Abstract

Traffic jam and congestion in urban areas has caused the need to improve the utility ofunderground space. In response, research on underground structures is increasinglybeing conducted. Notably, a double-deck tunnel is one of the most widely used of allthose underground structures. This double-deck tunnel is separated by the middle slabinto the upper and lower roadways. Both vehicle load and earthquake load cause themiddle slab to exhibit dynamic behavior. Earthquake-related response characteristics,in particular, are highly complex and difficult to interpret in a theoretical context, andthus experimental research is required. The aim of the present study is to assess thestability of a double-deck tunnel’s middle slab of the Collapse Prevention Level andSeismic Category 1 with regard to the presence of vibration-damping Rubber Bearings. In vibration table tests, the ratio of similitude was set to 1/4. Linings and vibratingplatforms were fixed during scaled model tests to represent the integrated behavior ofthe ground and the applied models. In doing so, it was possible to minimize relativebehavior. The standard TBM cross-section for the virtual double-deck tunnel wasselected as a test subject. The level of ground motion exerted on the bedrock was setto 0.154 g (artificial seismic wave, Collapse Prevention Level and Seismic Category 1). A seismic wave with the maximum acceleration of 0.154 g was applied to the vibrationtable input (bedrock) to analyze resultant amplification in the models. As a result, theseismic stability of the middle slab was evaluated and analyzed with respect to thepresence of vibration-damping rubber bearings. It was confirmed that the presence ofvibration-damping rubber bearings improved its earthquake acceleration dampingperformance by up to 40%.