The study of the relation model between elastic modulus and porosity in deep coal seam roof sandstone

Abstract

Rock mass’s elastic modulus is closely related to its compositions,inner structural characteristics and stress-strain state.By assuming the elastic modulus of pore that as a part of rock is zero,a relational model between the elastic modulus of the whole rock and component as well as volume fractions was derived in this paper.The parameters in this model of deep roof sandstone were determined by the experimental measurements of different brittle rocks such as granite,deep coal rock,roof sandstone and high cementation sandstone prepared by artificial proportioning.In addition,the acoustic emission experiment of cyclic loading and unloading on deep roof sandstone was conducted to determine the change rule between elastic modulus in the rock elastic phase and porosity.The experimental results show that the average error between the theoretical calculated value and experimental measurement value of the elasticity modulus was 2.11%,which proved that relation model between elastic modulus and porosity under stress was applicable.

Keywords

• elastic modulus
• porosity
• rock components
• deep rock
• acoustic emission experiment