摘要
岩石作为一种常见的工程材料,其动态拉伸力学性能的准确核定及破裂机理至关重要,而巴西劈裂试验是目前测定岩石抗拉强度最广泛的试验方法.为探究不同冲击速率下青砂岩抗拉特性及能量利用效率,结合室内试验与细观参数标定,建立了青砂岩宏-细观力学响应关系,分析了青砂岩在不同冲击速率下的力学特性、破裂规律与能量利用效率.结果表明:①青砂岩破裂过程中,碎块内部以拉力链为主,破裂口边缘附近以压力链为主,拉力链在裂纹扩展与延伸中起主要作用,而最终断裂是压力和拉力链相互作用的结果;②随着冲击速率增加,青砂岩破裂形态可分为主裂纹为主、次生裂纹出现、次生裂纹贯穿的破坏形式,而破裂微元体、拉伸与剪切裂纹均呈现增加的趋势.在相同的冲击速率下,破裂微元体呈现出缓慢增加、快速增加与稳定增加阶段,而拉伸与剪切裂纹均呈现快速增加与稳定增加阶段,且在破裂过程中主要为拉伸裂纹;③在冲击速率为2~12 m/s时,能量利用效率呈现快速增加的趋势,12~28 m/s时,能量利用效率呈现出上下波动趋势,28~30 m/s时呈现出下降趋势,在冲击速率为22 m/s时,最大能量利用效率为8.153%.研究结果可为岩石破碎过程中工艺参数的合理选择提供指导.
As a common engineering material,accurately determining the dynamic tensile mechanical properties and fracture mechanisms of rocks is crucial.The Brazilian splitting test is currently the most widely used test method for determining the tensile strength of rocks.This study investigates the tensile properties and energy utilization efficiency of green sandstone under different impact rates by establishing a macro/micro mechanical response relationship through indoor experiments and microscopic parameter calibration.The analysis of green sandstone’s mechanical properties,fracture laws,and energy utilization efficiency under different impact rates reveal the following:①During the fracture process,the internal structure of the green sandstone fragments is mainly composed of tension chains,while the fracture edges consist mainly of pressure chains.Tension chains play a major role in crack propaga-tion and extension,with the final fracture resulting from the interaction between pressure and tension chains.②As the impact rate increases,the fracture morphology of green sandstone can be divided into three types:primary cracks,secondary cracks,and secondary cracks penetrating. The fracture microelements,along with the tensile and shear cracks,showed an increasing trend. At the same impact rate,fractured microelements exhibit slow,rapid, and stable growth stages,while both tensile and shear cracks display rapid and stable growth stages,with tensile cracks being the main ones during the fracture process. ③ Energy utilization efficiency trends vary with impact rates:it rapidly increases from 2 m/s to 12m/s,fluctuates from 12 m/s to 28m/s,and decreases from 28 m/s to 30 m/s. The maximum energy utilization efficiency,8.153%,occurs at an impact rate of 22 m/s. The results of this study provide guidance for the rational selection of process parameters in rock-crushing processes.
作者
赵环帅
潘永泰
王星宇
乔鑫
张永强
李少卓
Zhao Huanshuai;Pan Yongtai;Wang Xingyu;Qiao Xin;Zhang Yongqiang;Li Shaozhuo(School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Engineering Research Center for Mining and Urban Solid Waste Recycling,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《天津大学学报(自然科学与工程技术版)》
北大核心
2025年第6期591-600,共10页
Journal of Tianjin University:Science and Technology
基金
国家自然科学基金资助项目(52074308).
关键词
青砂岩
冲击速率
巴西劈裂
抗拉特性
断裂能
green sandstone
impact rate
Brazil splitting
tensile property
fracture energy
作者简介
赵环帅(1980-),男,博士研究生,副研究员,zhaohuanshuai@163.com;通信作者:潘永泰,panyongtai@cumtb.edu.cn.
