侧限条件下饱和砂土的液化机理研究  

Study on liquefaction mechanism of saturated sand under confined condition

作　　者：许成顺[1,2] 刘海强[1] 杜修力[1,2] 尹占巧[1] 

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]首都世界城市顺畅交通北京市协同创新中心,北京100124

出　　处：《土木工程学报》2014年第4期92-98,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(51278015);北京市教委重点项目(KZ201210005010);国家973计划项目课题(2011CB013600)

摘　　要：利用土工动态真三轴仪进行侧限条件下饱和砂土的液化试验研究。通过对应力时程曲线及有效应力路径的分析发现,侧限条件下循环荷载试验中饱和砂土达到初始液化后孔隙水压力和围压随轴向动荷载同步等值变化,广义剪应力和有效平均主应力始终保持在液化应力水平,基于以上现象提出"持续液化"的概念,与常规试验中的"瞬时液化"进行比较发现,常规试验中影响土体剪胀性的因素,如密度、固结比、粒径,并不会影响侧限条件下循环荷载试验中"持续液化"的发生。In this work, experimental studies on liquefaction of saturated sand were carried out under confined condition by using geotechnical dynamic true triaxial apparatus. Based on the analysis of stress time-history curves and effective stress path, it is found that in cyclic loading test under confined condition, the pore water pressure and confining pressure may change synchronously and equivalently with axial dynamic load, and that the generalized shear stress and mean effective principal stress always remain at liquefaction stress level after the liquefaction is initialized. Based on the above phenomena, the concept of ＂continued liquefaction＂ is proposed. Compared with ＂ instant liquefaction＂ in conventional test, it is found that the factors affecting the dilatancy of saturated sand in conventional test such as consolidation stress ratio, density and particle size would not influence the occurrence of ＂continued liquefaction＂ in cyclic loading test under confined condition.

关 键 词：持续液化 瞬时液化 侧限条件 

分 类 号：P642.26[天文地球—工程地质学] TU435[天文地球—地质矿产勘探]