精选文档 γ(kN/m3)

25 16.7 17.0 reasonable E(MPa)

29.5 0.66 0.72 reasonable σc (MPa) 12.5 0.3 0.426 approximately 4 Test measurement and scheme

4.1 Strain measurement of tunnel structure

Strain gauges are firstly arranged for the tunnel site where the internal force and deformation of tunnel is maximal. The sensor wire should be firmly fixed at the surface of the model structure and fetched out from the certain position where the model displacement is lesser at that direction. The schematic diagram of measurement points are laid in Figure.1 in order to verify the dynamic response law of tunnel structure.

Figure.1 Layout scheme of sensors Figure.2 Accelerations time-histories curve

4.2 Test load ---earthquake wave

The earthquake waves adopted is the artificial wave that is synthesized by the Sichuan Seismological Bureau under the conditions of the site response spectrum synthesis in model test. The exceedance probability of earthquake waves is2% , the original peak acceleration is 0.67g, the hold time is about 20s in the part of strong shock, most of the earthquake waves Energy is less than 15s and is within 15Hz in the frequency (in Figure. 2).