成层土中单桩受力性状简化算法

SIMPLIFIED ANALYTICAL METHOD FOR RESPONSE PREDICTION OF SINGLE PILE EMBEDED INTO LAYERED SOILS

提出一种成层土中单桩非线性受力性状的简化分析方法。单桩受力性状分析时采用侧阻软化模型模拟桩侧阻力和桩身位移间的关系,桩端位移–荷载关系采用双曲线模型。在上述2种模型的基础上,利用迭代算法得到单桩沉降。利用该算法得到的结果与现场实测数据对比分析表明其在单桩受力性状计算方面是合理可行的。算例分析表明,同一荷载水平下,单桩桩顶沉降随侧阻破坏比的增大而减小,随端阻破坏比的增加而增大。采用提出侧阻软化模型分析单桩受力性状时,侧阻完全发挥时对应的桩土相对位移对单桩受力性状的影响较小。

A simplified approach for nonlinear analysis of response of a single pile embedded in layered soils is presented. Two models are adopted in the proposed approach. One model uses a softening nonlinear relationship to simulate the degradation behavior between unit skin friction and pile-soil relative displacement developed along the pile-soil interface, and the other model adopts a hyperbolic relationship to capture the pile end response. Based on the two proposed models, a highly effective iterative computer program is developed for the analysis of single pile response. The efficiency and accuracy of the presented method is verified by using a series of field tests. Furthermore, a parametric study shows that the settlement of the single pile decreases with increasing failure ratio of skin friction, and increases with increasing failure ratio of tip resistance. It also can be concluded that the value of pile-soil relative displacement at the ultimate skin friction has a small influence on the single pile response derived from the proposed softening model of skin friction.