Abstract:

The hardening soil (HS) model has been one of the most widely used constitutive models in numerical simulation of soft soil foundation pits. However, due to its more model parameters, many parameters cannot be obtained directly from the investigation report. In order to solve the problem of model parameter values, the two kinds of typical soil samples, sludge and silty clay, are selected in Ningbo area. The stressstrain curves of soil are obtained through standard consolidation test, triaxial consolidated drained test and triaxial consolidated drained loadingunloadingreloading test. And then the HS model parameters of the typical soils in Ningbo, i.e.Erefoed、Eref50、Erefur, c′, φ′and Rf, are determined according to the stressstrain curves. Meanwhile, the relationships among the parameters are obtained. The test results are compared with those of soft soil in Shanghai and Tianjin. Finally, threedimensional finite element analysis is carried out for the crossstreet tunnel foundation pit on Xindian Road. The calculation results are close to the monitored data, which proves that the HS model and its parameters obtained by test are applicable to numerical analysis of foundation pits in Ningbo.

Key words: soft soil area, hardening soil (HS) model, modulus, numerical simulation, triaxial test, consolidation test, foundation pit