摘要
本文用土骨架的新概念对膨胀土的结构进行分析。将叠片、叠聚体、聚集体、复合体统称为粘聚体,粘聚体是子土骨架。膨胀土的三种孔隙,微孔隙的水稳性最好,强度最高;小孔隙次之;大孔隙最差。在天然膨胀土中,粘聚体是胀缩变形的主体;选取小孔隙或微孔隙,有水分子的渗透压力=公共结合水膜吸引力+重力效应。设想土力学研究,第一层次为以微结构单元为基本单元的体系(总土体),第二层次为以单个土颗粒为基本单元的体系(如粘聚体、集粒、凝块等等)。与普通土不同,膨胀土的大孔隙随着土体的膨胀而变小。膨胀土内有两种渗透力,一种是半透膜效应的水分子的渗透力,一种是渗流渗透力;渗流计算指标,应该用自由水孔隙比,而不是孔隙比。有效应力及大气张力库伦抗剪强度涉及的最不利位置是大孔隙。将大雨滑坡的坡体看成一个总土骨架,滑动土块是膨胀的子土骨架,裂隙是接近溃散的子土骨架,软弱结构面是损伤的子土骨架。在石灰改性膨胀土中,粘聚体被多钙结合水膜包裹,可能还被浸入内部;相邻粘聚体的多钙结合水膜包皮相交形成面胶结的强公共结合水膜,加密后高强且无胀缩性。
In this paper,a new concept of soil skeleton is used to analyze the structure of expansive soil. The lamination, the fold polymers, aggregation and complex are collectively referred to as cohesive polymers;the cohesive polymers are a subsoil skeleton. For the three kinds of pores of expansive soil ,micropores have the best water stability and the highest strength, small pores are next,and macro-pores are the worst. In natural expansive soil, the cohesive polymers is the main part of expansion and contraction deformation; if pick a small pore or a micro pore, osmotic pressure of water molecules = attraction of public water membranes ＋ gravity effect. Suppose that soil mechanics studies, the frst level is the system with microstructure unit as the basic unit （total soil body）, and the second level is the system with single soil particles as the basic unit （such as cohesive bodies, aggregates, agglomerates and so on）. Different from ordinary soil, the big pore of expansive soil decreases with the expansion of soil. There are two kinds of osmotic forces in the expansive soil, one is the osmotic force of water molecules with semi-permeable membrane effect, the other is the seepage osmotic force. The calculation index of seepage fow should use the free water porosity ratio instead of the porosity ratio. The most unfavorable position involved in effective stress and atmospheric tension coulomb shear strength is macro-porosity. If the slope body of a heavy rain landslide is regarded as a total soil skeleton, then the sliding soil block is the expanded subsoil skeleton, the crack is the subsoil skeleton close to collapse, and the weak structural surface is the damaged subsoil skeleton. In the lime modifed expansive soil, the co-hesive polymers was encased by the water flm with the multi-calcium, and may be immersed in it; the strong and public bind-ing water flm formed by the intersections of the multi-calcium bound water flm foreskin of the adjacent cohesive polymers, In addition, the strength of cohesive polymers and total soil skeleton was empower them high strength and no swelling and shrinkage after encryption.
作者
蒙理明
刘晓玲
Meng Liming;Liu Xiaoling(Haikou University of Economics,Haikou.443002,China)
出处
《建设科技》
2018年第21期30-37,共8页
Construction Science and Technology
