Study Of Bearing Behavior Of The Large Diameter Rock-socketed Pile

Rock-socketed pile is pile embedded in rock mass.With the advantages as high bearing capacity,settlement can be controlled,seismic performance outstanding,the rock-socketed pile can adapt to all kinds of conditions of complicated engineering field,and therefore is widely used in various engineering fields,such as Bridges,docks,tall buildings and other construction sites.Today,the large diameter rock-socketed pile has become a widespread used pile type by the construction of port terminal in the Yangtze river,so the research of large diameter rock-socketed pile load-bearing characteristics,has very important practical significance.In recent years,with the development of the national civil engineering construction,the theory of rock-socketed pile has brought to the attention of the theory and engineering.This thesis does the main work as follows:(1)By consulting relevant literatures at home and abroad,the bearing behavior and load transfer mechanism of rock-socketed piles under vertical loading are are systematically summarized and analyzed.Combined with pile-This paper describes the calculation of the bearing capacity of rock-socketed piles,analyzes the reason why the design of rock-socketed piles is conservative in the calculation process,and expounds the applicable conditions and characteristics of each standard.(2)The load-bearing characteristics and settlement characteristics of large-diameter rock-socketed piles are discussed through the tests of rock-socketed piles,rock-socketed pile test,pile-side friction resistance test and numerical simulation of the original rock model,provide guidance for the design and construction of large-diameter rock-socketed cast-in-place pile.(3)According to pile friction force-displacement curve of the in-situ test,puts forward suitable calculation model of load transfer method,and gives analytic expression and compare to the original rock model test.(4)According to the test results and the numerical simulation,the influence factors of the bearing characteristics are analyzed.The load transfer mechanism of rock-socketed pile is a very complicated process,which is affected by many factors,need to make the pile,soil and rock work together.When rock-socketed piles play a role of bearing,the bearing capacity is a top-down,from the overlaying soil pile side friction,to the rock-socketed part side friction,finally to the end resistance.The calculation formula of the current code can not fully reflect the actual working behavior of rock-socketed piles.The load-displacement curves of the rock-socketed piles and the rock-socketed piles are all slow deformation.By increasing the pile diameter,increasing the depth of the rock-socketed rock,increasing the roughness of the hole wall and increasing the rock strength around the pile Bearing Capacity of Rock-Socketed Piles.The distribution of pile-side friction along the pile body is "big and small",which is located at the top and bottom of the rock-embedded section,and the upper peak value is greater than the lower peak value.The lateral friction resistance of pile side is positively correlated with the bedrock strength,and negatively correlated with the rock depth.The resistance of the pile tip is lagged behind the pile side resistance.The pile-end resistance share ratio of the sandstone piles is bigger than that of the mudstone rock-socketed piles.