桩、土、刚性承台相互作用下桩基内力计算新方法

针对港口工程中广泛使用的桩基础在波浪力及荷载作用下与高桩刚性承台和土共同工作的问题,提出较为有效、合理的计算方法.首先以杆系有限元方法为基础,将承台模拟成一根竖直刚性梁,将桩基模拟成线弹性梁,以承台与桩基相连的节点作为主节点,桩基与承台相连的节点为从节点,推导出了刚性承台和桩基的单元刚度方程;其次,桩基与土的相互作用按弹性桩的线性地基反力假设法中的m法计算,推导出了桩土相互作用下桩基单元刚度方程;最后,将波浪力等效成相应桩基单元上的节点荷载,并编写相应的有限元程序(FEPPRC).算例表明:所提出的在波浪力及其他荷载共同作用下考虑桩土相互作用的刚性承台桩基内力计算新方法是可靠的.

The New Computing Method of Internal Force of Piles Under the Interaction of Piles,Soils and Rigid Cap

An efficient computing method is brought forward to resolve the interaction work of piles, soils and rigid cap. Firstly, the computing method is based on FEM of bar with the rigid cap as an erect rigidity bar and a pile as a linear elastic beam. Then, the node of the rigid cap connected with a pile is act as main node,while the node of pile connected with rigid cap is act as subordinate node. The stiffness equation of rigid cap and pile groups is deduced from the above supposition. Secondly, with using the design of pile foundation by M-method, the stiffness equation of pile under the interaction of piles and soils is derived.Finally, wave force is equivalent to the panel load on the corresponding element of piles. Based on the stiffness equations, the finite element program is obtained through the language of FORTRAN. Examples show that this computing method is reliable and reasonable.