A Project of Soft Soil Subgrade Settlement Prediction Using Curve Fitting and FLAC3D Numerical Fitting Analysis
Abstract
On the basis of the actual situation of a highway project, combining with pre-engineering geological exploration data and test data later in the laboratory, the settlement analysis on the three typical sections of three situation which can represent this bid project of soft soil subgrade in this article, by using the curve fitting method and FLAC3D numerical simulation method for the calculation.
Through the comparison of the results of the two analysis methods, it can see that the fitting results from the curve fitting method comparing to that from the FLAC3D numerical simulation method are much more close to the measured settlement data. The result shows that the curve fitting method is more suitable for the actual situation of the project and this method can also be used on the settlement prediction of the other road of this bid project of soft soil subgrade.
In the general section of this project, the curve fitting method can be applied and better fitting results also can be obtained. But for some interface whose soil properties have changed a lot, the FLAC3D numerical simulation method can be applied on these special sections to do the simulation calculation. However, in using the FLAC3D numerical simulation method, the parameters and the model should be selected strictly, the error can be reduced in to the required rang. The analysis results of the settlement prediction on three typical sections in this areticle have a certain reference value for the foundation treatment during the Wu and Chu Avenue Project and other similar soft soil subgrade engineering.
Keywords：Soft soil subgrade；Curve fitting；Numerical simulation；Settlement prediction；foundation treatment
1 Introduction
In the process of highway construction, the subgrade settlement is an important factor on the quality of highway construction. In order to meets the requirements of highway construction on the subgrade quality, the trend of subgrade settlement should be grasped and the construction time of each layer of subgrade should be adjust or determined on time according to the changes of the subgrade settlement. Also, timely and effective measures should be taken for possible larger subgrade settlement to avoid the influence on the quality of highway construction[1].
In recent years, with the rapid development of highway in our country, methods of informatization construction are widely used on the construction of the soft soil foundation, high filled roadbed and other bad conditions.
The informatization construction is the method that it is always analyzing the actual test information in the construction process and the analyzing results then to guide the construction or modify the original design[2].
So the information construction method can effectively solve the quality problems of highway roadbed caused by the much serious subgrade settlement and the scientific and reasonable construction of embankment can be arranged.
In the past in the calculation of the subgrade settlement, usually the Terzaghi's one-dimensional consolidation theory is used. However, the computing results are often unsatisfactory and are far vary from the measured data. Also the results are difficult to be widely used in the settlement prediction of the practical engineering. Mainly because the subgrade settlement is usually on the three-dimensional strain and the one-dimensional consolidation theory is difficult to reflect the nature of the problem[3]. So the settlement observation data of settlement prediction are important in the practical significance.
2 Project case
2.1 Engineering
Since 2008 the Ezhou City which is core layer of the city circle has been into a new stage of development[4]. With a series of major opportunities such as the city transformation of Hubei steel city, comprehensive freight yard construction of the Sanjiang port, the east stat
