基于饱和土总应力强度指标的非饱和土强度理论及其应用  

UNSATURATED SOIL STRENGTH THEORY BASED ON TOTAL STRESS STRENGTH INDEXES OF SATURATED SOIL AND ITS APPLICATION

作　　者：马少坤[1,2,3] 黄茂松[2,3] 范秋雁[1] 

机构地区：[1]广西大学,广西南宁530004 [2]同济大学地下建筑与工程系,上海200092 [3]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩石力学与工程学报》2009年第3期635-640,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：西部交通建设科技项目(200431822311);广西大学博士启动项目(x091006);广西大学科研基金项目(x071069)

摘　　要：实际工程中求解和测定吸力比较困难,特别在不排水条件下,吸力并非常量,从而难以确定。而饱和度相对容易确定,选择饱和度代替吸力,建立关于饱和度的非饱和土的抗剪强度公式有着重要的实用价值。提出不排水(等含水量)条件下的基于饱和土总应力强度指标的抗剪强度公式,克服了以往相关模型只适合于较小范围的缺陷,能够实现从非饱和土状态到饱和状态的平稳过渡,同时更能反映土体的工程特性;结合非饱和土的土水特征曲线试验及常含水量三轴剪切试验成果,确定适用于云南红黏土的相关拟合参数;将所得抗剪强度公式应用于地基承载力分析中,得到地基承载力随饱和度的减少接近线性增加的结论。It is very difficult to resolve or measure matric suction in engineering practice, because the matric suction is not constant especially under undrained condition. The degree of saturation is relatively easy to be measured, so the shear strength formula about saturation degree instead of suction has valuable significance in practical engineering. A new formula based on strength indexes of saturated soil is proposed, which can be used in whole engineering practice range including unsaturated soil and saturated soil. More intrinsical characteristics of engineering can be reflected. Proper parameters for Yunnan red clay in the above-mentioned formula are determined based on the results of soil-water characteristics and constant water content triaxial tests. Finally, the undrained shear strength formula is utilized to analyze the bearing capacity of foundation; and the conclusion that the bearing capacity increases with the reduction of degree of saturation linearly is drawn.

关 键 词：土力学 地基极限承载力 非饱和土 抗剪强度 刚性基础 

分 类 号：TU47[建筑科学—结构工程]