以DELPHI法探討合理工期之研究─以大型鐵路工程為例

Abstract

隨著國民所得不斷增加，大眾對交通運輸之需求日益殷切，政府雖極力構建公路網，仍不敷汽機車數量的成長，使得公路運輸日趨擁塞。鐵路運輸因具運輸量大、時間準確、安全等優點，政府乃希望藉由改善鐵路軟硬體設施、設備及營運措施，提高鐵路運輸的質與量，期吸引民眾搭乘，達成抑制汽機車數量並促進經濟再成長，因此成為政府近來推動公共建設的重要環節。 依文獻工期之估算方法概分三種即：排程細估法、統計計量法及經驗巨觀估算法，其中排程細估法係依工程作業要徑上實體設施設備之要徑作業規模乘其單位工時累計得到總工期，本法因需有詳盡（即設計完成後）之細項作業及數量，在施工階段纔得以使用。而統計計量法則由大量已完成之詳盡工程文獻整理分類而得之資料，藉由統計計量得到工期估算式，因此常每隔一段時間即需耗費大量人力整理新資料，以更新原估算式。 至於經驗巨觀估算法因使用簡便，在工務及審議機關廣泛使用，以往其工期均倚由資深工程司依其經驗估算，個人主觀意識濃厚，且經驗傳承不易，因此本文希望藉由DELPHI法綜合多數經驗豐富專家意見，獲得影響工期之確定與不確定因素及其對應之參數，以建構較客觀之經驗估算式，期供工程審議機關使用。

While the general public demands more on traffic and transportation thanks to the ever increasing national income, the Government though has its full gears on improving the highway network, highway transportation gets serious congestion by day in failing to cope with the growth of the numbers of automobile and motorcycle. Whereas the railway transportation for providing safe, and massive transportation capacity on schedule, the government hopes to attract the people to take train by improving hardware and software facilities, equipment and operation measures to upgrade railway transportation both in quality and quantity; to inhibit the growing numbers of automobile and motorcycle; and to promote economic growth once again. Consequently, railway transportation has become one of the major links in pushing forward the public reconstruction by the Government.According to documentary study, three methods, respectively, the Scheduling Technique, the Statistic Method and the Macroscopic Expert-estimating Method, are usually applied in estimating the length of work schedule. Wherein, the Scheduling Technique Method solves the total length of work schedule by multiplying the operational scale of key-route of the physical facilities and equipment on the key-route of the project operation by the unit work hour; however, it takes detailed itemized operation and quantity (that is, upon the completion of the design) for this Method to become applicable upon entering the phase of construction. As for the Statistic Method, data are available after lengthy assortment and categorization of massive related documentation that already have been published to solve the work schedule estimate formula, meaning massive manpower is required to be consumed periodically to recompile the data to update the estimate formula.The Macroscopic Expert-estimating Method for being comparatively easier to apply is popularly used among the work engineering and advisory institutes. In the past, expert-estimating has been always done by some senior engineers, meaning a very strong subjective sentiment is involved and it has never been easy to pass down the expert experience. Therefore, this study attempts to generalize opinions from the majority of experts with proved expertise by using the DELPHI Method to identify those certain and uncertain factors that affect the work schedule as well as to find out their relative parameters to recommend more objective expert-estimating formula for the reference by the work advisory institutes.