摘要
沉降量大且沉降持续时间长是修建在泥炭土地基上的工程所面临的主要问题,而目前国内外学者对泥炭土固结特性的研究结果不尽一致。鉴于此,本文以云南某高速公路泥炭土路段为依托,参照一般土体的室内土工试验方法,对不同有机质含量的泥炭土进行了基本性质试验和一维蠕变试验。结果表明:有机质含量越高,泥炭土的次固结变形量越大。强泥炭质土和泥炭在不同压力下主固结完成时间较短,且基本不受固结压力的影响,这与淤泥质土的相应规律有较大差别。此外,先期固结压力对强泥炭质土和泥炭的次固结沉降速率有很大的影响,而且当荷载大于先期固结压力时,按照一般土体的试验方法进行一维固结试验所得强泥炭质土、泥炭的e-lgt曲线未出现反弯点。弱泥炭质土可参照一般软粘土的方法用e-lgt曲线确定次固结系数,其次固结系数随压力的变化规律与一般软土的变化规律一致,即次固结系数随固结压力先增大后减小。
Large settlement and long-period of settlement duration are the most important problems to be solved during the construction of projects on the peaty soil.Yet,the research results on the consolidation properties of peaty soil were not consistent by now.Directed against the expressway embankment on the peaty soil in Yunnan province,referred to the Code for Highway Geotechnical Testing,some basic tests,such as water content test,unit weight test,specific gravity test,etc.and one-dimensional creep test was conducted in the Lab.The results show that peaty soil has a bigger secondary compression deformation when it has higher organic content.The time to finish the primary consolidation of strong peat soil and peat is very short,and it does not affected by the consolidation pressure,which is different from that of silt soil.Moreover,preconsolidation pressure of the strong peat soil and peat has great effect on the secondary settling velocity.As the load is bigger than the preconsolidation pressure,there is no inflection point on the e-lgt curve of strong peat soil and peat when the one-dimensional consolidation test was conducted referred to the test method of normal soft clay.Secondary compression coefficient of weak peat soil increases at first,and then decreases with the increasing of consolidation pressure,which can be determined on the e-lgt curve.
作者
冯瑞玲
吴立坚
张益铭
Feng Ruiling;Wu Lijian;Zhang Yiming(School of Civil Engineering,Beijing Jiaotong University,Beijing100044,P.R.China;Beijing Key Laboratory of Track Engineering,Beijing Jiaotong University,Beijing100044,P.R.China;Research Institute of Highway Ministry of Transport,Beijing100088,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2019年第5期1384-1392,共9页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(51778048,41371081)
铁路总公司项目(2016G003-B,2017G002-S)
关键词
泥炭土
主固结比
次固结
先期固结压力
peaty soil
primary consolidation ratio
secondary consolidation
preconsolidation pressure
