The estimated method of ultimately loading of pile foundation based on catastrophe theory

The ultimately loading of pile foundation is very important for the engineering design. The accurate estimation is the base of security of structure and avoids the engineering accident. In engineering, the static loading test is most near to the process of bearing capacity and estimation of ultimately loading is the credible value for designing. Sometimes, the ultimately bearing capacity of pile foundation is difficultly estimated on the base of the relation of displacement-loading. So it was important to detect an effective method (the method of E-Delta s/Delta P curve) to estimate the ultimately loading, based on the cusp catastrophe theory and the failure characteristic of pile-soil system. Ultimately loadings of four kinds of pile foundation were estimated and were compared with values of ultimately loading by the means of the P-s curve method, LogP-s curve method, load-transfer method and finite element method for limit analysis (the strength reduction method, increment loading method). Comparison of results shows that the E-Delta s/Delta P curve method can easily and credibly estimate the ultimately loading and it is widely fit for various kinds of pile foundation.