千枚岩倾倒变形岩体饱水软化效应试验研究

Study on saturated softening effect of phyllite toppling deformation rock mass

随着越来越多大型、巨型水电工程建设与蓄水运行,广泛分布于库区的大规模深层倾倒在库水长期浸泡作用下的稳定性如何也受到越来越多的关注。千枚岩作为一种软岩,由其组成的倾倒变形体在遇水后容易变形失稳。本文通过室内实验的手段,首先对不同倾倒程度的千枚岩体的物理性质指标进行了对比,然后通过单轴压缩、三轴压缩实验对不同倾倒程度的千枚岩体在不同饱水时间条件下的力学性质的变化开展了研究,最后归纳总结了千枚岩倾倒变形岩体的饱水软化效应。结果表明:(1)千枚岩的破碎程度随饱水时间增加而增大;(2)饱水后千枚岩的单轴抗压强度、峰值应力、抗剪强度等力学参数相比于干燥状态的岩石都会降低;(3)倾倒变形程度小的千枚岩,其力学参数衰减幅度要大于倾倒变形程度大的千枚岩,说明水对倾倒变形程度小的千枚岩力学性质影响更大。本文成果可对千枚岩倾倒变形体在库水长期作用下的软化失稳机理提供一定的参考。

With the construction of more and more large and giant hydropower projects and the operation of water storage,the stability of large-scale deep dumping widely distributed in the reservoir area under the long-term immersion of reservoir water will also attract more and more attention.As a soft rock,phyllite is easy to deform and lose stability when it encounters water.By means of laboratory experiments,this paper firstly compares the physical properties of phyllite with different dumping degrees.Then,through uniaxial compression and triaxial compression experiments,the change of mechanical properties of phyllite with different dumping degrees under different water saturation time was studied.Finally,the water-saturated softening effect of phyllite dumping deformed rock mass is summarized.The results show that:(1)the degree of fragmentation of phyllite increases with the increase of water saturation time;(2)the uniaxial compressive strength,peak stress,shear strength and other mechanical parameters of phyllite after water saturation are all lower than those of dry rock;(3)For phyllite with a small degree of dumping deformation,the attenuation of its mechanical parameters is greater than that of phyllite with a large degree of dumping deformation,indicating that water has a greater impact on the mechanical properties of phyllite with a small degree.The results of this paper can provide a certain reference for softening and instability mechanism of phyllite dumping deformed body under long-term action of reservoir water.