考虑骨架压缩效应的饱和土有效应力原理  

Effective Stress Principle of Saturated Soils in Terms of Skeleton Compressibility

作　　者：曹宇春[1] 

机构地区：[1]浙江科技学院建筑工程学院,浙江杭州310023

出　　处：《施工技术》2013年第S1期7-11,共5页Construction Technology

基　　金：国家自然科学基金项目(40406019)

摘　　要：通常各向等值的孔隙水压力对饱和土的变形和抗剪强度不会产生影响,只有总应力中超过孔隙水压力的那部分有效应力发生变化才会导致土体发生变形及抗剪强度的改变。考虑土骨架的压缩效应,对饱和土的有效应力原理的研究进行了综述,给出了新的解释并推导了一维条件下的有效应力原理公式。结合实例对有效应力原理进行了验证,然后对其在饱和多孔介质材料中的适用性进行了探讨。分析表明:导致土骨架发生变形的有效应力等于总应力与孔隙水压力之差,有效应力与颗粒间的接触面积无关,有效应力区别于单位横截面面积上的平均粒间法向力和粒间实际法向应力。考虑多孔介质的骨架和固相材料的压缩性以及抗剪强度后发现:在通常的工程压力条件下,太沙基有效应力原理对于饱和土是成立的,而将太沙基有效应力原理应用于饱和混凝土和岩石则会产生较大误差。Pore water pressure with equal intensity in every direction has generally no influence on deformation and shear strength of saturated soils.Deformation and change of shear strength are exclusively due to changes in the effective stresses which are the differences between total stresses and pore water pressure.Research review of effective stress principle for saturated soils is done.New explanation is accordingly made and its equation under one-dimensional condition is derived in terms of skeleton compressibility.The principle is verified exploring practical examples and the validity of that for saturated porous materials is discussed.The analysis shows that effective stress which leads to deformation of soil skeleton is the difference of total stress and pore water pressure and effective is independent of the contact area of soil grains.Effective stress is different from intergranular forces per unit area and intergranular stresses.It has been found considering compressibility of skeleton and solid of porous materials that Terzaghi's effective stress principle can be applied to saturated soils subjected to normal engineering pressures while the principle will produce fairly remarkable errors for saturated concrete and rocks.

关 键 词：饱和土 有效应力原理 骨架压缩性 总应力 孔隙水压力 有效应力 

分 类 号：TU43[建筑科学—岩土工程]