母岩变形特性差异对堆石料力学性质的影响

Influence of Deformation Characteristics of Mother Rock on Mechanical Properties of Rockfill Materials

针对当前研究中很少甚至忽略母岩变形特性对堆石料力学性质的影响,采用大型静力三轴仪及大型渗透仪,分别进行了2种堆石料三轴试验和渗透试验,得到了不同岩性堆石料强度、变形和渗透特性的变化规律,初步分析了母岩变形特性差异对堆石料力学性质的影响机制。试验结果表明:母岩单轴抗压强度相同条件下不同堆石料的强度并不相同,母岩变形特性对堆石料的力学特性同样具有重要影响,主要表现在对于堆石料的强度及变形特性的影响上,而对于堆石料渗透特性的影响则相对较小;影响机制则主要体现在由于母岩变形特性差异导致的堆石料累积体积变形的差异上,堆石料累积体积变形的差异进一步导致母岩弹性模量低的堆石料反而获得较大的峰值强度。建议应从母岩强度和变形特性两个方面研究母岩对堆石料力学特性的影响。

Based on the large-scale static three axis instrument and the large permeability apparatus,the triaxial tests and permeability tests were carried on two kinds of rockfill materials.Finally,the variations of strength,deformation and permeability characteristics in different lithological rockfill materials were obtained,and the influence mechanisms of deformation characteristics of mother rock on mechanical properties of rockfill materials were preliminary analyzed.The result showed that the deformation characteristics of mother rock also played an important role in the mechanical properties of rockfill materials,namely the influence of mother rock on the mechanical properties of rockfill materials mainly lay in the strength and deformation characteristics,while the influence on permeability characteristics of rockfill was relatively small.The strength of different rockfill materials was not the same even though the mother rocks were under the same uniaxial compressive strength.The influence mechanism of deformation characteristics of mother rock on the mechanical properties of rockfill materials was mainly reflected in two aspects:particle crushing and shear shrinkage.The initial deformation index of rockfill materials had a positive correlation with the deformation index of the mother rock,and in the initial stage of shearing,the more the deformation index of mother rock,the faster and the greater the strength of rockfill materials were under the same strain condition,while the cumulative volume deformation and particle breakage were relatively small.With the development of rockfill strain,when a certain stress level was reached,rockfill materials with relatively small deformation index of the mother rock accumulated a relatively large volume deformation due to the shear shrinkage,which led a slow tendency of rockfill materials strength growth was relatively small.While the crushing amount of rockfill materials with large deformation index increased significantly,and led a relatively slow growth of rockfill strength.It was possible to obtain a larger peak strength even the deformation index of mother rock was low.Research conclusions indicated that the influence of mother rock on the mechanical properties of rockfill should be studied from two aspects of strength and deformation characteristics.