Study on foamed concrete used as seismic isolation material for tunnels in rock

An orthogonal experiment was developed to study the effects of mix proportions on the properties of foamed concrete. Then, based on the demands of foamed concrete used as a seismic isolation material for tunnels in rock, the optimum mix proportions were obtained, and a new type of foamed concrete was developed. Test results showed that the new type of foamed concrete had low dry density, low water absorption rate, certain strength and good ductility. In addition, simulation results showed that the new type of foamed concrete used as coating material for tunnels in rock could significantly decrease the stress and plastic zone of the tunnel lining. In view of its good seismic isolation properties and the low cost of foamed concrete, it is suitable and feasible to use the new type of foamed concrete as seismic isolation material for tunnels in rock.