摘要
微型桩因灵活高效的抗滑性能得到广泛应用,但桩顶连系结构的作用机理并不清楚.利用有限差分(FLAC3D)数值模拟方法,揭示桩顶连系结构对微型群桩应力应变特征的影响.结果表明:(1)同级侧向荷载作用下,连系梁使3#桩位移下降12.9%,8#桩位移下降14.2%.表明连系梁可以有效延缓边坡变形,且可以对第二排桩有更好的位移限制作用;(2)两组工况的临界与极限荷载相同,表明桩顶连系梁无法显著提高微型群桩的抗滑能力;(3)同级侧向荷载作用下,两组工况的桩身应力均在滑裂面上下呈三角形分布,仅在桩顶有一定差别存在.连系梁使滑坡推力分担比由0.58∶0.42提高到0.53∶0.47.相对于独立式群桩,连系式群桩滑坡推力分担更为平均.(4)同级侧向荷载作用下,两组工况的桩身弯矩均呈现倒“S”形.连系梁可以限制桩顶变形,使第一排微型桩桩顶后侧受拉,随着深度增加,连系梁影响降低.在连系梁的作用下,两排桩几乎同时失去抗弯作用.
Micro-pile has been widely used due to its flexible and efficiency,but the mechanism of the pile-top connection structure is not clear.The finite difference(FLAC3D)numerical simulation method is used to reveal the influence of the pile top connection structure on the stress-strain characteristics of the micro-pile group.The main conclusions are as follows:①Under the same level of lateral load,the connecting beam reduces the displacement of the 3#pile by 12.9%,and the displacement of the 8#pile by 14.2%.It shows that the connecting beam can effectively delay the slope deformation,and can have a better displacement limiting effect on the second row of piles.②There is no change in the critical load and ultimate load of the two models,indicating that the connection beam does not improve the anti-sliding capacity of the micro-pile group.③Under the same level of lateral load,the pile body stress of the two groups is distributed in a triangle shape on the top and bottom of the slip surface,and there is only a certain difference at the top of the pile.The connection beam improves the landslide thrust sharing ratio from 0.58∶0.42 to 0.53∶0.47.Compared with the independent pile group,the landslide thrust sharing of the connected pile group is more even.④Under the same level of lateral load,the bending moment of the pile body in the two working conditions is an inverted“S”shape.The connecting beam can limit the deformation of the pile top,so that the rear side of the top of the first row of micro piles is pulled,and the influence of the tie beam decreases as the depth increases.Under the action of the tie beam,the two rows of piles lose their bending resistance almost at the same time.
作者
唐斌
张常亮
赵猛
司佳鹏
李同录
TANG Bin;ZHANG Changliang;ZHAO Meng;SI Jiapeng;LI Tonglu(Department of Geological Engineering,College of Geological Engineering and Surveying,Chang’an University,Xi’an 710054,China;Field Observation and Research Station of Water Cycle and Geological Environment of the Ministry of Education of the Loess Plateau,Qingyang 745399,Gansu China)
出处
《河南科学》
2022年第6期964-972,共9页
Henan Science
基金
国家重点研发计划(2017YFC1501302)
长安大学中央高校基本科研业务费专项资金(300102260204)
陕西省自然科学基础研究计划(2022JM-167)。
关键词
独立式微型群桩
连系式微型群桩
桩顶连系结构
三维数值分析
independent micro-pile group
connected micro-pile group
pile top connection structure
threedimensional numerical analysis
