基于接触模型的竖向荷载桩土沉降及承载力分析

Contact Model Analysis of Settlement and Bearing of Pile-Soil System Under Vertical Loads

利用ANSYS有限元分析软件,基于桩土间接触模型,采用Drucker-Prager准则建立三维有限元模型,对3种土体中桩在竖向荷载作用下的沉降及承载力进行分析.分别讨论相同桩径不同桩长、不同桩径相同桩长时的桩端沉降及承载力变化,并将数值模拟结果与理论计算结果进行比较.结果显示,相同桩径不同桩长在不同土体中的承载力变化不明显,但随桩长增加沉降量明显下降,砂土中沉降最小,黄土次之,黏土最小.不同桩径相同桩长时,桩径的变化引起的沉降变化明显而承载力变化不大.当桩长与桩径的比值在15~30之间时,桩的承载力效果较好,且沉降量适中.数值计算结果与理论值吻合,验证了计算模型的准确性和可行性,为进一步的模型试验提供科学指导.

Using ANSYS finite element analysis software and pile-soil contact model,this paper develops a 3Dfinite element model based on the Drucker-Prager criterion to analyze the bearing and settlement of piles in three different soils under vertical loads.The settlement and bearing capacity of the same pile diameter with different lengths and different pile diameters with same pile length are discussed,and the numerical results are compared with theoretical calculations.The results show that in different soils,the bearing capacity does not change significantly in the same pile diameter with different lengths,however,the settlement amount decreases significantly with the smallest settlement in sand,then in loess,and the largest in clay.In the same length with different diameter piles,the settlement changes largely due to different diameters,while bearing has little change.It shows that bearing is better and settlement is moderate when the pile ratio of diameter and pile length is between 15 and 30,and the theoretical results correlate well with the experimental ones.It verifies the accuracy and feasibility of the calculation model,which can provide a scientific guidance for further trials.