Determination Method for the Strength Model of a Jointed Rock Mass Based on the Geological Strength Index

The mechanical characteristics of materials are the key to numerical calculation, the determination of material parameters of jointed rock mass is conundrum in academia. For the purpose of more efficiently and accurately select the mechanical parameters of the jointed rock masses, in this paper, a new method is proposed which for constructing a numerical model of jointed rock masses, which based on the Geological Strength Index ( GSI ) and the principles of damage mechanics. With the help of basic concepts of damage mechanics, the joint equivalent coefficient is proposed, establishing the relationship between GSI and joint spacing. The selection way for the mechanical parameters of a jointed rock masses is given in combination with the Hoek-Brown strength criterion. Then, a numerical calculation model is constructed by utilizing 3DEC numerical simulation software to discuss the stability of the adjoining rock under the condition of different GSIs , which is successfully applied to the Wangjialing coal mine project. The numerical results match quite closely with the field conditions, the maximum error is 18%, the minimum error is 5.6%, verifying the rationality and accuracy of this way and providing a new way for the accurate numerical simulation of jointed rock masses.