Back Analysis Of M-value Of Foundation Soils In Hangzhou

Foundation structure design in soft soils is a very difficult engineering problem.The elastic foundation beam method has some merits such as easy calculation pattern and definite model and m-method is fit to practical situation, so it is used comprehensively and welcome by constructors,thus m-method is recommended by many Codes.But it is difficult to select a m-value to some soils,and the Codes provides a scope of m-values,and they are different in varied regions and soil conditions,thus it is optional to choose m-value of a soil layer for engineering designers.So it is necessary to calculate m-values by back-analysis method using measured datu of deep foundation pit.For this purpose, this paper first gives a description of recent research advances and a brief introduction of back-analysis method.Second, the development of ditches excavation in Hangzhou is introduced and some often used types of the exterior-protected structures are illustrated. And m-method is stated in detail recommended by the Code.Then,the effects of the inner force and displacements of the exterior-protected structures influenced by the value of M and the different depths of inner poling are analysed with the M-Method back-analysis programme. And the variation of optimized values caused by the numbers of different inversion parameters is also analysed,and a conclusion is drawn that a propriate parameter numbers should be in use of back analysis.Finally, based on some measured datu, the sutable values of M for Hangzhou Region is obtained and some useful conclusions are drawn for constructors.