循环荷载作用下岩石损伤试验研究

Experimental study on rock damage under cyclic loading

针对循环荷载作用下的岩石损伤特性,对岩石进行循环加卸载试验,基于加卸载响应比探究岩石损伤演化规律,得出如下结论:在分级循环加卸载过程中,试件在1级加卸载时损伤量很大,进入2级加卸载之后,损伤量相对较小,且增加缓慢,而围压越大损伤量均值增加也越缓慢,而其破坏也越加彻底。试件在1级加卸载过程中方差最大,其后的加卸载中方差曲线逐渐趋于水平。在试件破坏后期,方差会有回弹。在加卸载过程中试件会出现膨胀—收缩—膨胀的循环。

For the characteristics of rock damage under cyclic loading, a cyclic loading and unloading experiment of rock is car- fled out, and then the evolution law of rock damage is sudied on the basis of load-unload response ratio, from which it is conclu- ded that during the in-step cyclic loading and unloading, the damage of the specimen is quite large in the first step of loading and unloading, and then the damage of the specimen is relatively small after it coming into the second step of loading and unloading with a slower increase, while the larger the confining pressure is, the increase of the mean value of the damage is to be slower, and that the damage is to be more complete. The variance of the specimen is largest during loading and unloading in the first step, after that the variance curve is gradually to be horizontal. In the later stage of the damage of the specimen, the variation is to rebound. Moreover, a cycle of expansion-contraction-expansion of the specimen is to occur during loading and unloading.