| dc.description.abstract | 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.
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