Geologic selection methodology for transportation corridor routing

Abstract

A lack of planning techniques and processes on long, linear, cut and cover-tunneling route transportation systems has resulted because of the advancement of transportation systems into underground corridors. The proposed methodology is tested in Texas on a shallow cut and cover-tunneling corridor for a high-speed freight transportation system. Different surface (landform, geology, soils) and subsurface (hydrogeology, soil and rock properties) properties, as well as waste disposal and similar conditions along the corridor influence this methodology. Because this long distance cut and cover route is a new transportation concept, a new methodology must be developed to provide preliminary route selection information. The objective of this project was to develop a new methodology for transportation planning so that it can be used for transportation projects in the future. The technique that performs a preliminary investigation of an area is completed by studying the aspects of the environment and determining any fatal flaws along the corridor. Then a preliminary ranking system and evaluation can be conducted using other site evaluation techniques that aid in conducting a comparison of area and the selection of areas that appear to be most favorable for the facility. This methodology was applied to an area, roughly 400 miles long, along I-35 between Laredo and Dallas, Texas, where the Texas Transportation Institute, TTI, is considering a shallow cut and cover-tunnel corridor for a high-speed freight transportation system. The test successfully completed each objective and confirmed that this new methodology works. The results indicate that three main parameters, topography, demography, and rock mass, have the greatest impact on the underground corridor in this project.