Improving Productivity Of Tunnel Boring Machines

Abstract

Tunneling with tunnel boring machines (TBMs) is one of the most mechanized and sophisticated processes within the construction industry. However, there are risks when venturing down several hundred feet where the conditions cannot be accurately determined in advance. Months and years of planning, engineering, profiling, researching, and scheduling go into a typical tunneling project before any ground breaking event. This thesis will discuss in detail the growing technologies of the tunneling process using tunnel boring machines (TBM). First, some background information on tunneling and the use of a TBM will be provided to introduce the process and the industry being discussed. A tunnel boring machine is unique to each project based on the ground conditions that will be encountered, the diameter and length of the tunnel, as well as several other technical and dynamic factors. After the introduction, the thesis will examine a case study of an ongoing project, the Jollyville Transmission Main for the Water Treatment Plant #4 in Austin, Texas. Particularly, one of the TBMs being used will be studied in order to maximize production. The details of this project will provide an opportunity to discuss production improvements, scheduling impacts, and project costs. Different methods and their effect on the overall project outcome will be compared. The case study information will be compared with literature, as well as on-the-job information gained from discussions with the project manager, superintendents, and other on-site personnel. This research concludes that given certain circumstances, the use of a continuous conveyor, rather than the muck car/rail method, has potential for a quicker completion schedule and a greater profit for the contractor.