Optimization for Excavation Spacing of Two Lower Tunnel Tubes at Overlapped Section with a Minimum Clear Distance
(1 College of Civil Engineering and Architecture, Shandong University of Science and Technology Qingdao, Shandong 266590; 2 No.1Engineering Co., Ltd. of China Railway Construction 17 Bureau Group Ltd., Taiyuan 030032; 3 Ji′nan Rail Transit Group Co., Ltd.,Jinan 250101)
Abstract：
Aimed at addressing the complex force conditions, challenges to blasting and support in overlapping tun? nels with a minimum clear distance, a numerical simulation is carried out for lower tunnel tubes regarding five kinds of excavation spacing. The distribution features of the surface and crown settlements of two lower tunnel tubes for different excavation spacings are analyzed based on the Zaoshanlu-Lichun running tunnel project of the Qingdao metro, and the stability of the rock mass and construction costs for different excavation spacings are studied by numerical calculations and theoretical analysis. The results show that the surface settlement, vault settlement and volume of the plastic zone will decrease gradually with an increase of the excavation space between the parallel tunnel tubes, along with the extension of construction period and the increasing of expenses; so a reasonable excavation spacing between the left and right tube is 25~35 m determined by the multi-index comprehensive assessment meth? od.
.Optimization for Excavation Spacing of Two Lower Tunnel Tubes at Overlapped Section with a Minimum Clear Distance[J] MODERN TUNNELLING TECHNOLOGY, 2017,V54(5): 200-208
2017, Vol. 54 