【作者】 孙明星；

【导师】 党进谦；

【作者基本信息】 西北农林科技大学 ， 岩土工程， 2008， 硕士

【摘要】 氯盐渍土具有较强的溶陷性,水在其中扮演着重要的角色。大多数研究者都基于饱和土和非饱和土两者的压缩量来研究溶陷性,但没有研究在浸水过程中盐渍土土体的变形特性。由于盐渍土的溶陷特征和黄土的湿陷特征很相似,所以本文参考黄土的浸水试验研究方法,对盐渍土的浸水特性进行了初步研究。本文首先在靖边、延安、杨凌和洛阳黄土中选择了洛阳黄土作为母本土样,并选择氯化钠盐作为氯盐在室内配制了5种含盐量的盐渍土;并对这5种盐渍土进行了基本物理性质、化学性质和击实特性的研究。结果表明:土粒比重随含盐量的增加而减小,基本上呈线性关系。随着含盐量的增加,液、塑限呈减小趋势。含盐量在4%以前,含盐量对交换性钠有较大影响。最大干密度在含盐量达到8%时出现最大值。最优含水率随含盐量的增加逐渐减小。从流变角度分析了压缩试验结果,认为在研究压力范围内重塑室内盐渍土的蠕变属于衰减蠕变。各应力水平下变形的总体趋势大致相同,基本呈双曲线关系;并探讨了影响盐渍土压缩性的几个主要因素,包括干密度、固结压力和含盐量。通过分级浸水试验,研究了在浸水过程中增湿变形量的变化过程,并分析了影响增湿变形量的主要影响因素。结果表明:浸水压缩过程可以分为三个阶段:水分扩散阶段、增湿变形发展阶段和变形稳定阶段。干密度、压力、含盐量和含水率是增湿变形量的重要影响因素。参考黄土增湿剪切试验,对同一含盐量不同干密度的试样进行了增湿剪切变形试验。试样在不同剪应力作用下分级浸水后,每级含水率下的变形量随着时间的延长而逐渐增大,但增长速率愈来愈小,趋于零,即在一定时间后变形量达到一稳定值。达到稳定的时间则随着压力、压力比和含水率的不同而有所不同。相同条件下,压力愈大,稳定时间越长;压力比越大,稳定时间越长;随着浸水量的增加,土样的含水率增大,稳定时间越长。干密度、剪应力水平和含水率是影响增湿剪切变形量的主要因素。更多还原

【Abstract】 Chlorine saline soil is highly collapsible.water plays an important role in collapse. The properties of saline soil is studyed based on the difference value of compress deformation before and after saturated, but the properties in the soaking process is no in-depth study. Since the dissolution of saline soil and the collapsible loess has very similar characteristics, the method studying the properties of saline soil in the soaking process is reference to the Loess moistening test method.In this paper, Luoyang loess is choosen as the female parent soil form Jingbian, Yan’an, Yangling and Luoyang Loess, and sodium chloride is choosen as salt chloride. Making up five kinds of saline soil by fixing the female parent soil and salt according to different ratio. The basic physical properties, chemical properties and compaction properties of the five kinds of saline soil were studied. The results showed that: the relative density of soil with the increase of salt content reduced, basically is described a linear function. With the increase of salt content, liquid, plastic limit was decreasing trend. Before salinity reached 4 percent, the salt content has a great influence on the exchange of sodium. The greatest drying density is got when the salt content has reached eight percent. The optimum water content gradually decreased with the increase of salt content.The result of compression test of saline soil is analysised from rheological theory. The results showed that the creep behavior belong to decay creep within the testy consoldition pressure. The overall trend of deformation at various stress is the same. The relationship between deformation and time is described a hyperbolic function. And several major factors effecting the deformation, including dry density, consolidation pressure and salinity, are studied.Through grading soaking experiment, the moistening deformation process duaring the soaking is studied, the main factors ,including dry density, consolidation pressure, salinity and water content, effecting the moistening deformation is analysised. The results showed that: the soaking compression process can be divided into three phases: the diffusion of water, the development of mositening deformation and deformation stability.With reference to the test of moistening loess shear, the samples which are the same salt content and different density are experimented. The deformation of each step is gradually increased with time after the sample is immersing by step, and the growth rate are smaller and smaller, tending to zero, that is, the deformation is achieved a stable value in a certain time. The time achieved stability is effected by pressure and pressure ratio and water content. On the same conditions, the greater the pressure, the longer the stability time ; the greater the pressure ratio, the longer the stability time; the greater the water content, the longer the stability time. Dry density, shear stress ratio and water content are affected on mainly shear deformation.更多还原