摘要
为深入研究煤矿开采中开挖速率对煤岩力学及损伤特性的影响,通过自主研发的地声过程模拟试验系统,开展了不同卸荷速率条件下煤岩真三轴卸荷试验。结果表明:随着卸荷速率由0.05 MPa/s增至0.4 MPa/s,煤岩在卸荷破坏时的最大主应变值、最小主应变值及体积应变值分别降低了48.2%、73.8%及113.1%,中间主应变值增加了16.3%;卸荷速率越大,煤岩的扩容现象越明显;煤岩在低卸荷速率条件下的破坏形态表现为剪切破坏,而在高卸荷速率条件下则表现为张剪复合破坏;通过试验数据验证,修正后的Drucker-Prager强度准则对煤岩卸荷破坏更为适用;卸荷速率越大,煤岩在破坏时对应的声发射累计振铃计数越大,能量越高;基于累计振铃计数建立的煤岩损伤演化方程能较好地描述煤岩卸荷过程中的损伤过程,研究结果可为实际工程开挖稳定性预测提供参考。
In order to further study the influence of excavation speed on the mechanical and damage characteristics of coal rock in coal mining,the true triaxial unloading test of coal rock under different unloading rates was carried out through the self-developed geoacoustic process simulation test system.The results show that with the increase of unloading rate from 0.05 MPa/s to O.4 MPa/s,the maximum principal strain value,the minimum principal strain value and the volume strain value of coal rock during unloading failure decrease by 48.2%,73.8%and 113.1%,respectively,and the intermediate principal strain value increases by 16.3%.The larger the unloading rate,the more obvious the expansion of coal rock.The failure mode of coal rock under low unloading rate is shear failure,while under high unloading rate is tension-shear composite failure.The test data show that the modified Drucker-Prager strength criterion is more suitable for the unloading failure of coal rock.The greater the unloading rate,the greater the cumulative ringing count of acoustic emission corresponding to the failure of coal rock,and the higher the energy.The damage evolution equation of coal rock based on cumulative ring count can better describe the damage process of coal rock during unloading process.The research results can provide a reference for the prediction of excavation stabilityinpractical engineering.
作者
彭岩岩
秦奇
宋南
程啸
郦亦凡
PENG Yanyan;QIN Qi;SONG Nan;CHENG Xiao;LI Yifan(School of Civil Engineering,Shaoxing University,Shaoxing,Zhejiang 312000,China;Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province,Shaoxing,Zhejiang 312000,China;MCC5 Group Shanghai Corporation Limited,Shanghai 201900,China)
出处
《矿业研究与开发》
CAS
北大核心
2023年第4期95-102,共8页
Mining Research and Development
基金
浙江省公益技术研究计划/社会发展项目(LGF20D020002)
国家自然科学基金青年基金项目(41702381)。
关键词
煤岩
卸荷速率
真三轴卸荷试验
力学特性
损伤演化
Coal rock
Unloading rate
True triaxial unloading test
Mechanical property
Damage evolution
作者简介
彭岩岩(1987-),女,河南周口人,博士,副教授,主要从事岩体工程物理模拟试验、红外探测技术研究及边坡灾害的预警与控制等研究工作,E-mail:pyy2013www@163.com。
