Experimental study on subgrade reaction under raft foundation prestressed with unbonded tendon

Through largescale field measurements and comparative analysis,this paper reveals the law of the subgrade reaction distribution under the raft foundation prestressed with unbonded tendon and the influence of prestress on the subgrade reaction distribution.The firsthand data of an insitu test of the foundation are presented.Furthermore a synthetical method of insitu and laboratory calibration tests on earth pressure cells is discussed.