对水上作业天标准的新认识与工程实践

New Understandings of Criteria for Working Days at Sea and Engineering Practice

针对长江口深水航道治理工程历时长、工程涉及的水域范围广阔、整个施工范围内的自然条件特别是影响水上作业的风、浪、流、水深差别甚大、大型专用作业船舶众多的特点,分析了影响水上作业天的主要因素,明确提出了应分工序、分作业船确定两类不同的气、海象标准,即生存标准和作业标准。基于对影响水上实际作业天数因素的新认识,论述了提高水上有效作业天的工程措施。通过两艘典型施工船舶的可作业天和有效作业天统计分析结果可以看出,在长江口二期工程中,由于确立了“作业标准”和“生存标准”及争取“有效作业天”的意识,各施工单位注意了对各种有利因素的充分挖掘和利用,大型专用施工船的可作业天可提高到19～26 d/月,即使受到各种非正常因素一定影响,实际用于水上施工的有效作业天仍达到了13～15 d/月。

In view of the long construction period of Yangtze Estuary Deepwater Channel Regulation Project, vast water area covered, great difference of the natural conditions within the whole working range, especially the wind, wave, current and water depth which affect the operations at sea, as well as the large amount of working vessels on the site, this paper analyzes major factors affecting the days for working at sea, and proposes two different climatic and oceanic criteria to be determined according to the working procedures and the types of working vessels, i.e. the survival criterion and the working criterion. Based on the new understandings of the factors affecting the actual number of working days, the engineering measures for increasing the days for effective working are expounded. The results of statistical analyses of the workable days and effective working days of two typical working vessels reveal that during implementation of the 2nd phase of Yangtze Estuary Deepwater Channel Regulation Project, since all the construction units involved in the project paid attention to full tapping and utilization of various favorable factors according to the ＂working criterion＂ and ＂survival criterion＂ and due to their consciousness in striving for the ＂effective working days＂ . As a result, the number of workable days of the working vessels could be increased to 19 - 26 days per month and the effective working days at sea reached 13 - 15 days per month even though the operations at sea were affected to some extent by various abnormal factors.