Analysis of principal stress distribution in tunnel stability

The Jatigede Dam is an embankment dam and one of the largest in Asia and is located in the Cimanuk Watershed with an area of 1,460 km 2 .Without proper design and analytical calculations in tunnel construction, soil stress will cause deformation and cracking of rocks in the area around the tunnel.During the construction process, tunnel excavation causes deformation and redistribution of the initial stresses in the rock mass.Analysis of tunnel stability with reinforcement needs to be done by numerical methods.This study aims to determine the principal stress distribution and the effect of lining reinforcement.Numerical analysis needs to be carried out to analyze the stress distribution and displacement in the tunnel excavation area.Segment 1 at STA 0+05 has the greatest overburden so that the vertical in situ stress is also the greatest.Before the reinforcement was installed, the maximum 1 was 0.49 MPa at the tunnel floor.After installing the lining reinforcement, the maximum 1 is 1.32 MPa in the rock layer on the left side of the tunnel.The total displacement before being reinforced was 4.256 meters.After being given lining reinforcement, the total displacement became smaller, namely 0.01 meters.The direction of relative displacement tends towards tunnel excavation.Lining reinforcement using concrete pipes with a thickness of 0.23 meters in each tunnel segment.Numerical analysis produces detailed reinforcement in a comprehensive manner.From the results of the analysis of the distribution stress, it is found that the greatest stress is on the tunnel wall.The amount of displacement before and after the lining reinforcement is quite significant.