Efficiency evaluation of empirical models on the basis of rock mass rating for prediction of deformation modulus in rock mass and developing a new models according to the fuzzy system

Summary
Prediction of deformation modulus for rock mass in analysis and design of rock structures is very important. Because deformation modulus represents behavior of rock mass subjected to stresses. Up to now, various empirical models for prediction of deformation modulus were developed. In this research, efficiency of different models for prediction of deformation modulus is evaluated. Latter, according to the fuzzy model a sufficient model is developed and results are compared with the empirical models. Results indicate the efficiency of new proposed model in comparison with the available models. Determining geo-mechanical parameters for analysis and design of rock structure is inevitable. Deformation modulus of rock mass is one of the most important geo-mechanical parameters. Estimation of deformation modulus for rock mass utilizing empirical models is widely used in civil and mining engineering projects. This is because of by spending less time and cost an acceptable estimation is achieved. But there are differences between results of empirical model and real values of modulus which leads to uncertain decisions for designers in choosing appropriate model. Thus, it is important to investigate and evaluate the experimental models. Fussy model is one of the best models that is proposed for determining the deformation modulus in the present study. Methodology and Approaches For efficiency evaluation of 19 available models and also the proposed model, 33 data sets of different dam’s constructions in Iran is collected. Root Mean Squared Error , Mean Absolute Percentage Error and index of higher squared correlation coefficient are applied for evaluation of models’ performance. According to the performance indices two models are selected between different empirical that indicates the best prediction. Also results show the efficiency of proposed fuzzy model for prediction of deformation modulus.