ANALYSIS OF ANGLE VARIATION AND ROCK STRENGTH IN TUNNEL STABILITY WITH FINITE ELEMENT METHOD

• Main Author: NAILA DIANIPUTRI (NIM : 12114010), ANNISA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25671
• Institution: Institut Teknologi Bandung

At the beginning of tunneling especially on underground mining, there will be an anisotropic rock which resulted a deformation of the rock mass surrounding a circular tunnel. To plan an effective and efficient mining activities, required an analysis of stress redistribution around the tunnel that can cause instability. To analyze the stability of the tunnel, we can use until the element method. <br /> <br /> In the laboratory, the test was done to know the physical characteristics and the mechanics of layered rocks. The materials of the samples consist of Strong (K) and Weak (L) materials. Material K has 20.68 MPa of compressive strength, and for material L has 9.68 MPa of compressive strength. The samples divided into two types of lamination, K-L-K and L-K-L, with each samples were made with 3 variations angles, which were 15&#61616;, 30&#61616;, and 45&#61616;. Using the finite element method with Rocscience software Phase2 8.0 to modeling the masses of rocks that has the dimension of 50x50m with tunnels that will excavated in circle with a radius of 5 m. In addition, analysis of the collapse that is used was the Mohr-Coulomb criterion. <br /> <br /> There are 2 condition of insitu stress in this research. The first condition is that the value between &#963;v and &#963;h is 1:1, and the second condition is 1:2. The variation of insitu stress will affect the induced stress produced after the excavation because of the changes in stress distribution of the tunnel. Based on modelling results on the roof and the wall of the tunnel, rocks with the L-K-L 15&#61616; layering, produces the highest safety factor. It can be said that, the angle variation and rock strength influence the value of induced stress that produced in tunnel excavation, and also effecting the safety factor of the tunnel.