基于OpenSees的桩-土-桥墩相互作用非线性数值分析模型

Nonlinear analysis model for pile-soil-pier interaction based on OpenSees platform

基于OpenSees数值分析平台,建立了群桩-土-桥墩非线性数值分析模型。模型中桩-土水平向相互作用和桩-土竖向相互作用、桩底-土竖向相互作用分别通过p-y、t-z与q-z零长度弹簧单元模拟。模型中同时考虑了群桩效应与纵筋在墩底的应变渗透和粘结滑移的影响。结合群桩基础拟静力试验结果,对数值模型的准确性进行了验证,在此基础上对土体参数特性对桩基滞回性能的影响规律进行了分析。结果表明:所建立的数值分析模型可对群桩基础滞回曲线和骨架曲线进行较为准确的模拟分析,验证了模型的可靠性。反复荷载作用下,前桩处土体的反应明显大于中桩处;土体由软黏土变为硬黏土时,墩顶侧向承载力与刚度显著增加,但土体的非线性反应减弱。

The nonlinear analysis model for group piles-soil-bridge pier interaction was built based on the OpenSees platform.The pile-soil horizontal interaction,pile-soil vertical interaction and pile tip-soil vertical interaction was simulated by p-y,t-z and q-z zero-length spring elements,respectively.Also,pile group effect and longitudinal bar strain penetration and bond-slip effect at the bottom of the bridge pier was considered.The accuracy of the model was verified by the result of the quasi-static test on pile group bridge foundation.At last,the influence of the soil parameters on the hysteretic behavior of the foundation was studied.The results are as follows.The model can simulate the hysteretic and skeleton curves of the pile group foundation well and the reliability of the model has been confirmed.The response of the soil surrounding the front pile is obviously greater than that surrounding the middle pile under cyclic loading.When the soft clay soil surrounding the pile is changed to be stiff clay soil,the lateral bearing capacity and stiffness of the pier top will be increased significantly,but the nonlinear response of the soil will be decreased.