A Prediction Method For Post-construction Settlement Of Soft Subgrade Soil With The Consideration Of The New Or Old Degree Of Measured Data

The post-construction settlement prediction of building foundation or roadbed is always one of the hot issues in the field of civil engineering, it is also one of the important research topics in soil mechanics. For the present existing settlement prediction method, it can be divided into two types, one of which is numerical analysis method that based on the constitutive model and the other is mathematical analysis method that based on the measured data. Since it is difficult to determine the foundation parameters and there are some differences about the constitutive model between the theory and practice, besides, it usually needs much complex calculation. It is difficult to be used widely in engineering. The mathematical analysis method that based on the measured data becomes the most widely used method in practical engineering ever since because of its convenient operation and simple calculation. Scholars have studied the mathematical analysis method widely and deeply, through which a series of effective results have been achieved at present. But there still exists a disadvantage that the present methods of settlement prediction do not consider the effect of the new or old degree of measured data to the foundation settlement prediction at the same time. Therefore, a new method of settlement prediction for single and combined model is to be set up on the basis of mathematical analysis method with the consideration of the new or old degree of measured data.First of all, aiming at the effect of the new or old degree of measured data to the foundation settlement prediction, a new objective function of single model-fitting analysis is established by introducing a fresh degree function, which is used to improving the description method of error between the calculated value and the measured value, in order to obtain a more simple and reasonable and practical method for post-construction settlement of single model. And then, the new method to determine the parameter based on the fitting analysis of measured curve is developed on this basis, thus the new method for post-construction settlement of single model which can reflect the effect of the new or old degree of measured settlement data on prediction.Secondly, the idea of combination prediction is introduced in this paper. With the idea of parallel-modification, a method of the adjustment of value interval for combination prediction is proposed through analyzing the change laws of the probable value of combination prediction, which is in favor of improving the precision of the prediction. And then, on the basis, a new improved method for combination prediction of post-construction settlement is set up, it can simultaneously describe the effect of not only new and old degree of the measured data but also the adjustment of value interval for combination prediction on settlement predictionFinally, the proposed method in this paper is used to analyze the practical engineering examples, which are compared with the measured settlement. It is shown that the proposed method is feasible and reasonable.