This paper experimentally investigates the lateral deformation characteristic of clay under consolidation with lateral drainage. A transparent consolidation test device was developed to obtain photo images of the soil specimen during lateral drainage consolidation. Particle Image Velocimetry (PIV) was applied to quantify the displacements within the entire clay specimen, and subsequently, the strains and void ratio fields were computed through the moving least square method. The results of the PIV showed complex lateral deformation characteristics depending on the degree of consolidation and the locations. The lateral deformation induced a lower void ratio, and consequently, permeability near the vertical drain compared to the average values of the entire specimen. Additionally, the non-uniformity of the effective stress state, and hence of the soil stiffness, was verified with the total stress measurements.

Underground space is being utilized due to the saturation of surface ground. The box culvert, as a representative infrastructure that has moved underground, is installed to protect such fixtures as electricity and gas. Because buried box culverts are necessarily affected by soil, it is important to study the earth pressure according to soil type. Herein, the horizontal earth pressure of the buried box culvert was analyzed. Accordingly, a precisely simulated centrifuge model test was performed. Additionally, the coefficient of earth pressure was analyzed. The results had significant variability because, in the existing theory, the horizontal earth pressure acting on the side of the box culvert was only calculated using the coefficient of earth pressure and the friction angle of the soil. Therefore, a correction factor was deemed necessary for calculating the horizontal earth pressure acting on the side of the box culvert.

Due to the lack of surface space, most structures are heading underground. The box culvert is underground infrastructure and serves to protect the buried structure from the underground environments, but it has a different characteristic from other structures in that the inner space is empty. Therefore, in this study, the vertical earth pressure which is the most significant effective stress acting on a box culvert was measured by conducting a geotechnical centrifuge model test. A box culvert was installed following the embankment installation method, and the vertical earth pressure acting on it was measured considering the cover depth, gravitational acceleration, and loading and unloading conditions. The soil pressure measured was greater than the existing theoretical value under high cover depth and the unloading condition, which is considered as the variability of many soils or the residual stress acting under the loading condition. Finally, a goodness-of-fit test was conducted as a part of variability analysis. The measured earth pressure was found to be considerably larger than the existing theoretical value, and the variability was large as well. This means the existing theoretical equation is under-designed, which should be reflected in future designs.