沉箱施工潛在危害探討與改善對策之研究

A Study on the Potential Hazards and Improvement Strategies of Caisson Construction

沉箱因工程用途不同與施工環境條件差異，工法選擇也有不同。近年來，沉箱作業期間發生的工安事故中，往往因作業安全管理疏失，造成人員墜落與溺水危害風險最高。為避免類似沉箱作業危害發生，本研究透過沉箱職災案例分析，及實務訪視與訪談，整理出沉箱施工特有災害事故成因及安全管理重點，以提供設計規劃階段至施工階段參考。
研究成果發現：1.自重沉箱用途已被全套管基樁取代，目前僅少數作為井基提供橋梁基礎結構，主要特別危害以異常出水與異常沉降為主；2.壓入沉箱為目前國內最多採用，施工安全性高，對施工作業環境限制較小，主要特別危害以錨定鬆脫造成人員墜落、物體飛落為主；3.壓氣沉箱因作業成本高，施工難度大，且人員於壓氣環境作業危害高，除非特殊必要，甚少被採用；4.浮體沉箱作業流程趨於標準化，於沉箱構築之作業安全性高。但於沉箱儲存、拖運及安置過程受天候環境影響大，必須確實掌握以確保人員作業安全，主要特別危害以沉箱傾斜造成起浮時人員溺水危害為主。
依據研究成果因應工程作業特性所可能造成的災害原因與改善對象，未來將持續就工法技術評估及施工風險危害鑑別內容加以探討。期能透過沉箱施工安全管理工作的落實，有效控制與減少不必要的危害造成人員傷亡，以提升工地安全。

Caisson construction methods vary according to engineering functions and site conditions. In Taiwan, press-in and floating caissons are predominantly used, while gravity and pneumatic caissons are now rarely adopted. Recent occupational accidents during caisson operations have largely resulted from inadequate safety management, with falls and drowning constituting the primary hazards. This study investigates accident causes and safety management deficiencies through an analysis of caisson-related accident cases, supported by field observations and practitioner interviews.
This study investigates the causes of caisson-related occupational accidents and associated safety management issues through case analyses, field observations, and expert interviews. The findings reveal that: (1) Gravity caissons have largely been replaced by full-casing bored piles, with limited applications in well foundations for bridge structures, where abnormal water inflow and uneven settlement are the main hazards; (2) Pressed-in caissons are widely adopted due to their high construction safety and minimal environmental limitations, yet they remain susceptible to anchor loosening, leading to falls and falling-object incidents; (3) Pneumatic caissons are rarely used owing to high construction costs, operational complexity, and significant health risks associated with pressurized environments; and (4) Floating caisson operations have become more standardized and generally exhibit high safety performance, though the storage, towing, and placement phases are highly affected by weather conditions, with caisson tilting posing a major drowning risk.
Based on these findings, this research emphasizes the importance of continuous assessment of construction techniques and hazard identification in response to engineering-specific risks. The study further suggests that the implementation of effective safety management systems in caisson construction can significantly mitigate unnecessary hazards, reduce occupational injuries and fatalities, and ultimately enhance construction site safety performance.