不同加载速率对石灰岩巴西劈裂特性的影响  

Effects of different loading rates on Brazilian tension characteristics of limestone

作　　者：王成[1] 王春[1,2] 苏承东 熊祖强[1] WANG Cheng;WANG Chun;SU Chengdong;XIONG Zuqiang(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo,Henan 454003,China;State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization,Jiaozuo,Henan 454003,China)

机构地区：[1]河南理工大学能源科学与工程学院,河南焦作454003 [2]煤炭安全生产与清洁高效利用省部共建协同创新中心,河南焦作454003

出　　处：《采矿与安全工程学报》2021年第5期1036-1044,共9页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(52074101,51904093);河南省重点研发与推广专项项目(202102310217,192102310247);河南省高校重点科研项目(20A440007,21A440010)。

摘　　要：利用RMT-150B岩石力学试验系统进行了6种加载速率下石灰岩圆盘试样的巴西劈裂试验,分析了圆盘试样劈裂破坏过程中的变形、强度、能量和破坏特征与加载速率的关系。试验表明:整个加载劈裂过程中压应力-压应变曲线大致可分为压密、弹性和破坏3个阶段,拉应力-拉应变曲线大致可分为弹性和破坏2个阶段,峰值前拉应力-拉应变始终保持良好的线性关系,平均峰值压应变、拉应变与加载速率没有明显关系。加载速率对试样劈裂强度、劈裂能率的影响大致相同:加载速率(0.005~0.5 kN/s)较低时,劈裂强度、劈裂能率随加载速率增加较为缓慢;加载速率(4.78~58.8 kN/s)较高时,劈裂强度、劈裂能率随加载速率增加较快,采用对数函数能够表征三者的关系,且劈裂强度与劈裂能率呈正相关,加载速率为0.005~58.8 kN/s范围内大多数圆盘试样劈裂成对称半圆,劈裂破口面宏观特征与加载速率关系不明显。Brazilian tension experiments on limestone disc specimens under six loading rates were carried out with RMT-150B rock mechanics test system.The influences of loading rates on specimen deformation,crack behaviour,splitting strength,energy,and damage characteristics were analyzed.Experimental results have shown that the compressive stress-strain curve can be roughly divided into 3 stages:compaction,elastic stages,and fracture stage.And the tensile stress-strain curve approximately consists of elastic stage and fracture stage.Tensile stress increases linearly with tensile strain before peak stress,and there is no obvious relationship between average peak compressive strain,tensile strain,and loading rate.The loading rate influences the tensile strength and splitting energy ratio in the same manner:splitting tensile strength and splitting energy ratio increases slowly as loading rate increases from 0.005 kN/s to 0.5 kN/s.Within the loading rate of 4.78—58.8 kN/s,splitting strength,splitting energy ratio increase rapidly with the loading rate.Average tensile strength has a logarithmic function relationship with splitting strength and splitting energy.Most disc samples were split into symmetric semicircular and loading rate has no obvious influence on tension failure characteristics within the loading rate of 0.005—58.8 kN/s.

关 键 词：石灰岩 加载速率 巴西劈裂 劈裂强度 劈裂能率 

分 类 号：TU[建筑科学]