Analysis And Engineering Application Of Bearing Behavior Of Bored Rock-socketed Piles In Fractured Rock Foundation

In recent years, with the rapid development of economic and the urbanization develops increasingly, many tall buildings, railways,viaducts are built on rock foundation that give a high request on the foundation. The rock-socketed pile foundation plays an imperative role in the construction, because of its high bearing capacity of a single pile, a better seismic performance, and a lower settlement, it is widely used in tall buildings, railways,viaducts engineering. In the national code Technical code for building pile foundations(JGJ94-2008), when the end of pile is on the intact rock mass and less intact rock mass, it can be design as rock-socketed pile.However, in Guiyang area, the end of the piles are mostly built on less cracked rock mass. However, the national pile code didn't make a more detailed statement which brings many problems for rock-socketed pile designing.In this thesis, the main work are as follows:First, introduce the mechanical mechanism of rock-socketed pile, including pile-soil,pile-rock mechanical mechanism, and the interaction between shaft resistance and tip resistance. Discuss the difference of mechanical mechanism on less cracked rock and intact rock mass, less intact rock mass.Second, introduce methods to determine the bearing capacity of rock-socketed pile,especial the in-situ test method and the national code method. According to the properties of rock-socketed pile on less cracked rock, give an improve calculation formula on how to determine the bearing capacity of rock-socketed pile embed on less cracked rock.Then introduce the methods to determine the settlement of pile foundation, including national code of pile foundation method, load transfer method,elasticity theory method and the shear deformation method. Discuss the method to determine the settlement of rock-socketed pile embed on less cracked rock.Third, introduce the failure features of rock-socketed pile, including failure features of single pile, rock mass, the rock at the side of pile and the rock at the end of pile.Discuss the failure features of rock-socketed pile on less cracked rock.Fourth, introduce the factors that influences the bearing capacity of rock-socketed at the side and end of pile. Use the orthogonal test method to study the factors that influence the bearing capacity of rock-socketed pile that embedded on less cracked rock foundation.Fifth,, use the finite element method to have a numerical analysis on the rock-socketed pile.At last, combined with the specific engineering in Guiyang, to make sure whether the improved calculation formula is correct and reasonable or not.Discuss the application of rock-socketed pile on less cracked rock foundation, and give some suggestion conditions on how to use the rock-socketed pile that embedded on less cracked rock foundation.