土石堆积体介质力学特性缩尺试验研究  

Composition Effects on Mechanical Properties of Soil-rock Mixtures by Reduced Scale Experiments

作　　者：王秀菊[1] 

机构地区：[1]南京交通职业技术学院建筑工程系,南京211188

出　　处：《三峡大学学报（自然科学版）》2016年第6期35-41,共7页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金"基于细观特征分析的冰水堆积体渐进破坏机理多尺度研究"资助项目

摘　　要：堆积体是由土-石构成的一种不良地质体,其力学特性受块石尺寸、形状、含石率决定的细观结构特征控制.本文通过现场堆积体取样,筛分并配置不同的试验方案,利用室内中型三轴试验研究了含石量、碎石尺寸以及碎石随机位置等对堆积体力学参数与变形特性的影响,得到了不同影响因素下堆积体的应力-应变关系、黏聚力以及内摩擦角变化特征.研究结果表明:堆积体应力-应变关系曲线近似为双曲线,无明显强度峰值,为硬化型曲线;随着碎石尺寸的减小,黏聚力先增大而后减小,但是摩擦角先减小后增大.弹性模量随碎石尺寸增大逐渐增大,泊松比基本保持不变;相同条件下碎石随机位置可导致摩擦角有4°左右的浮动,而黏聚力变化幅度可相差几倍.Soil-rock mixtures are often found in geological deposits. Mechanical properties of these mixtures are controlled by meso-structural characteristics such as rock size distribution, rock shape, locations and content. The effects of material composition on soil-rock mixture mechanical properties were studied in the labo- ratory. Soil-rock material was screened into different size categories. Medium-scale shearing and triaxial ex- periments were used to study the relationships among deformation, strength, content, size and random loca- tion of rocks. The stress-strain curve of soil-rock mixtures is found as a hardening curve which is approxi- mately hyperbola; and there is no obvious peak intensity value. When Mohr-Coulomb criterion is used to depict the curve under a shear strain of 0.15, cohesion first increases then decreases, while the internal friction angle is first decreases then increases. Elastic modulus increases with increase of rock size; but Poisson＇s ratio remained constant. In similar conditions, the random location of rocks can lead to variation range 4 degree of the internal friction angle; and cohesion values can change in a large range than that of the mean value.

关 键 词：堆积体 力学特性 细观力学 缩尺试验 

分 类 号：TU459[建筑科学—岩土工程]