UBC Theses and Dissertations
Critical assessment of the canlex blast experiment to facilitate a development of an in-situ liquefaction methodology using explosives Pathirage, Kapila S.
In current engineering practice, the liquefaction susceptibility of soil is assessed by in-situ testing or by laboratory testing. The in-situ testing approach is based on field performance correlation approach and it is good for sandy soils, but becomes difficult to apply in soils such as gravels, silts and clays. In laboratory conditions, the cyclic loading tests could indicate inaccurate results unless those have been performed on absolutely undisturbed samples. The research in this thesis is a part of larger investigation, which is intended to explore the potential for evaluating liquefaction susceptibility in-situ by blasting. The main advantage of such a methodology is that the liquefaction resistance of the ground is evaluated under its existing stresses and ground water conditions. The major part of this research is a critical assessment of a field trial blast test, which was carried out during the Canadian Liquefaction Experiment (CANLEX) in Alberta. This includes the evaluation of measuring instruments used in the test, sampling rate and evaluation of measured data. In addition, this research investigates the induced wave patterns due to an explosion and the near field blast effects and the far field blast effects. Also, the research evaluates the possibilities of simulating earthquake like ground motions using explosives. The thesis establishes empirical relationships for liquefaction evaluation in loose saturated sandy soils. The state of art to establish these relationships is discussed. A comparison of these relationships with those proposed by other authors is also presented. In addition, the thesis discusses observed inadequacies of the CANLEX blast test to help in planning and conducting blast tests in the future.
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