Simulation of Some Features of the Swelling in Porous Media.

A results of experimental and theoretical study of clay swelling are presented in this work. The model is based on previously developed evidential base showing that alteration of water density should be taken into account during investigation of such processes as water uptake under clay swelling and squeezing water out in clay rocks. From that evidential base it follows that another form of mass balance equation for water should be used instead equation of flow in ordinary porous media. Physically it is caused by formation of quasi-stable films of water which have density different from that of ordinary gravitational water, which was reflected in the mass balance equation of the model. Experiments were performed on the custom setup, experimental procedure was accorded with mathematical model of the process. The model of flow in swelling clays is based on the idea of alteration of density of water, stored between particles of clay minerals in microaggregates of clay. The alteration is caused by action of superficial forces from the clay particles in course of swelling/shrinkage processes. These forces influence on structural bonds of molecules of interlayer water and change their properties. We make an effort to take this change into consideration in explicit form during deduction of mass balance equation for water in case of filtration in clay rocks. This approach has two major advantages. First advantage is concluded in clear and natural procedure of experimental verification of theoretical results. Second advantage is discovery of important role of physically significant factor that influences on processes of clay swelling and shrinkage. The proposed model can describe various flow regimes, including blow-up regimes, and formation of long-existent zones with altered flow structure, which has significant practical importance for description of moisture transport and dynamics of water-retaining properties in swelling soils. [ABSTRACT FROM AUTHOR]