本研究之目的在於防止管溝崩塌時造成災害，特別是要設計出擋土防護裝置，以保障勞工安全。計劃的第一步是依據職業災害報告，整理災害發生的情況，發現許多災害係發生在2或3公尺的溝渠，接著到工地從事現場訪談，收集到許多寶貴的經驗。然後從事擋土防護裝置之設計，提出了五種設計構想，並探討實際可行性。這份論文亦針對這些設計構想從事評估，並且調查目前國內專利情況，以了解未來製作及研發方向，然後針對以上所述之一設計構想，收集目前管構施工作業程序，探討使用保護裝置對施工的影響。最後，本研究也擬出此裝置之作業程序與使用限制。 The purpose of this research is to provide protection for workers working in the trench from being buried during trench cave-in. Shielding devices are to be designed for this purpose. The first step of this research is to study previous reports. We understood from these reports that many incidents were for trenches of depth 2m to 3m. We then visited many construction sites, interviewed with many workers. Very useful information were collected. Five different designs of shielding device were proposed in this report. In this paper, evaluation for each design is given. Domestic and international patents are also studied. Operation procedures and limitations of one design are proposed.