Research On Vertical Bearing Capacity Of Statically Pressed Precast Concrete Pile In Karst District

Because of low cost,high construction speed,no noise and high quality, statically pressed precast concrete pile is widely used in construction engineering, especially in GuangDong. But because limestone is widely distributed in GuangDong, much problem may happen in the use of statically pressed precast concrete pile. However, research on bearing capacity of statically pressed precast concrete pile in karst district is small and not mature enough. So this dissertation do a deep and systemic research on it, all work is provided for the use and development of statically pressed precast concrete pile in karst distric.Based on a lot of research on bearing capacity of statically pressed precast concrete pile and stability of pile foundation in karst district, soil is regarded as linear spring to simulate the pile-soil interaction, and calculational formula of bearing capacity of statically pressed precast concrete pile is advanced by imitating the transferring- function method. Meanwhile, because precast concrete pile can strength nearby soil during construction, so stiffness coefficient of soil spring is modified in calculational formula. Lastly, calculational formula is solved by using iteration method in order to solve the problem that is caused by the unknown parameter.In this dissertation, bending failure,punching-shear failure and shear failure are considered as primary failure mode of karst roof, and corresponding calculational models are established. Especially in bending-stability analysis of karst roof, karst roof is simplified for four mechanics models according to shape and boundary condition. The bending stress of karst roof is calculated by using theory of plate and shell, and the bending stability is discussed by using Griffith strength theory.Based on above research harvest, author use Fortran95 to compile the Lunwen program, and use this program to analyze the bearing capacity of statically pressed precast concrete pile and the stability of karst roof. Result proves research harvest of this dissertation and the Lunwen program are correct and dependable.