Research On Reliability Analysis And Design Of Bearing Capacity Of Composite Foundation

Composite foundation is a method of foundation treatment was used widespeead nowadays.It means in the process of foundation treatment a part of natrual foundation was strengthed,or repalced,or palced reinforced materials. The consolidate area is artificial foundation that include original mass(natrual ground soil or improved ground soil)and strengthed mass.The research of reliability started as early as 30's,which was applied in structure design about 40's and later in geotechnical engineering.Bacause of so many uncertian and unkonw factors in geotechnical engineering the application of reliability theory in resolving geotechnical engineering problem is more difficult in the research of engineering reliability analysis.However,the research on reliability of composite foundation is not so much.This paper formulate limite state equation of different composite foundation by the formula of limit bearing capacity of composite based on research result and statistical data.Compile the carresponding program with FORTRAN90 based on the computational method. of reliability index(Monte carlo method and optimize method).Compute the reliability index based on practical engineering example and mock example and show the process of reliability analysis.The method to design the parameter of composite foundation based on reliability analysis was given in the paper.Draw the relation map of reliability index and mean-value of random variables,considering the difference influence degree about different random variables to reliability of composite foundation.The sensitivity coefficient that can reflect the influence degree about random variables to reliability was given and set up the theory frame for design of composite foundation based on reliability.