Water content of soil matrix during lateral water flow through cracked soil

Abstract

Two types of flow occur when a network of cracks in a soil mass becomes filled with water. The types of water flow are lateral water flow through the network of cracks and water seepage into the intact soil matrix. The pattern of water content changes within the intact soil matrix part of a cracked soil due to water seepage is different from the pattern of water content changes due to water seepage in an intact soil. The soil matrix located closer to a crack has a higher water content than those located further away from a crack. A method was developed to determine changes in water content at various positions within the intact soil matrix part of a cracked soil. The proposed methodology involves modelling the water in the cracks as head boundary conditions alongside the walls of cracks. The analysis used a numerical solution of a differential equation for an intact soil. An idealized network of cracks was used to represent the cracks in the soil. Laboratory experiments were used to investigate the performance of the proposed method. The experiments mainly consisted of the measurement of water content at several locations within the intact soil matrix part of a cracked soil at various distances from the cracks during and at the end of lateral flow tests. Comparison of the numerical analysis results and the experiments results provided verifications of the proposed methodology. Modelling of the network of cracks using head boundary conditions showed close agreement with the laboratory measurements.