压架防治措施。
In order to reveal the spatial and temporal evolution characteristics and stress path effect of overlying stra⁃ta deformation and failure in steeply dipping and large mining height stope,taking the 25221 working face of 2130 coal mine as the research background,the 3DEC numerical simulation method is used to determine and ana⁃lyze the spatial and temporal evolution characteristics of overlying strata deformation and failure.The disturbance parti⁃tion of overlying strata under the action of mining stress in steeply dipping stope is proposed,the spatial evolution law of mining stress path of overlying strata along the strike,inclination and different layers of working face is quantified,and the corresponding relationship between mining stress and fracture instability in different areas of stope space is re⁃vealed.The results show that in the mining of steeply dipping and large mining height,the gangue presents non⁃uni⁃form filling characteristics under the action of gravity⁃dip angle effect,which leads to the typical cross⁃layer migration and transformation characteristics of overburden caving form and roof bearing arch in the stope space,and the hollow phenomenon is formed in the middle and upper part of the envelope surface“inverted triangle free surface+in⁃clined masonry structure+high ladder rock layer”.The structural instability of the“high ladder rock layer”is easy to induce the simultaneous fracture of the“inclined masonry structure”and form a large impact dynamic load on the sup⁃port.Coal mining of working face results in significant changes in the magnitude and direction of three⁃dimension⁃al mining stress of overlying strata.Along the strike of the working face,the maximum principal stress evolution of the overlying strata increases first and then decreases,while the minimum principal stress decreases first and then increa⁃ses in the opposite direction.The maximum and minimum principal stresses rotate inward to the goaf along the vertical plane of the advancing direction,and the limit equilibrium state interface of the overlying strata is asymmetrically dis⁃tributed along the inclined direction of the working face.Along the tendency of working face,the stress concentration occurs in the rock stratum above the coal pillar side,and the rock stratum above the working face is unloaded.The lower the overburden position,the greater the peak stress and the greater the stress variation.The maximum principal stress is mainly deflected along the horizontal direction,and the minimum principal stress is gradually deflected from the working face advancing direction to the vertical direction.From the weak disturbance area to the center of goaf,the reverse deflection position of stress gradually moves from the middle to the upper part,and the asymmet⁃ric deflection transfer characteristics of stress path become more and more obvious.The temporal and spatial evolution law of mining stress and the mapping relationship of mining stress⁃displacement⁃overburden fracture structure in steep⁃ly dipping and large mining height stope provide the basis for revealing the mechanism of surrounding rock instability.Combined with the actual production,the prevention and control measures of hard roof collapse and support crushing in a fully mechanized mining face with steeply dipping and large mining height are put forward.
作者
解盘石
黄宝发
伍永平
陈建杰
刘文静
XIE Panshi;HUANG Baofa;WU Yongping;CHEN Jianjie;LIU Wenjing(Key Laboratory of Western Mine Exploitation and Hazard Prevention Ministry of Education,Xi’an University of Science and Technology,Xi’an 710054,China;School of Energy Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Xinjiang Coking Coal Group Corporation Lim-ited,Urumqi 830025,China;Shaanxi Coal and Chemical Technology Institute Co.,Ltd.,Xi’an 710065,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2023年第S02期424-436,共13页
Journal of China Coal Society
基金
国家自然科学基金面上资助项目(52174126)
山东省重大科技创新工程资助项目(2019JZZY020326)
陕西省自然科学基础研究计划-陕煤联合基金资助项目(2021JLM-10)。
关键词
大倾角煤层
大采高
覆岩变形破坏
采动应力变换
采动应力-位移-覆岩断裂结构映射关系
steeply dipping coal seam
large mining height
overlying strata deformation⁃failure
mining stress trans⁃formation
mapping relationship of mining stress⁃displacement⁃overburden fracture structure
作者简介
解盘石(1981-),男,陕西三原人,教授,博士。E-mail:xieps@xust.edu.cn;通讯作者:黄宝发(1998-),男,陕西安康人,博士研究生。E-mail:3251403264@qq.com。
