江苏太仓浅部淤泥质土层的工程地质特征  

Engineering geological characteristics of shallow mucky soil in Taicang area,Jiangsu Provience

作　　者：张云[1] 薛禹群[1] 吴吉春[1] 施小清[1] 何佳佳[1] 

机构地区：[1]南京大学地球科学与工程学院,南京210093

出　　处：《水文地质工程地质》2010年第4期43-47,共5页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金(40772168);国家杰出青年科学基金(40725010)

摘　　要：太仓浅部广泛分布的淤泥质粉质粘土层具有高含水量、高压缩性和低渗透性,对开采浅层地下水引起的地面沉降研究有重要意义。本文通过一系列微观和宏观室内试验,查明该层土的矿物成分主要为伊利石,其次为绿泥石、高岭石,土中孔隙主要为中孔隙和小孔隙。在一定应力范围内,随固结压力增大,土中的中孔隙明显减小,渗透系数也明显减小,孔隙比与渗透系数之间有单对数线性关系,但当固结压力超过一定值后,土中以小孔隙为主,随固结压力增大,孔径分布变化不明显,渗透系数随孔隙比的变化也小得多。淤泥质粉质粘土层的变形以不可恢复的塑性变形为主,具有显著的蠕变性,在开采地下水引起的地面沉降中将会有明显的变形迟后。A layer of mucky silty clay distributes extensively at a shallow depth in Taicang area,Jiangsu Provience.This soil layer is of high moisture content,high compressibility and low permeability.It has therefore an important function in land subsidence due to the pumpage of shallow groundwater.A series of laboratory tests were performed to investigate the engineering geological properties.The test results show that the soil is predominantly of clay minerals such as illite,chlorite,and kaolinite,and illite predominates the clay minerals.The void in the soil is primarily of medium and small sizes.The volume of medium-size void and the coefficient of permeability of the soil decrease obviously with increasing pressure,and there is a nearly linear relationship between void and logarithmic coefficient of permeability.However,when the pressure is greater than a certain value,the void in the soil is primarily of small size,and the changes in distribution of void size and in coefficient of permeability are unremarkable with increasing pressure.This soft clay deforms plastically and with creep,causing the compaction to lag behind under the condition of groundwater pumpage.

关 键 词：淤泥质粉质粘土 工程地质性质 微观结构 渗透性 蠕变性 

分 类 号：P642.133[天文地球—工程地质学]