为了对非饱和土平地地基的极限承载力进行理论计算和定性分析,对非饱和土条形地基的承载力进行了计算,将基质吸力和有效应力系数引入平衡方程,构建含有非饱和参数的滑移线方程,并采用滑移线法将得到的非饱和土滑移线方程改为差分方程进行求解。综合讨论了黏聚力、内摩擦角、地下水位及垂直不饱和流速对非饱和土条形地基承载力的影响,并计算了不同情况下的非饱和土条形地基承载力,得出非饱和土平地地基的极限承载力和平均承载力均要大于饱和土地基。计算所使用的基质吸力不是一个定值,更符合实际情况,研究成果为非饱和土地基承载力计算提供了一种参考。
Abstract
To accomplish theoretical calculation and qualitative analysis on the ultimate bearing capacity of the flat foundation of unsaturated soil, the bearing capacity of strip foundation in unsaturated soil are calculated. The matric suction and effective stress coefficient are introduced into the equilibrium equation to obtain the slip line equation containing unsaturated parameters, which is further altered into difference equation using the slip line method. The effects of cohesion, internal friction angle, groundwater level and vertical unsaturated velocity on the bearing capacity of strip foundation of unsaturated soil are discussed comprehensively, and the bearing capacity of strip foundation of unsaturated soil under different conditions is calculated. Results show that the ultimate bearing capacity and the average bearing capacity of unsaturated soil flat foundation are greater than those of saturated soil foundation. The matric suction used in the calculation is not a fixed value, but is more in line with the actual situation, hence providing a reference for the calculation of bearing capacity of unsaturated soil foundation.
关键词
非饱和土 /
条形地基 /
地基承载力 /
滑移线法 /
差分方程
Key words
unsaturated soil /
strip foundation /
bearing capacity /
slip line /
difference equation
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 陈祖煜.土力学经典问题的极限分析上、下限解[J].岩土工程学报,2002,24(1):1-11.
[2] 陈 震.散体极限平衡理论基础[M].北京:水利电力出版社,1987.
[3] SOKOLOVSKII V V. Statics of Soil Media[M]. London: Pergamon Press,1965.
[4] TERZAGHI K, PECK R B. Soil Mechanics in Engineering Practice[M]. New York: John Wiley and Sons,1967: 258-262.
[5] 肖大平,朱维一,陈 环.滑移线法求解极限承载力问题的一些进展[J].岩土工程学报,1998,20(4):28-32.
[6] 张美燕,黄传志.特征线法的极限荷载与地基极限承载力[J].中国港湾建设,2005(3):8-12.
[7] 徐德馨,周玉琴.傅旭东.条形浅基础极限承载力的滑移线解[J].中国农村水利水电,2006(2):86-88.
[8] BISHOP A W, BLIGHT G E . Some Aspects of Effective Stress in Saturated and Partly Saturated Soils[J]. Géotechnique, 1963, 13(3):177-197.
[9] VANAPALLI S K, FREDLUND D G, PUFAHL D G, et al. Model for the Prediction of Shear Strength with Respect to Soil Suction[J]. Canadian Geotechnical Journal, 1996, 33(3):379-392.
[10]LU N. Profiles of Steady-state Suction Stress in Unsatu rated Soils[J]. Journal of Geotechnical & Geoenvironmental Engineering, 2004, 130(10):1063-1076.
[11]龚晓南,史东美.滑移线场数值解[M].北京:中国建筑工业出版社,2000:193-214.
[12]VAN GENUCHTEN M T. A Closed-form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils[J]. Soil Science Society of America Journal, 1980, 44(5): 892-898.
PDF(3444 KB)
