摘要
针对经历了＂5·12＂汶川大地震的裂隙岩体,利用MTS岩石力学试验系统开展裂隙岩体介质的单轴动力加载试验,试验开始阶段对汶川实测地震波进行概化分析,将其分解为不同频率及振幅的正弦波,研究了裂隙岩体介质在先期随机地震作用下的动力特性。结果表明,随机地震作用下,岩体应力—应变曲线具有良好的光滑性;当裂隙连通率较大时,倾角在30°～60°范围内,随着倾角的减小,曲线的延展性增强;当裂隙连通率较小时,应力—应变曲线延展性减弱,且受倾角影响较小。裂隙岩体经过先期地震作用,峰值强度受裂隙倾角影响较小,主要随裂隙连通率的增大而减小;当倾角为30°时,峰值强度取得极小值。当裂隙连通率较大时,弹性模量在不同倾角下的变化不明显;当裂隙连通率较小时,弹性模量在倾角为30°和60°处取得极小值。当裂隙倾角较小时,峰值强度和弹性模量与连通率呈非线性规律;当裂隙倾角较大时,则随连通率变化呈线性规律。裂隙岩体的强度与破坏形态有关,当试样发生剪切破坏时,试样强度较低。
Aiming at the fracture rock masses suffered＂5·12＂Wenchuan earthquake,uniaxial dynamic loading test of rock medium was carried out by using the MTS system.Meanwhile,this paper further studied the mechanical properties of the rock medium under pre-earthquake.At the beginning of experiment,to achieve the process of dynamic grade loading on MTS rock mechanical testing system,the researcher conducts the generalization analysis on the measured seismic waves,and divides the waves into sine waves which have different frequency and amplitude.Experimental research indicates the following results：Under the seismic wave motion,the stress-strain curve of rock mass has good smoothness.When the fracture connectivity rate is rather higher and the inclination angle is within the range of 30°to 60°,the ductility of curve increases with the decreasing of the inclination angle.While the fracture connectivity rate is rather low,the ductility of stress-strain curve decreases generally and has less relationship with the angle.The peak strength of specimens has less relationship with the angle,but it increases with the decreasing of fracture connectivity rate.At the same fracture connectivity rate,the peak strength gets the minimum when the angle equals to 30°.When the fracture connectivity rate is higher,the elastic modulus of specimens does not vary obviously under different angle.On the contrary,when the fracture connectivity rate is lower,the elastic modulus has the minimum with the angle is 30°or 60°.When the fracture angle stays at a low level,the peak strength and the elastic modulus of specimens appears nonlinear relationship with the small fracture inclination angle.While the fracture angle stays at a high level,there is a linearity relation between peak strength and elastic modulus with the fracture connectivity rate.The peak strength of fractured rock masses is related to its failure mode.The peak strength of rock will result in the minimum when there is a shear failure.
出处
《水电能源科学》
北大核心
2016年第1期123-127,共5页
Water Resources and Power
基金
国家自然科学基金项目(51079092)
关键词
裂隙岩体
先期地震
单轴压缩试验
倾角
连通率
强度特性
破坏形态
fracture rock masses
pre-earthquake
uniaxial compression test
fracture inclination angle
fracture con nectivity rate
strength characteristics
failure mode
