砂性海床管道承载能力与入泥深度上限分析

Upper Bound Analysis of Bearing Capacity and Penetration Depth of Shallow Buried Pipeline on Seabed

本文基于刚塑性极限分析理论,按照Hill塑性破坏模式,构建了砂性海床土体运动许可速度场。对饱和不排水砂性海床上浅埋圆形管道的极限承载能力以及管道的入泥深度进行了理论推导,给出了浅埋圆形管道承载能力与入泥深度的上限解答。同时,为了验证本文给出的承载能力和入泥深度上限解答的合理性,将计算结果与国内外规范中常用的Terzaghi等计算公式进行了对比分析。对比结果证实了本文上限解答与失稳模式较为合理。

An ecosystem health assessment methodology based on analytic hierarchy process and synthetic index method was established for assessing health level of artificial reef areas. Based on the biological resource and environment survey from Sept. 2012 to July 2013 in Xigang, it was shown that both artificial reef and control areas were at healthy level in spring, summer and autumn, and at sub healthy level in winter. The ecosystem health index of artificial reef area was significantly higher than that of control area （P=0 009）. The ecosystem health index changed in different seasons, summer, autumn, spring, then winter constitute the order from the highest to the lowest. According to the comprehensive analysis, the ecosystem health in the artificial reef area was much more stable than that of control area. Long term monitoring and surveying were needed in these areas. The research results were significantly referable to the management and protection of artificial reef areas.