Error analysis of settlement predicted by accumulative prediction method                                                                                            

Since the stage construction is typical for embankments and the ground is usually in layers,the curve of the measured ground settlement-time is accumulated by the curves of settlement-time corresponding to different ground strata and embankment construction stages.The theoretical analysis and project examples show that the curve of the accumulated settlement-time is not usually exponential or hyperbolic.Based on the above,the accumulative prediction method and respective prediction method are put forward.It is proven by error analysis of settlement predicted by the accumulative prediction method that the error is influenced by the β ratio of strata,the time interval of loading stages and whether or not the employed function reflects the true situation.Different strata with equal β can be taken as the same stratum.If the function employed by the settlement prediction is not the same as the true one,the settlement predicted by the respective prediction method has errors too.The settlement predicted by the accumulative prediction method is less than that by the respective prediction method and usually less than the true settlement.To reduce the error of the predicted settlement and large starting time for the settlement prediction,the respective prediction method and improved exponential method or hyperbolic method are suggested.