Study Of Axial Bearing Properties Of Cast-In-Situ Pile In Xigeda-Rock

The Xigeda-rock is widely distributed in Xichang-Panzhihua region in Sichuan Province. It belongs to extreme soft-rock with special characteristics, for example , it can be mashed and softened by water and will rupture when being dehydrated. The research datum about cast-in situ pile in this rock is badly scarce. The clear and complete computational methods in current criterions have not yet been found.Based mainly on the subject " Testing Study on Bearing Properties of Pile Foundation In Xigeda-Rock " under the western traffic scientific research project" Research on Highway Construction Techniques in Xiged-Rock ", and associated with provincial scientific research project " Testing Study on Bearing Properties of Bored Pile in Xigeda-Mudstone in Xichang-Panzhihua Expressway", this paper conducts comparatively systematic research. Firstly, in accordance with the materials of the vertical static load test of the single pile, the author analyses the working rules of the axial pressure, side friction and tip resistance of the piles. Secondly, the predicting methods of the bearing capacity of the single pile are inducted. On the grounds of the testing datum of the load and displacement, the axial bearing capacity of the single pile in the Xigeda-rock is predicted. Drawing a comparison among the calculating results of all the predicting methods, the author analyses the traits of the calculating results and works out a reasonable predicting method of bearing capacity of the single pile in this kind of rock. The method can reflect the true conditions of the Q S curve. Finally, on the grounds of discussing the calculating formula of the bearing capacity of the single pile in the current specifications, the author analyses the calculating methods of the side friction and tip resistance of the cast-in-situ pile in Xigeda-rock and brings up a calculating formula correspondingly.