用土力学的新概念解读和修正经典饱和土力学

蒙理明

(海口市城市规划设计研究院，海口 570105)

摘要：论述了应该用有效应力的新概念代替经典有效应力原理。总应力压缩模量与渗流水等效压缩模量的曲线相似；有效应力压缩模量起加劲作用，而不是起决定性作用。土的压缩变形计算中应用有效应力原理是错误的。对于起始水力坡降，引入饱和粘性土的自由水压力衰减概念。在饱和粘性土中，自由水通道率折减不大，相对自由水压力通过一定厚度后衰减为零。所以，新概念土力学的算法接近我国规范：“对粘性土宜按水土合算计算”。还解读了地下室浮力折减、流沙陷阱等等。

关键词：有效应力的新概念；土的压缩变形；饱和粘性土；起始水力坡降；自由水压力衰减

doi:10.3963/j.issn.1674-6066.2015.03.026

Abstract:This paper discusses that it should use the new concept of effective stress instead of classical effective stress principle. Curves of total stress compression modulus and the seepage water equivalent compression modulus are similar；effective stress compression modulus is stiffening effect, rather than a decisive role. Using the principle of effective stress is wrong in the soil compression deformation calculation . For the initial hydraulic gradient,this paper introduced a concept of the free water pressure attenuation of saturated cohesive soil. In saturated cohesive soil, free water channel rate reduction is not large, relatively free water pressure attenuation is zero through certain thickness. So the new concept of soil mechanics algorithm is close to our specification:"cohesive soil should be calculated on soil and water economical". Also the basement uplift reduction, shifting sand traps and so on are introduced.

收稿日期：2015-04-19.

作者简介：蒙理明(1955-),教授级高工.E-mail:66229258mlm@163.com

Interpretation and Revision of Classic Saturated Soil Mechanics

with New Concept of Soil Mechanics

MENGLi-ming

(Urban Planning & Design Institute of Haikou,Haikou 570105,China)

Key words:the new concept of effective stress;soil compression deformation;saturated cohesive soil;initial hydraulic gradient;free water pressure attenuation

太沙基1923年提出了饱和土中的有效应力原理。九十二年来，土力学的许多重大进展都是与有效应力原理的推广和应用相联系的。所以，太沙基的有效应力原理是经典饱和土力学的基石。尽管如此，经典饱和土力学还是存在疑惑。如经典有效应力原理在饱和粘性土中的适用性、土压力的水土分算和水土合算、地下室浮力折减、流沙陷阱等等。

见文献[1]的结论，由文献[2-11]总结，初步得到非饱和土有效应力的大气张力公式与新概念土力学的构架，其中有：

1)应该用有效应力的新概念代替经典有效应力原理，即有效应力是土体中提供抗剪强度的点的集合所对应的应力。……