IMPACTS OF GEOTECHNICAL ASPECTS IN TUNNELING DESIGN AND CONSTRUCTION

Abstract

In tunneling project, different type of methods is conducted to do the project. Knowing geotechnical aspects of tunnel project is unavoidable and crucial in early stage of project especially before contract to have efficient and more accurate design and prevent cost overruns, reduce bid price and reduce project risks. However, all that geotechnical information should be based on standard guidelines such as Geotechnical Baseline Report (GBR) to help owner how to provide those geotechnical data in bid contract and use it as a guideline in contract to prevent future claim or disputes. The main objective of this thesis is about to illustrate the importance of geotechnical investigation in early stage of tunnel project and measure the impact of geotechnical information on project from different perspective. To conduct this research, first, a comprehensive literature search was conducted. Second, a case study was used from real project to demonstrate what type of geotechnical investigation was conducted for that project before and after contract. In addition, qualitative analysis has been performed to compare case study project’s contract with GBR-ASCE standard to determine deficiencies of the contract and project. In continue, a general questionnaire was prepared to clarify issues and important factors of the project. It was answered by owner, consulting engineer, contractor’s representatives. The main technical and geotechnical challenging and risk factors were identified and their effect was analyzed and discussed. Finally, Numerical modelling utilizing finite element method by PLAXIS was conducted to determine the impact of lack of appropriate geotechnical investigation on increase of cost of project and the risk of owner by increasing bid price and consequently total cost of project.