Study On Bearing Behavior Of Man-Excavated Rock-Socketed Piles

Because of the high bearing capacity and small settlement,rock-socketed pile as the base of Bridge and high-layer Building has been widely applied since Nineties.The bearing property of rock-socketed pile has always been concerned by engineering and academia.For the complicated interaction of pile-soil-rock system,rare intact test data,bearing behavior of rock-socketed piles is hard to comprehensive understanding.In this paper,the influencing factors such as characteristic of soils,intensity of rock,the depth of rock-socketed,the ratio of pile and rock module which has effect in the shaft resistance and base resistance are studied.Based on the work mechanism of rock-socketed piles,an in-depth study is carried about the bearing character of rock-socketed piles.Different construction will bring the different bearing character.In this paper,comparing the bearing behavior of bored rock-socketed piles,the shaft and the base resistance and the bearing character of man-excavated rock-socketed piles are discussed.Based on the test results of rock-socketed piles in Jiangsu Electric Network Control Center,some important conclusions about transfer function of shaft resistance-settlement and base resistance-settlement are drawn.At the same time,size effect of base resistance and depth effect of shaft resistance in pile-rock interface are discussed.Finally,depended on the edition of《Specifications for Design of Ground Base and Foundation of Highway Bridges and Culverts》(JTJ 024-85),the test data about 40 man-excavated rock-socketed piles have been collected,some useful conclusions about soil exerting coefficientζs,shaft resistance exerting factorsζr and base resistance exerting factorsζp are drawn.