摘要
压缩系数、压缩模量是评价土的压缩性的两个非常重要的参数指标,对于地基沉降计算具有重要意义。然而在实际工作中对于确定压缩性指标的方法上还存在一定的问题。本文从压缩系数、压缩模量的定义出发,对土的压缩模量、压缩系数及孔隙比之间的关系进行理论分析,推导了三者之间的两种关系式,分析了三者之间的对应关系。以合肥地区的弱膨胀性黏土为研究对象,通过6组不同饱和度下的黏性土样的多循环加卸载快速固结试验,讨论了快速固结试验中常用的变形量校正方法存在的问题,提出了改进的校正系数计算方法。探讨了土样压缩指标与加卸载循环次数及土样饱和度的关系,对压缩模量与饱和度之间的关系采用指数函数进行了曲线拟合,并对曲线拟合系数进行了概率统计分析。研究结果表明:随着加卸载循环次数的增加,土样由塑性状态向弹性状态过渡;压缩模量随着饱和度的增加而减少,并逐渐趋于稳定。
The compression coefficient and compression modulus are two important parameters of soil to evaluate the compressibility of soil. They are of great significance to the calculation of soil settlement. However,there are still some problems in the method of determining the compressibility index of soil in practice. Based on the definition of the compression coefficient and the compression modulus, this paper theoretically analyzed the relationship of the compression coefficient,compression modulus and the void ratio of soil. Two kinds of the calculation formula about these three parameters were also derived. Then these corresponding relations among the compression coefficient,compression modulus and the void ratio of soil were studied. This paper takes the weak swelling cohesive soil in Hefei area as the research object. The fast-consolidation tests of six sets of cohesive soil samples from Hefei with different saturation were carried out through multi-cycle loading and unloading. The problem of amending formula of deformation commonly used in the fast-consolidation test was pointed out and then the improved method was proposed. The correlation of the compression index,the number of loading and unloading and the degree of saturation were discussed. Then the exponential function was used to fit the relationship betweenthe compression modulus and the degree of saturation. Using the probabilistic method,the fitting coefficients were obtained. The results show that the soil samples transmit from plastic state to elastic state with the increase in the time of loading and unloading cycle. With the increase of the degree of saturation,the compression modulus decrease gradually until come to stable.
出处
《工程地质学报》
CSCD
北大核心
2017年第5期1336-1343,共8页
Journal of Engineering Geology
基金
国家自然科学基金项目(41572282)
安徽省自然科学基金面上项目(JZ2015AKZR0045)资助
关键词
压缩模量
压缩系数
固结试验
含水率
饱和度
Compression modulus, Compression coefficient, Consolidation test, Water content, Degree of saturation
