桩径和扩径比对大直径扩底灌注桩工程特性影响分析

以中山西环高速公路为工程背景,采用有限元软件PLAXIS 3D进行了桩径和扩径比对扩底桩工程特性的影响数值模拟。分析结果表明:当扩径比(D/d)为1.5～2.5、桩径为1.2～1.6 m时,桩体尺寸对其竖向极限承载力影响明显,随着桩径或扩径比的增加,竖向承载力提升幅度较大;当扩径比为1.5～2.0、桩径为1.2～1.6 m时,桩体尺寸对扩底桩抗拔承载性能影响较大;当扩径比为1.0～2.0、桩径为1.0～1.4 m时,扩底桩桩顶沉降变化较快。通过现场静载试验对有限元计算结果进行验证,两者吻合较好。

Impact of Pile Diameter and Expanding Diameter Ratio on Engineering Characteristics of Belled Pile

Taking the Zhongshan West Ring Expressway as the engineering background, the finite element software PLAXIS 3D was used to simulate the influence of the pile diameter and the expansion ratio on the engineering characteristics of the expanded pile. The analysis results show that when the diameter expansion ratio is D/d=1.5-2.5 and the pile diameter d=1.2-1.6m, the pile size has an obvious influence on the vertical ultimate bearing capacity. With the increase of the pile diameter or the expansion ratio, The vertical bearing capacity increases greatly; when the diameter expansion ratio is D/d=1.5-2.0 and the pile diameter d=1.2-1.6m, the pile size has a great influence on the uplift bearing capacity of the expanded pile; When D/d=1.0-2.0 and pile diameter d=1.0-1.4m, the settlement of the pile bottom of the bottomed pile changes rapidly. The finite element calculation results were verified by the on-site static load test, and the two were in good agreement.