大理岩干湿循环力学特性试验研究

针对库水变幅带边坡岩体水力风化作用下性能劣化现象,选取锦屏水电站左岸边坡大理岩为研究对象,采用干湿循环处理,开展了单轴和不同围压下的三轴压缩试验,研究了大理岩在不同干湿循环作用下强度、变形和破坏形式等力学特性。试验结果表明:大理岩单轴峰值强度与干湿循环次数呈负相关关系,初次循环阶段的劣化效应显著;较低循环次数下大理岩内摩擦角基本不变,黏聚力有较大幅度下降,总体上黏聚力受干湿循环作用的影响效应比内摩擦角更敏感;干湿循环对大理岩有一定程度的软化作用,多次循环后大理岩弹性模量逐渐降至临界值,围压的增加能有效弱化这种软化作用。

Experimental study on mechanical properties of marble under hydraulic weathering coupling

Aiming at the deterioration of performance under the action of hydraulic weathering of rock mass located in reservoir water fluctuating zone, the marble of Jinping hydropower station is chosen as the re-search object. A series of uniaxial and triaxial compression experimental tests on the marble under dry-wet cycling have been carried out to study the mechanical properties of marble, such as strength, deformation behavior and failure mode. The experimental results show that there is a negative correlation between the uniaxial peak strength of marble and the number of dry-wet circulation, and the degradation effect under the initial stage of cycle is remarkable;the internal friction angle of the marble after a small number of cy-cling times is almost constant, while the cohesion has decreased remarkably. In general, the effect of dry-wet cycling on marble cohesion is more sensitive than internal friction angle. The dry-wet cycling has a certain degree of softening effect on the marble and the elastic modulus of the marble decreases to the critical value after multiple repeated cycles. The increase in confining pressure can effectively weaken the softening effect.