摘要
With the risk of disappearing for the rock paintings considering long-term exposure in Helan Mountain,the freeze-thaw(F-T)cycling experiments were carried out with 12-hour F-T cycling(0,10,20,30,and 40 F-T cycles)under five kinds of confining pressures(5,10,20,30,and 40 MPa).The acoustic emission(AE)detect technology was used to reveal the rock fracturing characteristics during the triaxial compression test whole process.The stress-strain relation changes along with different confining pressures and F-T cycles.Peak stress and residual stress changes along with different confining pressures and damages,and the variation of axial stress-AE ringing counts-time changes along with different confining pressures and F-T cycles.The damage variable with AE parameter under F-T and force coupling was defined for the first time,and the damages model was established.The experimental results show that the F-T cycles lead to the decrease of rock strength and the gradual transformation of compression failure mode from brittleness to plasticity.The confining pressure provides a certain ability to resist deformation and inhibit crack growth for rock samples after F-T cycles.The temporal and spatial evolution law of AE counts well corresponds to the loading and failure process of the rock samples.The AE 3D positioning technology can accurately capture the development position and direction of internal cracks and pores of rock,and the failure form is conical shear failure.The established damage model has a better fittingness between the theoretical calculation results and the test results,and is reasonable to be used in the future for protection of Helan Mountain rock painting.
作者
杨有贞
ZHAO Yishen
MA Hailong
CHEN Wenwu
FENG Haiyan
JIN Menghua
LIN Qingqing
MA Wenguo
YANG Youzhen;ZHAO Yishen;MA Hailong;CHEN Wenwu;FENG Haiyan;JIN Menghua;LIN Qingqing;MA Wenguo(School of Physics and Electronic and Electrical Engineering,Ningxia University,Yinchuan 750021,China;Institute of Solid Mechanics,Ningxia University,Yinchuan 750021,China;College of Civil Engineering and Mechanics,Lanzhou University,Yinchuan 750021,China;Institute of Ethnic Preparatory Education,Ningxia University,Lanzhou 730000,China;Shanghai Junnel Engineering Co.Ltd.,Shanghai 200030,China)
基金
Funded by the National Natural Science Foundation of China(Nos.11662015,51768059 and 51468053)。
