Calculating the Strength Parameters from Vane Strength and Its Use in Cylindrical Caisson foundation Design

The safety factors of the new foundation type for breakwaters,the cylindrical caisson foundation,are closely concerned with the strength parameters.In Tianjin Harbor,the foundation soils are soft clay with underconsolidated condition,low bearing capacity and high water content.The vane strength is more frequently used among the currently used strength parameters in assessing the stability analysis of the structure during the construction stage.Research results have shown that the vane strength is the smaller one comparing with the strength on other shear surfaces.Furthermore,a single value of vane strength can not meet the requirements for calcula ting the earth pressure and bearing capacity.This paper presents a new approach which can deduce the two conventional strength parameters based on the linear distribution of vane strength along the depth and the Mohr-Coulomb strength mechanism,by the statistical regression methods.The deduced parameters have been used to calculate the stability of the cylindrical caisson foundation.