Synthetic low-strength materials as rock substitutes for physical model studies

Abstract

The mechanical behaviour of rocks can be conveniently studied using physical model tests under controlled conditions. Most of the physical models reported in the literature use natural rock samples. Being natural materials, rock samples can show widely varying mechanical and hydraulic responses. The varying responses make the interpretation of testing results difficult and even hinder the study of a selected phenomenon. On the other hand, the use of synthetic materials with customised mechanical properties can favourably reduce the influence of heterogeneities on the material behaviour, while maintaining fundamental mechanical behaviour of natural materials. In addition, randomness can be later included in synthetic materials to mimic natural materials. This paper presents two new synthetic materials and their carefully designed fabrication procedures to obtain reproducible samples. The design aims for low-strength brittle materials that can reduce the complexity and even the cost of experimental set-ups where the loading machine with lower stiffness can be used. Two types of materials are developed: (1) permeable-brittle; and (2) transparent-impermeable-brittle. These materials can help with experiments such as hydraulic fracturing. Standard tests are performed with these synthetic materials. Results demonstrate great advantage of the proposed synthetic materials.