MANAGING GEOTECHNICAL RISK IN RAILROAD DESIGN AND CONSTRUCTION

摘要

In the early stages of railroad engineering and construction, railroads were constructed on "good ground" (i.e., firm and dry ground). However, the amount of good ground available for railroad expansion is increasingly difficult to find, leaving much of recent railroad expansion to "bad ground" (i.e., soft and wet ground), which can increase geotechnical risk on a construction project. The railroad industry's view of geotechnical risk has changed little. Borings are still generally spaced at half-mile intervals, and there is pressure on geotechnical engineers to help win projects by reducing geotechnical scope and budgets. Geotechnical engineers often work as subconsultants to a prime design consultant, who may not appreciate the increased risk associated with reduced geotechnical scope and budget because they are trying to win a low-bid competition. Railroads are increasingly trying to reduce capital and maintenance expenses, putting additional pressure on design and construction projects. Geotechnical risk is often the biggest source of cost and schedule increases during construction; however, geotechnical risk is frequently overlooked, resulting in significant changes that affect the original design, construction cost and schedule. This paper discusses the management of geotechnical risk during design and construction of a few railroad construction projects, and summarizes the design changes made during construction and the effects of these changes on cost and schedule, many of which could have been avoided with proper geotechnical risk management. The paper closes with recommendations for geotechnical risk assessment and management for railroad projects, and the benefits to the railroad industry.