压实花岗岩风化土物理力学性状试验研究  

An experimental study of the physical and mechanical properties of compacted weathered granite soil

作　　者：牛玺荣[1,2,3] 高江平[3] 张恩韶[1] 

机构地区：[1]山西大学土木工程系,山西太原030013 [2]北京航空航天大学交通科学与工程学院,北京100191 [3]长安大学道路结构与材料交通行业重点实验室,陕西西安710064

出　　处：《岩土力学》2016年第3期701-710,共10页Rock and Soil Mechanics

基　　金：中央高校基本科研业务费专项资金(No.310821151111);国家重点基础研究发展计划项目(973计划)(No.2014CB047001);山西省交通科技计划项目(No.08-05);山西大学本科生科研训练计划资助项目(No.2016014353)~~

摘　　要：吕梁山脉东麓花岗岩风化土的工程类型与我国南方以及日本、韩国等地的花岗岩风化土有较大差别。为了对吕梁山压实花岗岩风化土的物理力学性状有较全面认识,通过常规土工试验、X射线衍射试验、大固结试验、大三轴试验等方法,对其击实特性、承载特性、变形特性、剪胀特性、强度特性等进行了分析。结果表明:黏土掺量对花岗岩风化土的击实特性和承载特性影响较大,存在两个不同的黏土掺量界限值(约8%和4%),分别使得试样密实状态和承载能力处于最优;试样不存在膨胀潜势,无膨胀性,为低压缩性材料;压实花岗岩风化土颗粒破碎的特点导致试样二次加载→卸载压缩曲线存在两次明显塑性变形增大的现象;剪切时由于试样内部颗粒历经压密→错动→翻越→破碎的过程,导致不同围压下试样表现出不同的剪胀性;剪切过程中由于颗粒破碎的存在,使得试样表现出强度非线性特点。The weathered granites in the eastern foothills of Lüliang Mountain are significantly different from those occurring in the southern China, Japan and South Korea. To understand comprehensively the physical and mechanical properties of the compacted weathered granite in Lüliang Mountain, a series of laboratory tests including routine soil test, X-ray diffraction test, large consolidation test, large-scale triaxial test and so on is performed to analyze the compaction, load-bearing, deformation, dilatancy and strength characteristics of strongly weathered granite. The experimental results show that the clay content has a remarkable influence on the compaction characteristics of compacted weathered granite and the load-bearing characteristics, and there exist two threshold values of clay content, when the clay content is about 8%, the dry density of the sample reach the maximum, while about 4%, California bearing ratio（CBR） has a maximun value. The soil samples in this study have no expansion potential and their compressibility are generally low. Two salient phenomena of plastic deformation can be observed on the secondary loading and unloading compression curve due to particle breakage of compacted weathered granite. Because the soil particles might undergo compacted, dislocated, overturned or crushed processes, the soil samples show different dilatancy characteristics under different confining pressures. In addition, due to the existence of particle breakage, the strength of sample exhibits nonlinear characteristics.

关 键 词：花岗岩风化土 剪胀 强度 大固结试验 大三轴试验 

分 类 号：U419[交通运输工程—道路与铁道工程]