煤矿安全2024，Vol.55Issue(1)：57-64,8.DOI:10.13347/j.cnki.mkaq.20221325
基于黏聚力单元的煤岩复合体水力压裂裂纹扩展规律研究
Study on crack propagation law of hydraulic fracturing of coal rock complex based on cohesive element
摘要
Abstract
In order to further analyze the propagation path and evolution law of hydraulic fractures in coal rock complex,from the perspective of stress field,coal rock interface strength and coal seam bedding dip angle,a hydraulic fracture model of coal rock com-plex is established based on cohesion unit method,and the propagation law of hydraulic fractures in coal rock complex under differ-ent working conditions is analyzed.It is found that after the hydraulic fracture of coal rock complex cracks in the overlying strata,with the gradual increase of the stress difference between σy and σx,the hydraulic fracture is more and more significantly controlled by the stress field.When the strength of coal rock interface is small,it is difficult for hydraulic cracks to form water pressure accu-mulation in the interface to reach the cracking conditions of coal seams.When the strength of coal rock interface is large,it can ex-pand a certain distance in the coal rock interface and complete pressure holding.When the pressure reaches the cracking conditions of coal seams,water pressure cracks pass through the coal rock interface and induce the crack initiation and expansion of coal seams.Under the condition of 30° dip angle of coal seam bedding,hydraulic fractures form main fractures along the direction of main stress and secondary branch fractures along the direction of bedding.Under different geological conditions,stress field,coal rock interface and coal bedding have different control effects on hydraulic cracks,so they can be effectively combined to form a complex crack net-work structure.关键词
煤岩复合体/水力压裂/交界面强度/黏聚力单元/裂纹扩展Key words
coal rock complex/hydraulic fracturing/interface strength/cohesive element/crack propagation分类
矿业与冶金引用本文复制引用
张照伟..基于黏聚力单元的煤岩复合体水力压裂裂纹扩展规律研究[J].煤矿安全,2024,55(1):57-64,8.基金项目
国家自然科学基金面上资助项目(51874125) （51874125）
