摘要
为阐明长江口北岸海陆交互相沉积软土土性复杂、非均质特点,对其成因进行了分析,并基于孔压静力触探测试成果对软土层空间变异性进行了定量评价。结果表明:长江口历史上多次规模不同的海进海退及北岸砂坝并陆事件,长江口岸线往复移动,形成了长江口北岸全新世沉积物黏性土或薄层黏土与粉、细砂互层、多韵律沉积特征;细观上海陆交互相沉积土层黏土与粉砂相互夹杂,极不均质;与冲湖相、海相和泻湖相沉积土层剖面对比显示,海陆交互相沉积软土在宏观上沿深度方向存在典型的不连续性;软土层竖向相关距离由高到低依次为海相、泻湖相、冲湖相和海陆交互相沉积软土,证明海陆交互相沉积软土层的竖向相关距离最小、空间变异性最大。
In order to interpret the typical complex and inhomogeneous property of the interactive marine and ter- restrial deposit along the northern bank of Yangtze River estuary, the geological genesis of the Holocene interactive marine and terrestrial deposit of this area is analyzed. Based on in situ piezocone test achievements, spatial variability of the soft soil stratum is quantitatively evaluated. It is found that due to multiple transgressive and regressive events of different scales and merge of shoals with land in the history at Yangtze River estuary, the bank line moved forward and backward, the typical characteristic of interbedding between clayey soil or thin layer of clay and silty or fine sand is formed in the Holocene deposit, which has multi-sedimentary rhythms. From the microscopic view, mutual inclu- sion phenomenon of silty sand and clayey soil can be clearly observed, which proves its typical characteristic of inho- mogeneity. It is indicated through comparison with soil profiles of alluvial-lacustrine, that for marine and lagoonal de- posits, typical discontinuity and severe interbedding exist along the depth of soft soil stratum at the studied area from the macroscopic view. The vertical correlation distances of soft soil strata rank from high to low is as follows ： marine deposit, lagoonal deposit, alluvial-lacustrine deposit, and interactive marine and terrestrial deposit. It shows that the interactive marine and terrestrial deposit has the smallest vertical correlation distance and greatest spatial variability.
出处
《地下空间与工程学报》
CSCD
北大核心
2014年第1期102-108,共7页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金资助项目(41272311)
高等学校博士学科点专项科研基金资助项目(20100092120049)
江苏省交通厅资助项目(09Y33)
关键词
海陆交互相沉积土
地质成因
孔压静力触探
沉积软土
空间变异性
interactive marine and terrestrial deposit
geological genesis
piezoeone penetration test （ CPTU ）
soft clay deposit
spatial variability
