STABILITY ANALYSIS OF A LARGE UNDERGROUND CAVERN IN SQUEEZING GROUND CONDITION

Abstract

it is extremely difficult to construct a large sized structure in any difficult ground condition. For a proper understanding of the possible difficulties that could be encountered during the construction and service span of the structure it is mandatory to have a prior prediction of all the possible difficulties. Underground excavation being larger in its dimensions has a great possibility of encountering the unpredicted geological formations during excavation especially in squeezing ground condition. Thus for a proper estimation of the support system required and the proper time of its installation it is mandatory to have a prior stability analysis of such a structure. Empirical available methods do not consider all the parameters encountered during any structure so for a better correlation of the observed behavior numerical modeling could be fruitful. In this dissertation an attempt has been made to numerically model the Chhibro-Khodri power house cavern considering the thickness of shear zone and a - comparative study is done for different parameters available. The power house cavern is modeled as a two dimensional plane strain problem using finite element based phase2 software and a elasto-plastic analysis is carried out for different cases. The support system is idealized to be installed in three stages and the behavior of cavern is studied considering serviceability requirements. The obtained results are compared with the instrumental data available and also fi-orn that of empirically observed correlations.