Incremental Approach in Cover-Cut Method Used in Metro Station's Construction

At present, the effect of the metro station construction under the city arteries to the traffic on the ground is becoming a serious problem in big cities like Shanghai. To solve this problem, based on construction experience and research, a new improved method (cover-cut) is put forward and practiced a lot in Shanghai in recent years. In this paper, the cover-cut method is presented. The calculation method about the new type cover-cut construction is also discussed. The summation approach method which ignores the effect of the construction process is widely-used in solving similar problem in China. In fact, the variational load and the partial finished structure is the most crucial status in the whole construction process, accidents always happened in this course. In this paper, the incremental calculation method which is also named as "step-by-step" approach method is presented. At the end of the paper, a case is discussed and calculated by two methods which showed the difference between the incremental method and the summation method. The discussion showed that the results calculated by the "step-by-step" approach method are more accurate than which calculated by the summation method.