This paper presents a procedure which estimates a less-sampled variable such as the internal friction angle or the cohesion with acceptable precision using a better-sampled variable such as N-value. Incorporating the regression relationship between a better-sampled variable and a less-sampled variable into the cokriging method, the cross-covariance function is easily determined, then the better estimation of the less-sampled variable is obtained.
In a numerical example, the bearing capacities of four foundations supported a transmission tower are calculated using the internal friction angle and cohesion estimated by this proposed procedure. The calculation results are compared with those of calculated according to the current specifications.