循环荷载作用下饱和粘土中的有效应力原理的实验研究  

Experimental Study of the Effective Stress Principle in Saturated Clay under Cyclic Loading

作　　者：李飒[1] 李忠刚 周扬锐 黄建川[1] 

机构地区：[1]天津大学建工学院,天津300072 [2]北京中船重工船舶设计研究中心,北京100086 [3]中海油服,天津300021

出　　处：《实验力学》2010年第3期279-285,共7页Journal of Experimental Mechanics

基　　金：国家高技术研究发展计划(863);项目编号:2006AA09A110;留学回国启动基金资助项目

摘　　要：有效应力原理是土力学中的经典理论,在土动力学中,有效应力原理的应用基本上是沿用土静力学中的方法,即通过建立合理的孔压模式,利用有效应力原理对土体的破坏进行分析。但是通过动三轴试验发现,在动三轴不固结不排水试验中,整个试验过程中孔压不发生变化,土体强度却发生了明显的衰减。这种现象利用有效应力原理无法得到合理的解释。针对这种现象,本文建议引入损伤变量D,作为反映土体结构变化的参数,对有效应力原理进行修正。经过修正后的有效应力原理反映了在循环荷载作用下,循环扰动造成的结构损伤对有效应力的影响,可以合理地解释动力作用下土体中孔压和有效应力相互转换,以及土体强度衰减的原因。The principle of effective stress is the classical theory in soil mechanics. In soil dynamics, the effective stress theory is also used without any modification. But according to the results of unconsolidated undrained cyclic triaxial tests, it is found that the soil strength decreases obviously along with the cyclic number while the pore water pressure does not vary during the tests. Effective stress principle can’t explain this phenomenon clearly. Aim at this problem, a damage factor D is introduced in this paper to express the influence of soil structure change on the soil effective stress. Based on this factor, the effective stress principle is modified. The modified effective stress principle can express not only the relationship between effective stress and pore water pressure but also the damage influence of soil structure on the effective stress, and can also explain why soil strength decreases under cyclic loading.

关 键 词：饱和粘土 循环荷载 动三轴试验 损伤变量 有效应力原理 

分 类 号：TU435[建筑科学—岩土工程]