Study Of Caculating Of Piled-raft In High Buidingbined

As a kind of layout plan, pile-raft foundations are widely applied in tall buildings due to its commodious advantageous. Pile-raft foundations have advantages of pile and plate foundations. Pile and raft take the load of buildings together. It possesses good whole, high vertical capacity, small settlement of foundation and well performance of balancing differential settlements. It could bear large wind or seismic induced horizon load, and could have large capacity of resisting inclination. Therefore, study of calculating piled-raft foundation in tall buildings has great social effects and economical profits.Corrective level of calculation and analysis on foundation projects is determined by the choice of soil model and computation parameter for soil constitutive models, and there is the interaction of upper structure-piled raft-subsoil system. In this paper, we introduce in detail some kinds of views how to choose subsoil models correctly and how to determine computation parameters for subsoil models, and we analyze their system with reaction theory and establish balancing matrix equation of pile-raft interaction.As a kind of dispersed numerical value method, finite element method is of approximate methods, and is based on principle of variation. In designing and calculating plate of piled-raft foundation, thick-plate calculating theory has been applied, that is, thick-plate finite element method is mainly used when load and deformation of plate are analyzed. On research of piled foundation, elastic model, elastoplastic model and finite element method are also used; its analyzing method is elementarily similar to thick-plate finite element.When upper structure, pile-raft, subsoil system is studied, every part of this system is looked upon homogeneous discrete space. According to static equivalent principle, equivalent node loads are calculated, and load embattle is integrated with element equivalent node force and directly bearing load. In this paper the 8-nodes 6-planes solid element is applied to analyze pile-raft, max differential settlement of pile-raft is studied with or without upper-structure's interaction effects. Computation results with this condition are closer to the observation result than those without this condition.