Void ratio measures compactness of ground soil in geotechnical engineering. When void ratios are sampled in certain area, measurements are often collected on other engineering variables together with them and generally the sampling grids are sparse in horizontal directions while quite dense in vertical directions. 3D property modeling aims at predicting overall distribution of property values from limited samples, and geostatistical methods can be employed naturally here because they help to minimize the mean square error of estimation. To construct 3D property model of void ratio, cokriging was used considering its mutual correlation with water content, which is another important soil parameter.
However, different variation scales or anisotropies in variograms should be taken into account because of the sampling characteristics. Moreover, K-D tree was adopted to organize the samples to accelerate neighbors query in 3D space during the above modeling process. At last, spatial configuration of void ratios’ distribution in certain engineering body was revealed through 3D visualization, giving most apparent instructions to civil engineering.