Investigation of the effect of soil matrix on flow characteristics for soil and rock mixture

Abstract

The flow characteristic is important to soil and rock mixture (SRM). Seepage of SRM includes a combination interaction between soil matrix, rock blocks and rock–soil interfaces. Properties of soil matrix play crucial role in controlling the flow rule of SRM, yet the effects of different kinds of soil matrix in SRM on its flow mechanism are still poorly understood. In this work, the authors present the results of a state-of-the-art investigation on the flow properties of SRM with clay, mucky soil and fine sand matrix. A self-developed servo-controlled large-scale permeability testing system was used to carry out the flow test. From the test results, the flow rules are different for SRM with different kinds of soil matrix. For a matrix composition of clay and mucky soil, the flow law follows the non-Darcy law; however, it follows Darcy's law for the SRM with a fine sand matrix. The non-Darcy flow properties are studied with the Forchheimer equation to obtain the permeability coefficient for SRM with different rock block percentages.