阿拉斯加北极地区的工程设计和施工经验及教训

Experiences and Lessons Learned in the Engineering Design and Construction in the Alaska Arctic

阿拉斯加北极地区位于布鲁克斯山以北, 白令海峡以东的北坡地区, 属北极海洋性气候区. 区内寒冷(-10^-6 ℃)、连续多年冻土厚度多在200~300 m, 局部达700 m. 地表湖塘和冰楔多边形广泛分布. 阿拉斯加北极地区的工程建筑活动主要为海军部和商业石油勘探、开发和运输服务. 从 20 世纪40年代以来, 尽管有不少的曲折和教训, 但成功和可以借鉴的经验很多. 最成功的例子当数普如道湾油气田开发、阿里亚斯卡输油管道工程及其相应的环境保护措施. 工程师为了成功和经济地在北极地区修筑和运行工程设施, 必须从“冷”处着想, 并付诸计划和行动. 设计和施工的工程师必须保持实事求是、不断创新精神, 而不拘泥于中纬度地区的教育、培训, 或行业传统. 从工程勘察、设计到施工阶段, 工程师和从事环境研究的科学家必须密切合作. 工程师需要知道环境参数, 制约因素和可利用的机会; 环境科学家需要知道工程师的施工设计和问题, 理解工程限制条件、设备工作能力, 以及备选方案的经济学问题. 这些相互理解只能在密切合作中形成, 并能创造工程经济效益和奇迹.

The Alaska Arctic is located at north of the Brooks Range and from the Bering Sea to the Canadian border, with an arctic marine climate. Cold and continuous permafrost with thicknesses from 200 to 300 m, sometimes to 700 m, are widespread. The most prominent surface manifestations of the underlying permafrost include numerous small lakes and ponds, ice-wedge polygons and tundra wetlands on the arctic coastal plain. The engineering construction in the Alaska Arctic was mainly driven by naval and commercial exploration, development and transportation of crude oil and natural gas from the Prudhoe Bay, Cape Simpson, Umiat and Barrow areas, and some military operations, such as the Distant Early Warning Line radar stations since 1940s. There are many experiences, lessons learned and body of knowledge obtained during all these engineering construction periods. The most successful engineering feats include the exploration and later development of the Prudhoe Bay oil/gas field, Alyeska Hot Oil Pipeline, and environmental protection regulations during most of these engineering activities, which resulted only minor impacts considering so many mega-projects were undertaken with very limited knowledge of permafrost terrain in advance. In order to successfully and economically engineer for construction and operations in the arctic, it is necessary to think 'cold', and to plan and act accordingly. The construction engineer must be innovative and not be bound by mid-latitude mind-settings gained from education, training or conventional wisdom. The engineer and the environmental scientist must work as a team during the initial field survey, during the design phase, and during the actual field construction. The engineer needs to know the environmental parameters, constraints and potential opportunities. The environmental scientist needs to know the engineer's construction design and problems, and understand the engineering constraints, equipment capabilities, and the economics of potential alternative courses of action. These understandings cannot be acquired working alone, then trying to coordinate results after each has invested time and effort and developed plans and positions which they are reluctant to modify.