潛盾機在大卵礫石層之掘進中，因大卵礫石切削不易、出碴困難及開挖面土艙壓力控制不易處理，致使潛盾機在卵礫石層之潛盾隧道施工中，常發生受困及阻礙影響。 本文針對卵礫石層中之潛盾隧道施工案例，並參考各工程案例與潛盾隧道施工相關的工程參數，如地下水位、卵礫石含量、卵礫石最大粒徑等地質條件，以及潛盾機外徑、覆土深度等工程基本資料，藉以瞭解潛盾之施作方法，並針對潛盾機於卵礫石層中之掘進過程，由於卵礫石地層之不確定性，造成潛盾機遭遇障礙以致潛盾機前進受困停滯影響，並以實際施工案例，探討潛盾工法於卵礫石層之施工困難點，及現場困難問題之解決對策等。所得之心得期能提供後續設計與施工之參考。 ;When a shield tunneling machine is used to excavate tunnel in large gravel layer, it may have difficulties in cutting large gravel, mucking or controlling the pressure of the soil tank for the excavation surface. As a result, the shield tunneling machine is often trapped and the shield tunneling in gravel layer is hindered. This paper studies cases of shield tunneling constructions in gravel layers and refers to engineering parameters related to each of these engineering projects and shield tunneling constructions, that is, geological conditions, such as underground water level, gravel content and maximum particle size of gravel, and some other basic engineering data, such as the outer diameter of shield machine and the depth of the covering of soil, so that we may understand how shield tunneling is implemented. Furthermore, this paper examines the situations where a shield machine encounters obstacles and is thus trapped or stopped in the process of excavating a gravel stratum because of the uncertainty of the gravel stratum. Then, by reference to these real cases of construction, this paper discussed the difficulties that the shield tunneling method may face when it is applied to a gravel layer as well as the countermeasures to solve problems on site. It is hoped that what is learned from this study may be referred to in future design and construction.
