LABORATORY STUDY ON PROPORTION OF SIMILAR MATERIAL FOR SIMULATING ANCIENT WEATHERED ROCK IN COAL STRATA

This paper is to prepare the similar material specimens with gradual variation of mechanical properties. The proportion tests is used to achieve the relationship between mechanical properties and proportion of cement-gypsum similar materials with different aggregates. A defined formula of proportion based on compressive strength and elastic modulus is determined via fitting the laboratory mechanical testing data of river-sand material. The test result shows that: water dosage, forming pressure and average particle diameter have effect of different levels and should be controlled in specimen preparation process. The tensile strength of low-intensity similar material is uncontrollable while the compressive strength and the elastic modulus show an obvious response to the change of proportion. For river sand similar material, the mechanical properties and the proportion present a linear relationship. While the standard sand similar material presents a nonlinear relationship between the mechanical properties and the proportion due to the critical content of cement and aggregate. The variable ranges of compressive strength and elastic modulus are 0～17.5MPa and 0.3～2.02GPa, respectively. The weathered rock can be simulated well using similar material in this range.