| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程技術學系 === 86 === A full scale field test and a 2-D laboratory model test were adopted to study the compaction grouting induced soil and strength increase for soil around the grout bulb and the ground surface heave - resettlement. A predictive model for evaluating the compaction grouting induced soil strength improvement is proposed based on the test laboratory results. The full scale test indicates that the amount of surface heave is related to the radius of grout bulb (r) and the distance from the injecting point(h). For h = 6.5 r to 20 r, the ground heaves is not much affected by the increase in grout volume nor by the distance from the injecting point. In comparison, for h < 6.5 r, the surface heave becomes larger and the amount of heave increases more significantly as it gets closer to the injection point. When the excess pore-water pressure dissipates, about 1/4 to 1/5 of the ground heave will settle back in a time period of 40 days. The laboratory model test indicates that degree of strength improvement tends to decrease with the distance from the injection point. At a distance more than five to six times the grout bulb diameter, no obvious increase in soil strength was observed. The softer clay, the higher degree of strength improvement can be achieved. The predictive model show that the soil strength improved around the compaction grout bulb increases with the decreasing distance, the increasing void ratio, the decreasing compression index, as well as the decreasing material parameter. The amount of strength increase can be satisfactorily predicted by the proposed model.
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