基于沉降控制的刚性桩复合地基设计方法及应用

DESIGN METHOD FOR RIGID PILE COMPOSITE FOUNDATION BASED ON SETTLEMENT CONTROL AND ITS APPLICATION

Some problems of rigid pile composite foundation design according to current codes have been analyzed. After investigating the function of cushion in rigid pile composite foundation and the influence rules of cushion thickness and stiffness of soil on pile-soil stress ratio，the tangent modulus method proposed by YANG Guanghua is used to study the design method according to settlement control. The design method is presented as follows. Firstly，supposing that pile and soil are independent systems，the nonlinear p-s curves(where p is stress，s is settlement) of pile and soil are calculated，respectively. Then，according to the deformation compatibility principle，the settlement curve of composite foundation is obtained by the above p-s curves. Finally，by controlling settlement and adjusting cushion thickness，loads on piles and soil are optimized，which makes the design of rigid pile composite foundation reach the best state. A practical project design is optimized by this method. The calculation value is very close to the measured settlement，which proves the rationality of this design method. This method better considers pile-soil interaction；and its parameter determination is relatively simple and reliable，so as to give a new idea in rigid pile composite foundation design.