JOURNAL OF ROCK MECHANICS

JOURNAL OF ROCK MECHANICS

Estimating the rock mass deformation modulus using the statistical and artificial intelligence models

Document Type : Original Article

Author
Department of Mining Engineering, Faculty of Engineering, University of Kurdistan, Sanandaj, Iran
Abstract
Direct measurement of the rock mass deformation modulus using in-situ and laboratory tests is a costly and time-consuming process. Therefore, the use of indirect methods such as artificial intelligence algorithms to estimate this parameter can be a useful, fast, and cost-effective alternative. In this study, the modeling of the rock mass deformation modulus was performed using Gene Expression Programming (GEP), Fuzzy Inference System (FIS), and Multiple Linear Regression (MLR) models. The input data for estimating the rock mass deformation modulus included overburden height, rock quality designation, weathering, uniaxial compressive strength, bedding inclination angle, joint roughness coefficient, and joint filling, which were collected at the Bakhtiari dam site. After modeling, the results from the three models (GEP, FIS, and MLR) were compared with each other, with real data, and with similar previous models. The performance evaluation indices, including root mean square error, mean absolute error, calculated variance, efficiency coefficient, and coefficient of determination, were 1.27, 1.85, 0.9912, 0.9889, and 0.9869 for the GEP model, 1.51, 2.05, 0.9876, 0.9823, and 0.9778 for the FIS model, and 4.45, 4.97, 0.7641, 0.7569, and 0.7444 for the MLR model, respectively. The results indicate that the accuracy of the GEP and FIS models is higher, and their error is lower than the MLR model. Based on the evaluation of the model results and their comparison with real values and the results of previous similar models, the high capability of the two models (GEP and FIS) and their relative superiority over previous studies in predicting the deformation modulus was confirmed. However, the accuracy of GEP is slightly higher than FIS, and its results match relatively better with real values. Finally, the results of the variable importance analysis showed that the weathering and overburden height parameters have the most and least influence on the rock mass deformation modulus in this study, respectively.
Keywords
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