土体侧移作用下桩基侧向土压力的群桩效应  

The Group Effect on the Lateral Earth Pressure of Piles Subjected to Lateral Soil Movement

作　　者：李琳 马荣[1,2] 李敬梅 柳士明 杨敏 LI Lin;MA Rong;LI Jingmei;LIU Shiming;YANG Min(School of Civil Engineering,Tianjin Chengjian University,Tianjin 300384,China;Tianjin Key Laboratory of Soft Soil Characteristics and Engineering Environment,Tianjin 300384,China;China Railway Design Corporation,Tianjin 300383,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]天津城建大学土木工程学院,天津300384 [2]天津市软土特性与工程环境重点实验室,天津300384 [3]中国铁路设计集团有限公司,天津300308 [4]同济大学地下建筑与工程系,上海200092

出　　处：《防灾减灾工程学报》2022年第3期561-570,共10页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(41172233);天津市自然科学基金项目(16JCQNJC07700);天津市自然科学基金项目(13JCZDJC35500)资助。

摘　　要：当前工程建设中受土体侧移作用影响的桩基问题越来越突出,桩侧土压力是桩⁃土相互作用研究中的重要问题,并且受群桩效应影响很大,运用岩土数值计算程序FLAC3D,针对粘土饱和不排水情况进行了平面应变数值模拟研究,土体采用摩尔⁃库伦理想弹塑性本构关系,桩基采用线弹性本构关系,桩⁃土之间建立接触面。研究结果表明,桩周粘结力对桩侧极限土压力有明显影响,达到桩侧极限土压力所需要的桩土相对位移随E/Cu的增大而减小。单排桩时,随着桩间距增大桩土荷载分担比降低,桩侧极限土压力值增大,达到极限土压力时所需要的桩土相对位移增大。双排桩时,当桩间距大约为2D时加筋和遮拦效应影响范围比较小,然后随桩间距增大加筋和遮拦效应影响范围增大,而排间距的增大会使遮拦和加筋作用降低,当排间距大于6D后遮拦和加筋效应基本消失,桩间距和排间距的增大都使达到桩侧极限土压力所需要的桩土相对位移量增大,并将计算结果与先前学者试验结果进行了对比与分析,具有较好的一致性并有所发展。At present,the problems of piles subjected to the lateral soil movement become more and more serious in engineering construction.In this aspect,the lateral earth pressure acting on the pile shafts is an important problem for piles-soil interaction studies and is greatly affected by the pile group effect.The plane-strain numerical simulation is carried out for the lateral earth pressure of the passive pile group under undrained conditions in soft clay using the explicit finite difference program FLAC3D.The Mohr-Columb elastic-plastic constitutive model was employed to model the non-linear stressstrain soil behaviour.Piles were assumed to have linear elastic behaviour,and the interface model in⁃corporated in FLAC3D code was used to simulate the pile-soil contact.The results given by the numeri⁃cal analysis indicate that the adhesions between the pile and soil had an obvious influence on the lateral limiting soil pressure.The magnitude of relative displacement to mobilize the limiting soil pressure de⁃creased with the E/Cu increasing.With the pile spacing increasing for one row piles,the bearing ratio of piles decreased,and the lateral limiting pressure and the magnitude of relative displacement to reach the lateral limiting pressure all increased.For two row piles,when the pile spacing in a row lied in about 2D,the shadowing effects and reinforcing effect were obvious.With the pile spacing increasing in a row,the shadowing effects and reinforcing effect became obvious in larger row spacing.With the increase of row spacing,the shadowing effects and reinforcing effects decreased.The shadowing ef⁃fects and reinforcing effect in the two pile rows disappeared when the rows spacing increased to 6~8D.In addition,the increase of the pile spacing and row spacing make the magnitude of relative dis⁃placement mobilize the limiting earth pressure increase.The results of the numerical investigation were in reasonable agreement with the experiment result and other published solutions and developed here.

关 键 词：土体侧移 群桩效应 桩侧极限土压力 土拱效应 遮拦效应 

分 类 号：TU473.1[建筑科学—结构工程]