基于结构受力状态理论的群桩基础承载力研究

Research on the Bearing Capacity of Group Pile Foundation Based on the Theory of Structural Stress State

目的 将结构受力状态理论应用于群桩基础的承载力判定,推广计算群桩基础安全容度和降低材料浪费的方法,为群桩设计提供有力依据。方法 依托沈阳航空航天大学图书馆现场静载试验,通过ABAQUS有限元模拟软件建立群桩基础模型,应用结构受力状态理论分析实测数据与模拟数据,精确判定群桩基础工作过程中的弹塑性分支荷载与失效荷载,并与当前规范理论获取的荷载判定结果进行对比。结果 在考虑群桩效应等不利因素的前提下,所判定的群桩承载力在保证安全的同时,相较于以控制沉降为40 mm方式得到的群桩基础设计荷载提高了21.6%,失效荷载比极限荷载大770 kN。结论 弹塑性分支荷载可以直接作为群桩基础的设计荷载,从极限荷载至失效荷载这一区间经证明群桩结构可以正常工作,可作为群桩基础的安全裕度使用,为研究群桩基础承载力提供了新方法。

In order to study the application of the theory of structural stress state to the determination of bearing capacity of group pile foundation,to popularize the method of calculating the safety capacity of group pile foundation,to reduce the waste of materials,and to provide a strong basis for the design of group piles.Based on the static load test results in the library of Shenyang Aerospace University,the group pile foundation model was established by ABAQUS finite element simulation software,and the structural state of force theory was applied to analyze the measured and simulated data to accurately determine the elastic-plastic branch load and failure load during the working of group pile foundation,and to compare with the load determination results obtained from the current code theory.It is found that under the premise of considering the group pile effect and other unfavorable factors,the determined bearing capacity of the group pile is 21.6%higher than the design load of the group pile foundation obtained by controlling the settlement of 40 mm,and the failure load is 770 kN more than the ultimate load in terms of load.The elastic-plastic branch load can be directly used as the design load of group pile foundation,and the interval from ultimate load to failure load is proved that the group pile structure can work normally,and it can be used as the safety margin of the group pile foundation,which provides a new method for the study of the bearing capacity of group pile foundation.