黄土的增湿变形特性及其与结构性的关系  

MOISTENING DEFORMATION CHARACTERISTIC OF LOESS AND ITS RELATION TO STRUCTURE

作　　者：陈存礼[1] 高鹏[1] 胡再强[1] 

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048

出　　处：《岩石力学与工程学报》2006年第7期1352-1360,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：陕西高校省级重点实验室重点科研项目(03JS038);西安理工大学高学历人员科研启动基金项目(220603)

摘　　要：在不同含水量下对西安、兰州原状黄土进行压缩试验,根据同一压力下原状黄土与重塑饱和黄土的孔隙比定义一个定量结构性参数mP,探讨黄土的结构性参数随压力及增湿含水量w变化的特性,用结构性变化特性分析原状黄土增湿变形特性机制。研究表明:(1)同一压力下,mP-w关系可分为平缓和下降2段,而增湿湿陷系数δs′与w的关系可分为平缓和增长2段,交点处的增湿结构破坏起始含水量wf随压力的增大而减小。(2)在w<wf时,黄土对水的敏感性很弱;w>wf时,水的敏感性很强。(3)高压力处增湿湿陷性强,低压力处增湿湿陷性弱,增湿压力的影响在低初始含水量时要比高初始含水量时明显得多。(4)同样增湿含水量下,增湿变形随着初始含水量w0增大而减小,但当w0<wf时,w0变化对增湿湿陷变形的发展几乎没有影响,可以归一。(5)在不同压力和初始含水量下,西安、兰州黄土的δs′-(mP,w0?m P,w)之间的线性关系非常相近,即增湿变形的发展受结构性影响的规律是基本相同的。ComPression tests are conducted on intact loess obtained from Xi＇an and Lanzhou with different water contents. The quantitative comPrehensive structural parameter mP is defined by using porosity ratio of intact and disturbed saturated loess under the same pressure. The effects of moistening water content w and pressure on the structural parameter are investigated. The mechanism of moistening deformation is analyzed using characteristics of the structural parameter change. The study indicates that. （1） the structural parametermP decreases and coefficient of moistening collapsibility δs increases during moistening process under condition of the same pressure, but they scarcely change when moistening water content w is less than the initial moistening water content with structure destruction ωf which locates at the turn point and decreases with the increase of pressure. （2） when w is less than ωf, water sensitivity of loess is very weak, but it is very strong when ω is large than ωf. （3） moistening collapsibility is greater under high pressures, and it is weaker under low pressures. The effect of pressure on moistening collapsibility is more obvious at small initial water content than that at large one. （4） moistening deformation decreases with the increase of initial water content ω0 under the same ω, but its change has no effect on the deformation when ω0 is less than ωf. （5） the linear relations between δs and （mP, ω0 -mP, ω） is almost the same for Xi＇an loess and Lanzhou loess under the condition of different pressures and initial water contents. Namely, structure nearly has identical influence on the growth of moistening deformation under different conditions.

关 键 词：土力学 黄土 压缩试验 增湿变形 结构性参数 

分 类 号：TU444[建筑科学—岩土工程]