冻融循环对饱水岩石纵波波速影响的试验研究

为探究冻融作用对饱水岩石纵波波速与损伤变量的影响规律,在冻结温度为-20℃、融解温度为20℃的条件下,对饱水砂岩、黑云变粒岩、闪长岩和灰岩开展了40次的冻融循环试验。结果表明:在相同的冻融条件下,岩石的矿物成分、胶结类型、孔隙特征、矿物颗粒的排列方式对岩石的纵波波速和损伤变量均产生重要影响;经历40次冻融后,砂岩、黑云变粒岩、闪长岩和灰岩的纵波波速较饱水岩样分别降低了42.12%、14.30%、23.21%和19.24%;纵波波速和损伤变量降低幅度在前5个冻融周期降低较为明显,随冻融次数的增加,纵波波速与损伤变量的降低幅度逐渐减小并趋于稳定。

Experimental Study on the Influence of Freeze-thaw Cycles on Longitudinal Wave Velocity of Saturated Rock

In order to investigate the effect of freeze- thaw cycles on the longitudinal wave velocity and the damage variable of saturated rock，40 freeze-thaw cycles were carried out on saturated sandstone， black cloud granulite， diorite and limestone under the condition of freezing temperature at -20 oC and melting temperature at 20 oC. The results show that the mineral composition， cementation type， pore characteristics， and the arrangement of mineral particles have a significant influence on the longitudinal wave velocity and damage variable of the rock under the same freeze-thaw conditions； after 40 freeze-thaw cycles， the longitudinal wave velocity of sandstone， black cloud granulite， diorite and limestone were decreased by 42.12%， 14.30%， 23.21% and 19.24% respectively compared with that of saturated rock samples； the reduction of longitudinal wave velocity and damage variable is more obvious in the first 5 freeze-thaw cycles. With the increase of freezing thawing times， the decreasing amplitude of the longitudinal wave velocity and the damage variable gradually decreases and tends to be stable.