In this study, the reclaimed soils in the Yunlin area of west Taiwan are adopted as test samples. The specimens were prepared by moist tamping at different relative densities and fines contents. Triaxial liquefaction tests were performed to evaluate the liquefaction strength and liquefaction-induced settlement. The test results show that the liquefaction strength of reclaimed soil increases as the relative density increases. In addition, under constant relative density, the liquefaction strength decreases as the fines content increases. Based on the test results and one-dimensional consolidation theory, the volumetric strain and settlement can be evaluated by dry density and fines content of the reclaimed soil. The results show that the settlement ratio decreases as the relative density increases. The figures and results can be references for the evaluation of liquefaction strength and liquefaction-induced settlement. The results are useful for liquefaction strength and settlement analysis for planning, design, and related research on land reclamation engineering.Key words: reclaimed soil, liquefaction resistance, fines content, settlement.

Abstract:In this study, the geophysical properties of the landslide-prone catchment of the Gaoping River in Taiwan were investigated using zones based on landslide history in conjunction with landslide analysis using a deterministic approach based on the TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability) model. Typhoon Morakot in 2009 was selected as a simulation scenario to calibrate the combination of geophysical parameters in each zone before analyzing changes in the factor of safety (FS). Considering the amount of response time required for typhoons, suitable FS thresholds for landslide warnings are proposed for each town in the catchment area. Typhoon Fanapi of 2010 was used as a test scenario to verify the applicability of the FS as well as the efficacy of the cumulative rainfall thresholds derived in this study. Finally, the amount of response time provided by the FS thresholds in cases of yellow and red alerts was determined. All five of the landslide events reported by the Soil and Water Conservation Bureau were listed among the unstable sites identified in the proposed model, thereby demonstrating its effectiveness and accuracy in determining unstable areas and areas that require evacuation. These cumulative rainfall thresholds provide a valuable reference to guide disaster prevention authorities in the issuance of yellow and red alerts with the ability to reduce losses and save lives.

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The hydraulic placement of sand fill is one of the most important methods of land reclamation. During the reclamation process, losses of fines in sand are induced by the transportation of soil which affects the dynamic properties of the soil materials. In this study, the reclaimed soil in the Yunlin area of Taiwan is adopted as the test material. Different fines contents, different relative densities, and initial stress ratio were taken as test conditions. Resonant column tests were performed to evaluate the shear modulus and damping ratio of the reclaimed soil under initial shear stress. The results show that the maximum shear modulus decreases as the fines content increases. The influences of initial shear stress are discussed. A prediction method for maximum shear modulus under different fines content and initial shear stress is proposed based on empirical equations obtained. The results can be helpful for land reclamation design and assessment.

This paper presents a pioneering study on numerical modeling of load bearing characteristics of the jacket foundation pile for offshore wind turbines on the west coast of Taiwan. Because Taiwan is located in an earthquake prone area, there is significant interest in improving the prediction of the behavior of wind turbine jacket foundations subjected to seismic loading. Investigation of the bearing capacity of the jacket foundation pile for the offshore wind farm using effective stress analysis, with consideration of pore pressure generation and soil/liquid coupled analysis, was conducted. A new procedure to evaluate the design of offshore wind turbine foundation piles in the sand and clay inter-layered soil was also proposed. Static and dynamic analyses of bearing capacity of the jacket foundation pile were conducted. Results obtained demonstrate that the design process for the jacket foundation pile proposed in this study can properly reflect the interaction behavior of the foundation and the soil. In addition, the pore pressure generation model can be used to simulate soil liquefaction. The proposed method is also very useful in the evaluation of the design capabilities of offshore wind turbine jacket foundations.