Feasibility Test for Jacking Root Studs of Root Type Caisson Foundation Under Water

The underground water at the site of Maanshan Changjiang River Highway Bridge is very abundant.To verify the feasibility of jacking root studs of the root type caisson foundation in the environment with water,the test for jacking the studs of a caisson foundation of such type under water was made in the field.The caisson was first sunk to its designed elevation and the bottom sealing for the caisson was done.The studs were installed in the caisson the dry environment and the caisson was filled with water.The diver then dived into water to the designated place in the caisson where he would jack the studs into the soil outside the caisson.The results of the test show that the jacking of the root studs under water is smooth and safe.The time for jacking of a single stud is 12 h which is 6~8 h longer than that of a stud in the dry environment.In the process of jacking,no abnormalities happened and the jacking of the studs under water is feasible.