The Applicability Study Of Chord Modulus Method In The Deformation Of Loess Foundation

The reasonable of foundation design is a big problem which related to the safety of the project and the economy.In the foundation design not only to meet the strength required, but also must satisfy the deformation requirement. Especially when built houses on the soft soil foundation, deformation condition become more important. Therefore, the research of the foundation deformation calculation has the vital significance to the design of the foundation.In northwest and north China region loess and loess-like soils is widely distributed throughout several provinces, with a total area of 640,000 square kilometers, collapsible loess distribution of the total area of about 3/4, and has the close relationship between construction. In the past, the foundation design is based on the compression modulus that in the the design code for building foundation (GB 50007-2002) and the collapsible coefficient and the collaspsibility coefficient those in the collapsible loess areas building codes (GB50025-2004). But the practice proves that the computed value and practical results vary considerably. Mr Jiao through years of research, introduce the chord Modulus to the foundation deformation calculation and Propose use the Chord Modulus to Calculation the settlement of the foundation. This method is proved by project examples, in some engineering application is tally with the actual situation. In view of the engineering on the chord modulus method has some controversy, systematic and in-depth study of the method in this paper could help further understanding calculation methods.This paper is based on the strings modulus calculation principle of the foundation settlement. Using Delphi language writing a new set of loess foundation deformation calculation software, to calculater self-weight collapse of the saturated loess foundation, collapse settlement of the collapsible loess foundation when groundwater rises and collapse settlement of the collapsible loess foundation when ground has water. And application software on several different cases of loess foundation settlement calculations, and compared with the measured values, to gave a further explored about whether the chord modulus can directly instead of loading test to get pressure - settlement curve.Obtained by comparing the analysis: the calculated results of the collapse deformation which caused by ground water rise, weight collapsible ground deformation which caused by ground water and the increased deformation which caused by surface flooding is match to the measured results.But the calculation in some cases has some distance between the measured results. It can be seen,use the chord Modulus to calculate the increased deformation of loess foundation need more research,then can better used in engineering practice.