摘要
柱旁充填中煤柱与充填体之间的界面为煤充结构体的薄弱环节,对煤充结构体的劈裂特性具有重要影响。本文开展了不同界面角度情形下煤充结构体试样破坏的巴西劈裂试验,分析了煤充结构体试样的劈裂特性、破坏模式与受力状态,并揭示了其劈裂破坏机理。结果表明:煤充结构体可简化为由煤体元件和充填体元件共同组成的复合承载体,其劈裂力学特性与界面角度密切相关。煤充结构体试样整体抗拉强度随界面角度增加呈先增大后减小的变化趋势,表现出明显的各向异性。煤充结构体试样的破坏模式表现为:类型Ⅰ:裂纹主要沿煤充结构体试样界面扩展;类型Ⅱ:裂纹主要沿煤充结构体试样加载方向扩展;类型Ⅲ:裂纹沿煤充结构体试样界面方向和加载方向扩展。煤充结构体劈裂破坏机理体现在:界面上所受载荷达到界面抗压、抗拉或抗剪强度,使试样内部产生沿界面贯通的裂纹,发生Ⅰ类破坏。煤体元件所受载荷先达到其抗拉强度,最早产生拉伸裂纹;随着载荷持续增大,充填体元件所受载荷也达到自身抗拉强度,最终沿加载方向在试样内产生贯通型拉伸裂纹,发生Ⅱ类破坏。煤体元件所受载荷先达到其抗拉强度,产生拉伸裂纹;随着载荷不断增大,先后或同时达到界面强度和充填体元件抗拉强度,使试样内形成由拉伸裂纹和界面裂纹共同组成的贯通型裂纹,发生Ⅲ类破坏。本研究可为柱旁充填中煤充结构体劈裂失稳防控提供理论依据。
The interface between the coal pillar and backfilling body is the weak area in the coal-back filling structure and had an important influence on the splitting characteristics of coal-backfilling structure.The Brazilian splitting experiments of coal-backfilling structure samples under different interface angles were carried out in this study.The splitting characteristics,failure mode and stress state of coal-backfilling structure samples were analyzed and the splitting mechanism was revealed.The results showed that:The coal-backfilling structure could be simplified as a composite bearing body composed of coal body elements and backfilling body elements.Its splitting mechanical properties were closely related to the interface angle.With the growth of interface angle,the overall tensile strength of coal-backfilling structure sample increased firstly and then decreased.Specimens exhibited significant anisotropy.The failure mode of coal-backfilling structure with different interface angles could be expressed as:TypeⅠ-the cracks mainly extended along the interface of coal-backfilling structure sample.TypeⅡ-the cracks mainly propagated along the loading direction of coal-backfilling structure sample.TypeⅢ-the cracks extended along the interface direction and the loading direction of coal-backfilling structure sample.The splitting failure mechanism of coal-backfilling structure was reflected as follows:The load on the interface of coal-backfilling structure had reached the compressive strength,tensile strength or shear strength of interface,causing the crack throughout of interface and leading to the TypeⅠfailure.The load on the coal body element firstly reached its tensile strength,and tensile cracks were generated earliest.As the load continued to increase,the load on the backfilling body element also reached its own tensile strength.The throughout-cracks were extended along the loading direction and the TypeⅡfailure occurs.The tensile cracks were generated earlier in the coal body element because the load on
作者
史旭东
王凯
白锦文
曹光明
冯国瑞
王泽华
崔博强
宋诚
SHI Xudong;WANG Kai;BAI Jinwen;CAO Guangming;FENG Guorui;WANG Zehua;CUI Boqiang;SONG Cheng(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention,Taiyuan,Shanxi 030024,China;Shanxi Coking Coal Group Co Ltd,Taiyuan,Shanxi 030024,China;Shanxi Research Institute for Clean Energy,Tsinghua University,Taiyuan,Shanxi 030032,China)
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2023年第2期387-398,共12页
Journal of Mining & Safety Engineering
基金
国家杰出青年科学基金项目(51925402)
国家自然科学基金项目(52174125)
山西省优青培育基金项目(20210302122008)
山西省科技重大专项项目(20201102004)。
关键词
煤充结构体
劈裂破坏
界面角度
煤体元件
充填体元件
coal-backfilling structure
splitting failure
interface angle
coal body element
backfilling body element
