花岗岩的加载速率效应及能量机制研究  

STUDIES ON LOADING RATE EFFECTS AND ENERGY MECHANISM OF GRANITE

作　　者：徐小丽[1,2] 陈琳[3] 高峰[2] 张志镇[2] 

机构地区：[1]南通大学建筑工程学院,南通226019 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,徐州221008 [3]南通大学理学院,南通226019

出　　处：《固体力学学报》2015年第2期154-163,共10页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金资助项目(11202108);中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金(SKLGDUEK1204);南通大学前期预研科研项目(11ZY006)资助

摘　　要：加载速率对岩石的力学性质以及变形破坏方式具有重要的影响.基于MTS810电液伺服材料试验系统与PCI-2声发射仪对岩样进行不同加载速率作用下的单轴压缩和声发射试验.研究结果表明：（1）在各级加载速率作用下,岩样单轴压缩应力-应变曲线大致经历了压密、弹性、屈服、破坏四个阶段.岩样峰后曲线在加载速率为0.001-0.01mm/s时出现台阶型分段跌落状,在加载速率为0.01-0.1mm/s时呈现光滑、陡峭的连续曲线.（2）岩样峰值强度、弹性模量随加载速率的增加而增大,与加载速率对数均呈现三次多项式拟合关系.峰值应变随加载速率的增加而减小,与加载速率对数呈现线性拟合关系.（3）随着加载速率由0.001mm/s增加至0.1mm/s,岩样吸收的总应变能U具有波动性,可释放的弹性应变能Ue增幅60.42%,耗散应变能Ud降幅66.38%,Ue/U增幅43.33%,Ud/U降幅66.67%,岩样破裂模式由拉剪破坏逐渐向张拉劈裂破坏过渡,岩样破裂块数增多.（4）加载速率为0.001-0.1mm/s时,岩样破坏方式有所不同,但破坏为同一类损伤过程.单轴压缩状态下,能量耗散使得岩样损伤致使强度丧失,而能量释放使得岩样宏观破裂面贯通,并向着能量释放的方向张裂或弹射破坏.Loading rate has an important influence on rock mechanical properties and failure modes. U- niaxial compression and acoustic emission of different loading rates on granite were conducted by MTSSl0 servo-controlled testing machine and PCI-2 acoustic emission instrument in this paper, respectively. The resuits showed that： （1） Stress-strain curves of granite under uniaxial compression have four stages including compaction, elasticity, yield and failure. Post-peak curves of the rock sample present stepped and segmented drop shape at loading rates from 0. 001 mm/s to 0. 01 mm/s, and present a smooth, steeper continuous curve at loading rates from 0.01 mm/s to 0.1 mm/s. （2） The peak strength and elastic modulus of rock in- creases with increasing loading rate but the peak strain decreases with increasing loading rate. （3） As the loading rate increases from 0. 001 mm/s to 0.1 mm/s,the total strain energy is volatile,and the rock fracture mode changes from tensile shear failure to tensile splitting failure gradually. （4） When the loading rate from 0. 001 mm/s to 0.1 mm/s,the damage process of rock is the same although the failure mode is different. Under uniaxial compression,energy dissipation renders the rock to damage,but energy release renders the macrofracture surface to be run-through by rifting or catapult destruction in the direction of the energy release.

关 键 词：岩石力学 加载速率 力学性质 应变能 能量耗散与释放 

分 类 号：O347[理学—固体力学]