No abstract

This paper covers the blast-resistant analysis for a tunnel passing beneath Taipei Shongsan airport. It briefly discusses the overall analysis process to obtain the maximum lining thrust caused by a bomb explosion for use in the structural lining design. Because there have not been any established common standards or practices governing the design of such a structure, a series of parametric studies have been carried out in order to evaluate the significance and sensitivity of several parameters on the lining thrust. The parameters evaluated are: intensity of blast loading, size of crater, dynamic undrained shear strength, dynamic Young's modulus, and soil-damping ratio. It was concluded that a designer should adopt dynamic soil parameters, obtained from good ground investigation and soil testing, as favorable dynamic soil properties can result in a more economical analysis. For parameters (e.g. bomb type) that are beyond the control of the designer, an additional protective layer over the tunnel structure may be considered in order to minimize the impact of the explosion, instead of designing a more costly rigid structure.

The successful application of instrumented borehole drilling techniques in offshore exploration has encouraged its further use onshore as a ground investigation tool. The drilling of holes for grouting tubes creates the potential for obtaining supplementary ground information, which may be valuable to the succeeding tunnel construction. The instrumented drilling system was therefore investigated to determine its power to discriminate between ground strata. The configuration of the drilling system in terms of plant, equipment, and testing procedures was standardized and applied at a site in Kennington Park in London. The general characteristics of the measured drilling parameters are given and qualitative and quantitative methods of interpreting the drilling parameters are demonstrated. The possible soil-machine interactions that are responsible for the measured drilling characteristics are examined. A new method of data interpretation is proposed for identifying soil formation changes. Previously published correlations and analyses of drilling were examined and tested by comparing the trend-lines of drilling data in London clay against known undrained strength data. The degree of correlation was found to be limited.

No abstract