Abstract:

Taking the largediameter metro shield tunnel on the south extension line of Guangzhou Metro Line No. 4 for example, the external load and internal force response principle of lining structure in operation phase are obtained by field test of external load and reinforced bar stress of lining structure monitored by sensors of waterearth pressure gauge and reinforced bar stress gauge. The rationality of the calculation model of lining structure is illustrated by comparison between the theoretical value of the model and the field test results. The study results show that: 1） The total pressure of soil and water on top of tunnel coincides with the weight of overlying soil column. 2） The total pressure of soil and water at the bottom of the tunnel is small at middle section and those are large on both end; therefore soil springs can be arranged in the lower half circle of the lining structure to simulate the actual stress in the calculation model. 

Key words: soft soil, largediameter metro shield tunnel, external load of lining structure, internal force response, field test