石灰改良土的非饱和土变形与强度特性试验  

Experimental study on strength and deformation of unsaturated soil of lime treatment

作　　者：罗小艳[1,2] 扶名福 

机构地区：[1]南昌大学建筑工程学院,江西南昌330031 [2]江西科技师范大学建筑工程学院,江西南昌330013

出　　处：《人民长江》2017年第17期86-90,共5页Yangtze River

基　　金：国家自然科学基金项目(51468041;51268046);江西省自然科学基金项目(20161BAB203078);教育部博士点专项基金项目(20123601110001)

摘　　要：为研究石灰含量与颗粒级配对非饱和改良土强度和变形的影响,利用非饱和三轴仪对石灰改良花岗岩残积土进行控制吸力固结排水剪切试验,研究掺灰比0%,4%和8%的改良花岗岩残积土的强度和体变特性,同时还选用了颗粒粒径小于1 mm与小于2 mm的土料进行了相关试验。研究结果表明:石灰含量和净围压对非饱和改良土的应力应变曲线均有较大影响,且曲线呈硬化型;相同石灰含量下非饱和改良土的强度峰值随着净围压的增大而增大;在净围压相同时,强度峰值随着石灰含量的增大而增大;在同基质吸力时,凝聚力和内摩擦角随着石灰含量的增加而相应增大,凝聚力增加更明显。在相同基质吸力、干密度、石灰含量下,颗粒粒径小于1 mm与小于2 mm的土料应力应变关系接近,细粒土的颗粒尺寸对强度影响小。非饱和土的体变特性受石灰含量和净围压的影响明显,对于细颗粒土,其结果受颗粒粒径的影响小。In order to study the influence of lime content and gradation on deformation and strength of unsaturated soil, a series of drainage and consolidation tests were performed for unsaturated lime - treated granite residual soil under suction - controlled conditions by the unsaturated soil triaxial apparatus. The experimental program consists of 0% , 4% , 8% lime content and grade sizes of 〈 1 mm and 〈 2 mm. The results indicate that the lime content and net confining pressure have significant influence on the stress and strain relationship of unsaturated soil, and the stress - strain relation curves are hardening type. For the same lime content, the peak strength increases with net confining pressure, while for the same net confining pressure, the peak strength in-creases with the lime content. The cohesion and friction angle of the lime - treated soil increase with the lime content, and the in-crease of cohesion is more obvious. Under the same suction, dry density and lime content, the soil of granular size 〈 1 mm and 〈 2 mm have the similar stress - strain relation, indicating that the granular size has small effect on the relationship of the stress and strain. The volumetric strain of unsaturated soil is significantly influenced by lime content and net confining pressure. For fine soil, its characteristics are less influenced by particle size.

关 键 词：非饱和土 花岗岩残积土 基质吸力 三轴试验 石灰改良 

分 类 号：P642[天文地球—工程地质学]