ABSTRACT:

A vast amount of various geotechnical data is obtained during the tunneling process. Use of this dat in design and construction can be enhanced by visualization so that the geological data can be seen as it would be seen in the uncerground excavation, either before or during excavation The Adaptive Real-Time Geological Mapping Analysis of Underground Space (AMADEUS) project involves research on how to utilize new geologic information that is captured during tunnel excavation using laser scanning devices, digital cameras, tomography, and other sampling methods. This data is used to build joint network models and numerical models and provide meaningful interactive visualization for engineers. Visualization from within a virtual tunnel, the use of virtual envireonments in this process, and in particular, a novel graphics algorithm used to helop construct virtual excavations in a virtual environment (VE).

INTRODUCTION

Modern underground construction involves the utilization of many principles and technologies to optimize the design for the encountered natural surrounding conditions. Very often empiricism plays a significant role in the decision processes. In addition, the wealth and type of data that can be obtained a the preliminary as well as the actual construction phases of a project can assist the efficiency and design optimization only if these are organized well and accessed easily at any time. Such data include geologic and geotechnical information for the surrounding ground, data from monitoring the behavior of the ground. Today an improvement of the monitoring equipment in terms of quality, robustness, automated technologies and a gradual reduction in cost makes them being used more often and more systematic for QA/QC purposes, not only in soft ground tunneling but also when tunneling through jointed rock masses. This creates a need for a management and processing system which stores, handles and processes information obtained from the site. This issue is addressed by the AMADEUS project. Part of the project aims in generating data using laser scanning, photogrammetry, and tomography techniques. Using this data, fractures and can be identified and fed into stochastic fracture models and rock mass quality assessment, which can then be used to develop numerical models for tunnel behavior prediction and back-analysis.

In a tunneling excavation that follows the Observational Method, new fracture, rock mass quality, and monitoring data is continually being obtained. The challenge is to be able to utilize this data to enhance the excavation and design. The use of this data depends on how quickly and efficiently the data can be processed and analyzed. 3D visualization, such as VE, is a valuable aid in designer/engineer?work site interaction, that can improve efficiency and quality of tunneling excavation. 3D visualization has been utilized in tunneling, mining, and other excavation applications [1, 2, 3].

This paper briefly describes fracture modeling and numerical modeling and their application to VE for the AMADEUS project. The paper describes the software program that was written to help augment pre-existing engineering programs and what tools were used to build it. In particular a novel computer graphics algorithm designed for the study of fractures during tunneling is presented. This algorithm allows engineers to actually walk inside of a tunnel in a VE before excavation is completed, or the next step of excavation is started. This paper will also discuss the visualization techniques that have been applied in the AMADEUS project. These applications include viewing fracture models and numerical models and performing virtual excavations of fracture models in CAVE[4]

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