采场覆岩破断与应力演化的梁拱二元结构及岩层特性影响机制  

Influence mechanism of beam-arch binary structure and strata characteristics on fracture and stress evolution of overlying strata in stope

作　　者：娄金福 LOU Jinfu(Coal Mining Research Institute,China Coal Technology and Engineering Group Co Ltd,Beijing 100013,China;Coal Mining Branch,China Coal Research Institute,Beijing 100013,China;State Key Laboratory of Coal Mining and Clean Utilization,Beijing 100013,China)

机构地区：[1]中煤科工开采研究院有限公司,北京100013 [2]煤炭科学研究总院开采研究分院,北京100013 [3]煤炭资源高效开采与洁净利用国家重点实验室,北京100013

出　　处：《采矿与安全工程学报》2021年第4期678-686,共9页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51874175,51774185);中国煤炭科工集团人才与条件项目(2018RC001)。

摘　　要：长壁采煤方法在我国井工煤矿得到了广泛应用,其回采过程伴随着覆岩运移破断与采动应力演化的耦合作用过程。针对这一伴生性科学问题,以典型地层的采场覆岩为例,揭示了采动应力场宏观形态的演化特征及产生机理,阐释了厚硬岩层对于宏观应力场演化的影响机制。研究结果表明,覆岩破断表现为梁拱二元结构,即:上覆岩层破断后块体堆积形态外表似梁,而以裂隙带为代表的覆岩呈应力拱式传力机制,无论是破断前还是破断后,以关键层为代表的厚硬岩层都是采动应力场内重要的承载骨架。究其原因,一是岩层内部主应力迹线呈拱形分布特征;二是同步弯曲的岩层组内各岩层的弯矩、最大弯曲正应力均与岩层自身的厚度、刚度呈正比关系,故此关键层等厚硬岩层的受力明显高于厚度小、刚度低的邻近岩层,致使其破断前后形成拱形、反拱形等主体承载结构,对覆岩运移破断及采场矿压显现有显著影响。Longwall mining has been widely used in underground coalmines in China,and its mining process was accompanied by coupling process of overlying strata migration and fracture and mining stress evolution.In view of this companion scientific problem,with overlying strata of typical formation as an example,the evolution characteristics and generation mechanism of macroscopic shape of the mining stress field were revealed.The results have shown that overlying strata fracture presents beam-arch binary structure,i.e.,after overlying strata fracture,the accumulated blocks look like a beam,while overlying strata represented by fissure zone presents a stress arch transmission mechanism.Both before and after fracture,thick and hard strata represented by key strata are important bearing framework in mining stress field for the following two reasons:principal stress trace inside strata is in arched distribution;bending moment and maximum bending normal stress of each stratum in synchronous bending group are proportional to thickness and stiffness of stratum themselves.Therefore,stress of key stratum with equal thickness and hardness is significantly higher than that of adjacent strata with smaller thickness and lower stiffness,which results in formation of arch,reverse arch,and other main load-bearing structures before and after fracture,having significant impact on overlying strata migration and breaking and mining pressure in the stope.

关 键 词：长壁采煤法 采动应力 梁拱二元结构 主应力迹线 应力拱 关键层 

分 类 号：TD323[矿业工程—矿井建设]