基于地基土压缩理论的桩筏基础外挑筏板内力简化计算方法及应用

Simplified Calculation Method and Application of Internal Force of Pile-raft Foundation Overhanging Raft based on Foundation Soil Compression Theory

针对桩筏基础外挑筏板内力计算复杂的现状,提出一种简化计算方法。该方法基于地基土压缩理论,在一定的基本假定条件下,利用地基土沉降与筏板底部受力之间存在的关系,建立筏板底部均布荷载系数计算公式;结合筏板顶部均布荷载系数计算,在荷载叠加原理下得到筏板等效均布荷载系数;进而利用结构力学的基本公式,建立外挑筏板内力与筏板以下各层土体压缩量之和的简化计算公式。将该简化计算方法应用于某桩筏基础外挑筏板,验算在规范允许的最大沉降量下外挑筏板的受力状态,并判断其配筋是否满足要求。结果表明,该简化计算方法简单实用,可为类似工程提供参考。

Aiming at the current situation that the calculation of the internal force of the piled raft foundation is complicated,a simplified calculation method is proposed.This method is based on the foundation soil compression theory,and under certain basic assumptions,using the relationship between the foundation soil settlement and the force at the bottom of the raft,the formula for calculating the uniform load coefficient at the bottom of the raft is established.Combined with the calculation of the uniformly distributed load coefficient at the top of the raft,the equivalent uniformly distributed load coefficient of the raft is obtained under the principle of load superposition.Then,using the basic formula of structural mechanics,a simplified calculation formula of the sum of the internal force of the raft and the compression of the soil layers below the raft is established.The simplified calculation method is applied to a piled raft foundation with an overhanging raft to check the stress state of the overhanging raft under the maximum settlement allowed by the code,and determine whether its reinforcement meets the requirements.The results show that the simplified calculation method is simple and practical,and can provide reference for similar projects.