不同桩头约束下水平受荷单桩简化计算方法

桩头转动约束对水平加载单桩的响应有显著影响。转动刚度K和桩头约束度λ是常用的桩头转动约束表征量。该文采用p-y曲线法分析了砂土中水平受荷竖直弹性长桩响应随K和λ的变化规律,提出了桩头位移和土面下桩身最大弯矩随λ变化的经验公式。基于上述经验公式和特征荷载的归一化表达式,提出了给定K或λ情况下计算桩头位、桩头弯矩、土面下桩身最大弯矩及其埋深位置的整套简化计算方法。该简化方法实现了考虑桩头转动约束单桩非线性响应的手工计算。该方法与p-y曲线法对比验证了该方法的准确性。

SIMPLIFIED METHOD OF LATERALLY LOADED SINGLE PILES WITH PARTIAL PILE HEAD FIXITY

The Rotational restraint at the top of a pile has an important influence on its behavior under lateral loading. Rotational stiffness, K, and percent fixity, λ, are two parameters commonly used to quantify the pile-head rotational restraint. A p-y method was employed to analyze the responses of a straight flexible pile with partial pile head fixity in sand. It is found that the pile-head displacement and the maximum bending moment below ground approximately linearly vary with λ. Based on the observation, a simple method derived from the CLM method is proposed to calculate the pile-head displacement, the pile-head bending moment, the maximum bending moment underground, and the embedded depth of the maximum bending moment underground of a single pile subjected to lateral loading. The proposed method provides a way to calculate the nonlinear response of laterally loaded single piles with partial pile head fixity by hands. The good accuracy of the proposed method was proved by comparing the results predicted by the method with those by the p-y method.