桩承式加筋路堤三角形布桩下桩土应力分析  

Pile-soil stress analysis of geogrid-reinforced pile-supported embankments with piles arranged in triangle

作　　者：刘洪凯[1,2] 夏唐代[1,2] 

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058

出　　处：《中南大学学报（自然科学版）》2014年第11期3957-3963,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51078330)~~

摘　　要：针对桩承式加筋路堤中三角形布桩场地,将方形桩帽等效为六边形进行分析计算。假设土拱是由3根等距离桩内接形成的半球环,边界条件与Hewleet的假定有所不同,以此为出发点进行土拱效应的分析推导;假设拉膜区域同样由3根等距离桩内接形成,在上覆填土的重力作用下,加筋垫层产生的弯沉沿径向呈抛物线状,每个桩帽连接桩周的6个拉膜区域,并以此分析桩帽承担的加筋材料的拉力。最后,将土拱效应和拉膜效应的作用统一考虑,提出桩体荷载分担比的计算方法,与一工程实例进行对比验证本文提出方法的正确性,并对相关参数进行分析。研究结果表明:在同等条件下,路堤桩体荷载分担比随路堤填料的朗肯被动土压力系数Kp和桩帽宽度与桩间距之比δ的增大而增大,考虑"土拱效应"和"拉膜效应"共同作用下的桩土应力的差异显著大于仅考虑"土拱效应"的桩土应力差异。When analyzing the pile-soil stress of geogrid-reinforced pile-supported embankments with piles arranged in triangle, square pile caps were turned into regular hexagons. And soil arch was assumed as part of spherical surface between three equidistant piles to study its＇ effect, which is different from Hewlett＇s theory. Then the tensioned membrane area of each pile was divided into six parts, and the tension of the reinforced material caused by the gravity of the overlying fill was calculated according to the parabolic settlement of the reinforced cushion. After that, both the soil arching effect and the tensioned membrane effect were considered to propose a new method to calculate the pile efficacy.Finally, a projects case was used to verify the method＇s correctness, and the influence of each parameter was discussed.The results show that coefficient of passive earth pressure（Kp） of the pile efficacy increases with the increase of the ratio of pile cap dimension to pile spacing δ, and the pile efficacy that considers soil arching effect is much smaller than the one that considers either effect.

关 键 词：桩承式加筋路堤 桩体荷载分担比 土拱效应 拉膜效应 三角形布桩 

分 类 号：TU472[建筑科学—结构工程]