CONCURRENT EXCAVATION AND CONCRETING IN LARGE DIAMETER TUNNELS THROUGH SYSTEMS APPROACH

Abstract

The field of tunnel construction planning includes a large number of elements possessing characteristics of uncertainity. The planning becomes all the more difficult due to the working coditions in tunnel, the space problem and the efficiency of the equipment under hazardous condi«• tions. Geology adds to these constraints. Time factor assumes great importance in .construction of long tunnels in power projects, and it has been found that this component usually is a critical activity hampering the commissioning. .. Simulation is a too], through which we can plan tunnel construction more precisely as it tries to imitate reality. . In the s dissertation simulation models have been built to study the behaviour of the construction schedule undo s varying condi tionsA Excavation, and concreting can be done independently or concurrently and a study has been made as to how the total time of tunnel construction is affected by adopting these methods. In the course of the study .the planning for optimal combination of equipment also comes into play. The equipment required for least time as well as effect of equipment size on the tunnel construction time has also been studied. The whcl© study has been based on data collected from a actual tunnelling project and actual conditions in a tunnel,and hence the results are bound to be helpful in construction planning of similar sized tunnels.