Nonlinear Time Series Model Of Deformation On Soft Soil Roadbed And Its Application Study

The warp of soft soil foundation is much complicated and the factors affected are much more. It's difficult to fit and predict the warp of road foundation just from the model setted up from the warp principle itself. The thesis stars from the warp material got in the practice,and sets up the road warp model from the much information that affects the warp factors.The main content of the thesis is as the following:(1) It states the basic peculiarity and the principle of the steady of road foundation and the warp settlement, sums up the necessity of the predict of soft soil road foundation warp, analyses the difficulty and the questions unsolved existing in the predict of soft soil road foundation settlement,and simply introduces both the advantages and disadvantages and the wide utilization of time series.(2) It explains the basic concept of time series, some kinds of the common time series models and the development characteristics of time series in detail. It analyses how to judge the model from the self-related function and the deviation related function. Determining a better standard to set up models from the comparison of some kinds of fixed step time series standards, then predicts utilizing the counter function.(3) It introduces the study significance of chaotic the time series, explains the basic theory and three kinds of predict models of the chaotic time series, and makes sure the step that counts the biggest index number Lyapunov.(4) The thesis converts unrest model (ARIMA model )of time series to the rest model (ARMA model ) of time series. It sets up models acrossing some procedures, such as model identify, factor estimation, model check, ect, then predict the development short-term warp of road foundation. It predicts the time of the filling soil of the next grade utilizing the growth theory of the strength of the road foundation, assures that the working organization and design go smoothly during the filling work of road foundation and saves time and money.(5) Another is the long-term predict utilizing the biggest index number Lyapunov in the chaotic time series and the whole space method during the steady period of the road foundation load, after the overload of the road foundation finished. Meanwhile, contrasts with some mature settlement predict methods, estimating some important section in the engineering synthetically, making sure an ideal outcome of the predict warp, then unload the overload ofroad foundation and make it satisfy the design request.Though the predict methods in the thesis are widely used in every field and acquire better consequence, but the methods using in the predict of the high way road foundation warp are little, especially reported little in the settlement predict during the period of filling soil. The author of the thesis does some pioneer study on it.