Properties of rock mass deformation of siltstone in the Simaki formation (Elazig)

The aim of this study is to determine the rock mass deformation properties of the Maestrichtian-Late Paleocene aged siltstones of Simaki Formation, rock mass characteristics of siltstones along with to investigation relationships between rock mass deformation features and rock mass attributes of siltstones. Beside these, without performing in-situ field experiment to purpose empirical equations with which one able to determine rock mass deformation modulus and to designate whether layering orientation well-bedded rock mass has any effect on rock mass deformation modulus.The Siltstone rock mass consists of four discontinuity teams which are including three joints and a bedding. The slope and slope direction of these joint teams are 40/164, 77/211, 55/286. The slope and slope directio of the bedding are 33/135. Discontinuity spacing, discontinuous aperture, the discontinuous continuity, weathering degree , roughness, infilling of the Siltstone rock mass are close-medium spacing, moderate wide-open feature, medium-high persistence, slightly weathered, planar rough, calcite-filled, respectively and water on the layer of surface is not observed.A total of 50m geotechnical inclined drillings has been made on between 0 - 90 degree angles varying of 10 degree intervals at 12 different locations designated on study area. Pressuremeters experiment have performed with the aim of the determine rock mass deformation modulus in-situ at every meters of drilled-wells in addition geomechanical testings have made, in accordance with, objective of study, testing have made on core samples chosen from geotechnical drillings.According to the results obtain from field and laboratory works, of the siltstones mechanical and elastic properties investigated anisotropic exchange on between 0 - 90 degree angles varying of 10 degree intervals. Siltstone rock mass deformation modulus, pressuremeter get is determined by experiment, the value is between 0.32 GPa with a 10.49 GPa.With the aim of indirectly determining deformation modulus of the Siltstone rock mass, value-ranges of the performed rock mass classification such as RMR, RMi, GSI and RQD in the Siltstone rock mass are 41.3 to 62.3, RMi 0.21 to 3.75, GSI 40 to 54, RQD 11 to 98, respectively.The relationships between these parameters and rock mass deformation modulus are studied via simple regression analysis and meaningful empirical correlations are purposed these equations have show that there is very strong positive correlation (r = 0.89) between Em and RMR, a strong positive correlation (r=0.86) between Em and RMi, a strong positive correlation (r=0.76) between Em and GSI and again a strong positive correlation (r=0.70) between Em/Ei and RMR.The performance assessments of these equations are investigated with RMSE, VAF and cross correlation analyses, a good performance is found. On the other hand, a strong positive correlation (r=0.66) between Em/Ei and RMi, a strong positive correlation (r=0.69) between Em/Ei and GSI and again a strong positive correlation (r=0.61) between Em/Ei and RQD are found but, at the end of performance evaluation it has been determined that the performance of these equations are weak.When relationships between rock mass deformation modulus and discontinuity orientation are examined, it is found out that correlation between Em- ? (r = 0.73), Em/Ei- ? (r = 0.95) are strong and very strong. It is observed that Em and Em/Ei values are at maximum when the angle ?? is between 0? to 90? degrees, in addition to Em and Em/Ei values are at minimum when the angle ?? is between 45? to 55? degrees.