卵石土力学强度特性试验研究  

Experimental study on mechanical behaviors of coarse-grained soil

作　　者：严耿升[1,2] 王志硕[1,2] 胡向阳[1,2] 周广振[1,2] 赵成[1,2] 

机构地区：[1]国家能源水电工程技术研发中心高边坡与地质灾害研究治理分中心,西安710065 [2]中国电建集团西北勘测设计研究院有限公司,西安710065

出　　处：《工程勘察》2016年第2期17-22,共6页Geotechnical Investigation & Surveying

摘　　要：本文通过对不同深度分布的卵石土进行原位剪切试验，研究表明：随着深度增加，土体的孔隙减小，密实度增加，卵石土发生屈服破坏时，剪切位移逐渐减小，卵石土更易发生塑性变形破坏；泥质微胶结卵石土剪切破坏后，其残余抗剪强度没有明显衰减，应力应变曲线属于应变硬化型；试验场地中，卵石土中卵、砾石含量在60％～80％之间，以卵砾石含量70％为界限，卵石土的抗剪强度主要受到粗粒土控制，细粒土产生的黏聚力占次要作用；由于卵石土颗粒大小相差悬殊，在剪切过程中颗粒之间的咬合力随土体密实度对表观黏聚力影响较大，卵石土的颗粒级配情况对剪切面力学性质起控制作用。The in-situ direct tests of the pebble soil show that with the increase of the depth, the porosity with different depth are carried out. The test results of the soil will decrease and the density will increase. When yield failure of the soil occurs, the shear displacement gradually decreases, and the pebble soil tends to the plastic deformation failure. After shear failing the residual shear strength of the micro argillaceous cementation pebble soil has no obvious attenuation and the stress-strain curve is the strain- hardening type. In the test site, the grait and gravel concentration of the pebble soil is between 60% and 80%. If 70% is considered the threshold level, the shear strength of the pebble soil is controlled by coarse grained soil and the cohesive force controlled by fine grained soils accounts for the secondary role. Due to the difference particle size of pebble soil, the apparent cohesive force exhibits an influence during the shearing process, characterized by an increase in the degree of density and the interlocking force. The grain composition of the pebble soil controls the mechanical orooerties of the shear olane.

关 键 词：粗粒土 原位剪切试验 颗粒级配 应力应变特性 强度特性 

分 类 号：TU443[建筑科学—岩土工程]