岩土力学2024，Vol.45Issue(3)：659-673,15.DOI:10.16285/j.rsm.2023.0786
荷载作用下多裂隙煤体力学特性与起裂角研究
Mechanical properties and crack initiation angle of multi-fractured coal under load
摘要
Abstract
This study investigates the influence of fracture geometry and interaction mechanisms on the mechanical behavior of coal under static loading conditions.The digital image correlation method is used as a full-field observation technique,and uniaxial compression tests are conducted on three-crack samples of raw coal prefabricated at different positions using an MTS816 rock servo testing machine.The mechanical properties,crack evolution,and failure characteristics of multi-fractured coal under different position distribution conditions are studied by combining particle flow simulations.Based on the fracture mechanics theory,the influence and applicability of T stress on the multi-fracture tip of coal are discussed.The results show that as the fractures transition from parallel collinear distribution to parallel overlapping distribution,the macroscopic strength of coal samples gradually increases.The distribution form of the fracture affects the pressure state of the coal body,where widely spaced fractures create independent stress weak zones that expand and coalesce as stress increases.Conversely,when fractures tend to overlap,stress concentration areas and weak areas form a unified force system that influences each other.When multiple fractures are collinear or offset distributed,shear stress dominates the fracture surface,and the driving mode supplemented by tensile stress leads to tensile-shear composite failure of coal samples.However,when fractures tend to overlap,shear stress on the fracture surface converts to tensile stress in the rock bridge area,resulting in tensile failure dominated by tensile stress.When considering the influence of T stress,the theoretical prediction value of the crack angle containing three T stress components(Tx,Ty and Txy)is found to be more suitable for studying crack growth angle of multiple fracture tips of finite plate subjected to compression shear stress.关键词
多裂隙煤体/DIC技术/颗粒流模拟/断裂力学/力学特征/扩展角度Key words
multi-fissure coal/DIC technology/particle flow simulation/fracture mechanics/mechanical characteristics/extended angle分类
矿业与冶金引用本文复制引用
王磊,商瑞豪,刘怀谦,陈礼鹏,张宇,王安铖,张帅,刘化强..荷载作用下多裂隙煤体力学特性与起裂角研究[J].岩土力学,2024,45(3):659-673,15.基金项目
安徽高校协同创新资助项目(No.GXXT-2020-055).This work was supported by the Collaborative Innovation Funding Project of Anhui Universities(GXXT-2020-055). （No.GXXT-2020-055）
