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Approach of the performance design of a reclaimed land in consideration of the reliability of permeability Hirofumi NISHIDA, Takeshi NAGAE, Takeshi SATOH Long-term differential settlement of soil structures causes the problem of maintenance. Recently, the reduction of cost for construction is required. Thus the method of life cycle performance design that can appmpriately evaluate the life cycle cost is requested. In this paper, the approach of the performance design for a reclaimed land by using the soil/water coupling elasto-viscoplastic finite element method is discussed. The input parameters for this analysis are identified by the information of the soil tests. The results of the tests have some difference, so that these parameters are usually identified as mean value. Particularly, the coefficient of permeability is the most difficult to. In this paper, the influence of the coefficient of permeability on the predicted LCC is examined, and the performance design for a reclaimed land in consideration of the reliability of the permeability is also discussed.

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Static and dynamic centrifuge model tests, conducted to investigate mechanical behavior of buried pipes installed in sloping-sided ditches, revealed that the safety of the pipe is critical under vehicle loading applied in the static tests rather than seismic loading applied in the dynamic tests. The static tests were analyzed by using FEM, in which the soil and pipe were assumed to be linear elastic. Small frictional resistance was allowed at the interface between the pipe and the soil by introducing joint elements. Separation, slip failure, and frictional resistance were also allowed at ditch walls by introducing similar joint elements. The analysis generated results that conformed well to the test results, while the current design standards tend to underestimate the safety of the pipes. Thus, design charts for predicting the vertical deflections and the maximum bending moments of the pipes that are buried in sloping-sided ditches with different inclinations of the ditch walls were constructed by using the FEM. A thorough examination showed that the charts can be applied reasonably to any pipe (regardless of different weights, dimensions and materials), any backfill soil (regardless of different soil types, elastic coefficients and weights), and any cover height, leading to the conclusion that the charts can be used instead of the problematical current design methods.