ESTİMATİON OF THE SHEAR STRENGTH OF NATURAL JOİNTS USİNG GENE EXPRESSİON ALGORİTHM

Studying the shear behavior of rock joints due to its significant effect on the stability of structures is very important. In this regard, important and valuable works have been done. Many empirical and theoretical models have been proposed to estimate the joint shear strength. The ultimate goal is to predict the joint shear strength through known parameters without carrying out tests. This study investigates the shear behavior of natural rock joints obtained from core drilling without filling materials. For this purpose, the surface morphological characteristics of the natural joints were captured by Close-Range Photogrammetry. The direct shear tests were performed on the Constant Normal Load condition. The Gene Expression Programming algorithm was used to obtain the relationships between variables. In order to model 70% of data were used to train and the remaining 30% of data to test. Overall, four models were run and a mathematical relationship was presented to estimate the shear strength of natural rock joints. To evaluate the efficiency of the models, valid criteria were used such as: R2, MSE, MAE, RSME. The results showed that the GEP algorithm has an appropriate accuracy for the estimation of the output variable.