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类型 基础研究 预答辩日期 2018-01-25
开始(开题)日期 2014-12-09 论文结束日期 2017-11-18
地点 东南大学岩土工程馆二楼报告厅 论文选题来源 国家自然科学基金项目     论文字数 7.3 (万字)
题目 盐分浸析下海相沉积黏土 力学性状劣化研究
主题词 海相沉积黏土,盐分浸析,液限,灵敏度
摘要 盐分浸析经常引起天然沉积海相软黏土地基沉降过大、滑坡等工程问题,如何定量评价盐分浸析导致天然沉积海相黏土力学性状劣化是实际工程中迫切需要解决的关键问题。本文以低活性天然沉积海相黏土原状样和重塑样为研究对象,开展一系列的物理、化学和力学试验,探讨了孔隙溶液盐分浓度变化对土体物理化学性质、压缩-渗透性状和强度性状的影响规律,建立了盐分浸析引起土体灵敏度变化的定量评价方法。论文主要工作与创新如下: (1)进行不同孔隙溶液盐分浓度下我国沿海地区海相沉积黏土原状样和重塑样的物理-化学试验,探讨盐分浸析对土体物理-化学性质的影响,提出土体液限随孔隙溶液盐分浓度降低呈非线性减小的变化规律,发现盐分浸析基本没有引起化学反应的发生; (2)针对不同孔隙溶液盐分浓度的重塑土进行一系列一维固结-渗透试验和固结不排水试验及落锥试验,研究盐分浸析对重塑土压缩-渗透性状和不排水强度性状的影响规律,探讨盐分浸析引起土体力学性状发生改变的关键影响因素; (3)基于固有压缩-强度理论,建立盐分浸析下重塑土力学性状与物理参数的定量关系,提出简便的海相沉积黏土重塑样压缩参数、不排水抗剪强度和渗透系数的计算方法; (4)对天然沉积海相黏土原状样进行盐分浸析处理,针对处理前后的不扰动样进行一系列的一维固结-渗透试验和不排水剪切试验,分析盐分浸析对天然沉积海相黏土不扰动样力学性状的影响规律,探讨盐分浸析引起原状土力学性状改变程度随应力水平变化的机理; (5)比较原状土与重塑土力学性状随孔隙溶液盐分浓度降低的变化规律,揭示盐分浸析下海相沉积黏土力学性状劣化归结于物理性状变化的机理,提出定量评价盐分浸析下天然沉积海相黏土力学性状劣化的方法。
英文题目 INVESTIGATION OF SALT LEACHING EFFECTS ON MECHANICAL BEHAVIOUR OF NATURAL MARINE CLAYS
英文主题词 marine clays; salt leaching; liquid limit; sensitivity
英文摘要 Soft marine clays are universally distributed around coastal areas, where landslide and large deformation often occurr. It has been well documented that salt leaching during the post-depositional process is the main cause responsible for such kind of engineering disasters. However, how to quantatively evaluate the degradation in the mechanical behaviour of marine clays induced by salt leaching, is still a crucial but unresolved issue. In this study, a series of physical, chemical and mechanical tests were performed on undisturbed and reconstituted specimens of natural marine clays. Salt leaching effects on the physico-chemical, hydro-compressive and undrained shear behaviour of marine clays are investigated, and a method is proposed for evaluating the evolution of sensitivity of marine clays suffered salt leaching. The main works and contributions of this dissertation are highlighted as follows: (1) The physical and chemical properties of soil samples with different pore fluid salinities were measured, including undisturbed and reconstituted marine clays. The salt leaching effects on the physicochemical properties of marine clays are discussed based on the experimental results. It reveals that the liquid limit decreases with the decrease in the pore fluid salinity. Meanwhile, there is little chemical reaction occurred during the salt leaching process; (2) A series of one-dimensional oedometer tests, falling-head conductivity tests, fall cone tests and isotropically consolidated undrained triaxial compression shear tests, were performed on reconstituted marine clays with different pore fluid salinities. Based on the experimental data, the salt leaching effects on the hydro-compressive and undrained shear behaviour are studied. The key factors, which affect the change in mechanical behaviour of reconstituted marine clays induced by salt leaching, were also discussed; (3) The quanlitative relationships between the mechanical behaviour and physical parameters are discussed within the intrinsic compression and shear strength theories. Then, some simple methods are proposed for predicting the compression parameters, the unconsolidated undrained shear strength and the permeability of reconstituted marine clays; (4) Some mechanical tests were conducted on undisturbed specimens both with and without salt leaching, for investigating the salt leaching effects on mechanical behaviour of natural marine clays. Then, factors controlling the alteration in the mechanical behaviour of undisturbed soils with salt leaching, are explored with considering the influence of stress level; (5) The mechanisms controll the salt leaching effects on the mechanical behaviour of natural marine clays are discussed, by comparing and analyzing the changes in the mechanical behaviour of undisturbed and remoulded specimens caused by salt leaching. It has been found that the deterioration in the mechanical behaviour caused by salt leaching, is mainly attributed to the alteration in the physical properties. Then, a quantitative method is given to evaluate the salt leaching effect on the mechancial behaviour.
学术讨论
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东南大学 2014年9月14日 岩土工程馆二楼报告厅 宋苗苗 盐分浸析对海相沉积土物理力学性状影响试验研究安排
东南大学 2015年12月19日 岩土工程馆二楼报告厅 宋苗苗 盐分浸析对天然沉积黏土压缩性状影响试验研究
东南大学 2016年6月6日 岩土工程馆二楼报告厅 宋苗苗 盐分浸析对土体物理力学影响相关论文撰写
     
学术会议
会议名称时间地点本人报告本人报告题目
Geo-Chicago 2016: Sustaninability, Energy, and the Geoenvironment 2016年8月15日 美国芝加哥 Experimental investigation of the effect of salt leaching on the compression behaviour of reconstituted Wenzhou clay
第三届全国环境土工学术研讨会 2016年11月12日 江苏省南京市 盐分浸析对土体物理性质的影响:和流黏土的比较
     
代表作
论文名称
盐分浸析对我国海相沉积土物理性质的影响
Pore fluid salinity effects on physicochemical-compressive behaviour of reconstituted marine clays
Experimental Investigation of the Effect of Salt Leaching on the Compression Behavior of Reconstitut
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
朱伟 正高 教授 博导 河海大学
李晓昭 正高 教授 博导 南京大学
钱振东 正高 教授 博导 东南大学
邓永锋 正高 教授 博导 东南大学
曾玲玲 正高 教授 博导 福州大学
      
答辩秘书信息
姓名职称工作单位备注
丁建文 副高 副教授 东南大学