考虑土体固结的被动排桩土拱效应研究

摘要

被动桩在邻近堆载作用下会出现土拱效应,而三维情况下考虑土体固结的被动桩土拱效应鲜有研究.将衡量桩承式路堤土拱效应的桩土应力比等参数推广到被动桩土拱效应的研究中,考虑软土地基弹塑性-固结耦合及桩土相互作用,运用ABAQUS有限元软件建立被动排桩三维模型,分析了桩身不同深度处、桩侧不同堆载大小下被动桩土拱效应变化规律,并分析土体固结对被动土拱效应的影响.结果表明:桩身不同深度处土拱效应不同,且与桩身受到的侧向压力有关;邻近堆载的增大会减弱被动桩土拱效应;随着固结时间增长,土拱效应减弱,但减弱程度有限.%Soil arching effect appears in passive piles dues to surcharge action,but few researches consider the soil consolidation in soft soil under three dimensional circumstance. According to parameters for assessing soil arching effect of pile-supported embankment,the parameters for assessing soil arching effect in passive piles are discussed. Taking the elastoplastic-consolidation coupling effects into consideration,a three dimensional model of passive piles in soft soil foundation is established. Taking the pile-soil interaction into consideration ,the finite element analysis software of ABAQUS is used to study the change regularity of soil arching effect at different depth along pile and different load conditions. Also,the influences of soil consolidation on soil arching effect is analyzed. It is shown that soil arching effect is different in different parts of pile and is related to variation of ultimate soil pressures with depth. With the adjacent stacking load increasing,the soil arching effect in passive piles is weakened. As the time of soil consolidation goes on,soil arching effect will impair,though the impairment is limited.