Calibration of stiffness parameters for Hardening Soil Model in residual soil from Kenny Hill Formation

Abstract

The underground configuration of the Klang Valley Mass Rapid Transit (KVMRT) system passes through two different geological formations namely the Kenny Hill Formation and Kuala Lumpur Limestone. However, this study only concentrates on the Kenny Hill Formation. A set of borehole data from Pasar Seni Station within the Kenny Hill Formation was analysed in order to calibrate the stiffness parameters for Hardening Soil Model of residual soil from the Kenny Hill Formation. The in situ and laboratory tests were simulated using the PLAXIS 2D software. The parameters were determined based on triaxial and pressuremeter tests. From the selected boreholes, the residual soil from Kenny Hill Formation is categorized into five soil types-sand, sandy clay, gravel, silty sand and silty gravel. The triaxial test was carried out for sand and sandy clay at depths of 0-4 m and 2.5-8 m under both drained and undrained conditions, respectively. The pressuremeter test was conducted for gravel at 2.5-10 m depths, silty sand at 6-36 m depths and silty gravel at 30-40 m depths. The outcome of this study is to produce a reliable set of data which will allow engineers to make assumptions more effectively and to avoid the probability of project failure due to unreliable design input parameters. It is found that the Hardening Soil Model is able to represent the real soil behaviour compared to Mohr Coulomb Model. This is due to the stress-dependent stiffness feature in Hardening Soil Model. Hardening Soil Model features a total of ten parameters and it is very renowned due to the stress-dependent stiffness attribute. The parameters of Hardening Soil Model of the residual soil from Kenny Hill Formation was also calibrated and a database was established.