颗粒破碎对绢云母片岩强度和变形影响的试验研究  

Experimental study of effect of particle breakage on strength and deformation of sericite schist

作　　者：秦尚林[1] 杨兰强 陈荣辉[1] 陈善雄[1] 

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071 [2]浙江省工程勘察院,浙江宁波315000

出　　处：《岩土力学》2014年第11期3086-3092,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51079142);中国科学院重点部署项目(No.KZZD-EW-05);湖北省谷城至竹溪高速公路科技项目(No.GZL-KJ-02-01)

摘　　要：为进一步弄清颗粒破碎对软岩粗粒料强度、变形的影响,开展2组不同初始干密度下的绢云母片岩粗粒料的固结排水三轴试验,分析了绢云母片岩粗粒料颗粒破碎规律,并探讨了颗粒破碎对绢云母片岩粗粒料力学性质的影响。结果表明,绢云母片岩粗粒料相对破碎率随围压的增加而增大,但颗粒破碎增幅速率受初始干密度影响较大,颗粒破碎与围压之间的关系可用线性关系描述;由于初始孔隙率的影响,使得试样在同一应力水平下高密度试样颗粒破碎明显高于低密度试样;颗粒破碎对高密度试样抗剪强度降低的影响高于低密度试样,导致两种干密度试样的应力-应变曲线在某处出现相交,最终出现初始密度低的试样抗剪强度大于初始密度高的试样抗剪强度的现象;高密度试样孔隙率较小,其剪胀因子一直保持在1附近,而低密度试样孔隙率较大,受颗粒破碎和剪胀的影响迟缓一些,低密度试样体变较高密度要大些,但整体上由于颗粒破碎和剪胀的影响,绢云母片岩粗粒料的体变均不大。In order to further claril~ the etlect ot particle breakage on strength and detormatlon ot sort rock coarse aggregates, consolidation drained triaxial shear tests of two groups of different initial dry densities of sericite schist coarse aggregates are carried out. The law of particle breakage and its influence on mechanical properties of sercite schist coarse aggregates are discussed. The result shows that the relative particle breakage index of sercite schist coarse aggregates increases with confining pressure. But the growth rate of particle breakage is greatly influenced by the initial dry density. The relationship between particle breakage and confining pressure might be described by a linear function. The particle breakage of high density samples is significantly higher than low density samples under the same stress level because of the influence of the initial porosity. So influence of particle breakage on shear strength decrease under the high density is higher than the influence of low density samples; this might cause stress strain curve of two different dry densities to intersect somewhere. Finally, the shear strength of low density is greater than the high density samples. The porosity of high density sample is small and its dilatancy factor always stay near 1.The porosity of low density sample is larger and the particle breakage and dilatancy delay the impact on its dilatancy factor. So the lower density of samples, the larger volume change is. However, the volume change is very small because of the influence of particle breakage and dilatancy of sericite schist coarse aggregates.

关 键 词：绢云母片岩 相对破碎率 不同干密度 抗剪强度 剪胀因子 

分 类 号：TU452[建筑科学—岩土工程]