A microstructural computation simulation model of loess soils

A major geotechnical problem encountered with loess deposits is structural collapse upon saturation under load, a process known as hydrocollapse. To elucidate this problem at a microstructural level a computer simulation of the soil has been developed using Monte Carlo random number theory. This enables models to be produced encompassing a variety of microstructural fabrics observed with loess, from the initial formation to the development of a metastable structure and ultimately the hydrocollapsed structure. The influence of particle shape and size on the structure, and the void ratio, are analysed. A physical model has been created in parallel to the computer simulation in order to validate this work. The results from the two types of model correspond well, with void ratios of between 1.2 and 1.6 being obtained for the initial structure; 0.9 to 1.1 for the metastable structure; and 0.5 to 0.7 for the hydrocollapsed structure. The resulting reduction in volume, occurring suddenly, constitutes a serious geohazard.