Abstract: This paper is base on the statistical analysis result of construction rate of shield tunneling in Tao Yuan Airport MRT CU02A Section. And then with aim at the design consideration of shield machine which will excavate in gravel layer, the paper considers whether enabling the shield machine to excavate efficiently in the gravel layer. The measures to cope with various problems arising during the process of actual construction, the measures whether could deal with these problems exactly. Total 8 sets of 6.24 mdiameter earth pressure balanced type shield machines were adopted in the CU02A. Through statistical analysis of the result of the construction rate of 10 shield tunnels by 8 sets of shield machines, it is suggested that it may be appropriate to evaluate the construction rate of the shield tunneling in the gravel layer according to tunneling 2 m/d at the initial stage and 4.5 m/d at the main stage of the shield tunneling construction. It is found and displayed that the rate of construction at the following construction areas is better than at the earlier construction areas and the coping measures put forward for the problems arising in the earlier construction were well proved during the later construction when the construction rates of shield tunneling construction at five areas are reviewed respectively. Hereby, this paper reviews the rate of the total construction and coping measures for the arisen problems and give feedbacks to the initial design considerations in the hope of providing references for the future construction design considerations and planning.

Key words: shield machine, gravel layer, construction rate