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Speed dispersion is recommended to proactively assess road safety because (1) it provides consistent risk evaluation with microscopic potential risks and (2) it makes data collection easier.

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Single-lane modern roundabouts are one of the most important intersection types in suburbs of Australia. It is therefore important to estimate their entry capacities. In this case study, we firstly propose an analytical model based on the gap acceptance theory by incorporating the effects of the exiting vehicles. It then proceeds to carry out a scenario analysis to assess the effects of the exiting indicators. This is followed by the discussions of the applicability of the proposed model. The results show that the transport authorities need to strictly enforce the use of indicators before exiting in order to achieve higher capacity.

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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.

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Tunnelling-induced ground surface settlement prediction still adopts empirical and analytical approaches; thus a step further in using a practical numerical analysis is now a challenging task. Because the deformation during tunnelling is a three-dimensional problem, several features were incorporated in two-dimensional analyses to capture aspects that are important in governing behaviour in the missing third dimension. This paper aims to present simplified methods for ground settlement computation of tunnelling works using the PLAXIS finite-element programme. Three simplified methods – contraction ratio, stress reduction and modified grout pressure – were considered in this study. Practical application requires correlations among these three methods. Such correlations among the three methods are proposed in this study and can be used in geotechnical practice. The results were based on a series of finite-element analyses of the Blue Line Bangkok Mass Rapid Transit tunnels. The geotechnical parameters were selected based on soil investigation reports carried out for construction purposes. The soil constitutive model adopted herein was the hardening soil model on soft and stiff clays. All the finite-element simulations were compared with the measured field deformations. Therefore, the analysis results can be considered as a Class-C prediction (back-analysis).