改性黄土的冻融特性  

Properties of modified loess under freeze-thaw cycles

作　　者：吕擎峰[1] 李晓媛[1] 赵彦旭 王生新[3] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [2]中国铁建二十一局,甘肃兰州730000 [3]甘肃省科学院地质自然灾害防治研究所,甘肃兰州730000

出　　处：《中南大学学报（自然科学版）》2014年第3期819-825,共7页Journal of Central South University:Science and Technology

基　　金：甘肃省科技支撑计划项目(1011FKCA093);中国铁建科技支撑计划项目(12-C32)

摘　　要：研究冻融循环前后不同水泥石灰粉煤灰配比下改性黄土的无侧限抗压强度、渗透系数和微观结构等物理力学特性的变化。综合考虑强度、渗透性和抗冻融．胜能，提出改性黄土改性剂的最优配比，探讨冻融循环对改性黄土工程特性的影响。结果表明：在考虑冻融循环的条件下，4％-5％的水泥与6％的石灰及10％的粉煤灰的掺入不仅能有效地提高改性土的抗压强度，降低渗透系数，而且能够避免改性黄土因为刚性太大而引起的抗冻融能力下降的情况。3种改性剂的联合作用改变了黄土颗粒的排列和连结方式，从而能够提高改性黄土的强度和抗冻融能力。The modified loess physical and mechanical characteristics such as unconfined compressive strength, permeability coefficient and microstructure were tested under the freeze-thaw cycles of modified loess. According to the comprehensive strength, permeability and freeze-thaw resistance performance of the modified loess, the optimal ratio of the modifier and the influence of freeze-thaw in practical application were proposed. The results show that the loess by adding 4%-5% cement, 6% lime and 10% fly ash can not only has higher compressive strength and lower permeability coefficient, but also can avoid the decreasing of freeze-thaw resistance ability caused by its large stiffness. The micro experiment indicates that combined effect of the three modifiers can change arrangement and bond of soil particles, thus the strength and freeze-thaw resistance ability of modified loess are reinforced.

关 键 词：改性黄土 冻融循环 强度 渗透性 微观结构 

分 类 号：TU599[建筑科学—建筑技术科学]