Yielded joints in around of tunnel

ABSTRACT: In this paper, the numerical analysis has been performed on the jointed rocksin around of tunnel and factors affecting on the yielded joints such asroughness coefficient (JRC) and compressive strength of joints (JCS) have been surveyed. Shear strength of joint surfaces and also joint dips haveimportant role in the analysis of the stability of underground constructions which designed andimplemented in rock. One way to estimate the shear strength of the jointsand joint behaviour in rocks is using empirical theory of Barton. Joint roughness coefficient (JRC) and joint compressive strength (JCS) are the parameters of this equation. This study used data fromTizhtizhgaran tunnel that have been dug in the shale rocks. In this tunnel modeling, seven dips ofjoints analyzed using Phase2 software and Yielded joints diagrams are plotted on the tunnel sectionsunder static load. The obtain resultsshow that with increasing joint roughness coefficient from 0 to 15, the number of yielded joints in thearound of tunnel is decreased and from 15 to 20, the number of yielded joints is increased. Furthermore, with increasing the dip of joints from 0 to 90, the values of JCS and JRC have greater effect in the number ofyielded joint in around of tunnel.