干湿循环作用下砂岩力学特性及能量损伤演化

内陆港口砂岩地基在水的循环作用下,岩石力学性能劣化,威胁港口地基的长期稳定性。为探究砂岩在干湿循环作用下的力学特性及能量损伤,开展不同干湿循环次数下的三轴压缩试验。结果表明:随着干湿循环作用的增强,砂岩力学性能指标逐渐衰减,当循环次数达到15次时,衰减幅度基本收敛;砂岩峰值强度、残余强度、弹性模量和变形模量的劣化度累积具有相似规律,干湿循环0~8次时累积速率较快,循环次数达到15次时累积速率放缓;在应力作用下,岩石吸收总能量随着应变增长而逐渐递增,耗散能累积主要集中在岩石破坏阶段。能量耗散导致损伤发展,损伤变量与耗散能走势较为一致。

Mechanical properties and energy damage evolution of sandstone under dry-wet cycle

Under the action of water circulation,the sandstone foundation of inland port leads to the deterioration of rock mechanical properties and threatens the long-term stability of port foundation.In order to explore the mechanical characteristics and energy damage of sandstone under dry-wet cycle,we carry out the triaxial compression test under different dry-wet cycle times.The results show that with the enhancement of dry-wet cycle,the mechanical properties of sandstone gradually decay,the attenuation amplitude basically converges when the number of cycles reaches 15 times.The accumulation degrees of deterioration of sandstone peak strength,residual strength,elastic modulus and deformation modulus have the similar law,the accumulation rate of dry-wet cycle is faster when 0~8 times,and the accumulation rate slows down when 15 times.Under the action of stress,the total energy absorbed by rock increases with the increase of strain,and the accumulation of dissipated energy is mainly concentrated in the failure stage of rock.Energy dissipation leads to damage development,and the trend of damage variable and dissipated energy is consistent.