Experimental study on yielding and relief pressure support technology of fluid-filled lining in a high-ground stress soft rock tunnel

Abstract

High-ground stress soft rock tunnels have experienced large deformations. Yielding and pressure relief fluid-filled lining support technology is an effective method for solving large soft rock tunnel deformation due to the deformation characteristics of high-ground stress soft rock tunnels. To give the surrounding rock a certain amount of deformation space, a layer of fluid filling is set up at the reserved deformation of the tunnel. By creating a force test model of the inflatable carcass and water-filled carcass, the straight section of the tunnel support structure is simulated. When supporting large deformation soft rock tunnels, inflatable and water-filled carcasses produce fluid homogenization load shedding and fluid drainage load shedding effects. Inflatable carcasses and water-filled carcasses without leakage reduce load by about 28% and 7%, respectively. The peak load reduction rate under liquid leakage can gradually reach 100 %. Inflatable carcasses can dissipate up to 90% of the work of external forces acting on the supporting structure. The load reduction rate of water-filled carcass is 1.2 times that of inflatable carcass. Fluid-filled materials can remove load from secondary lining support structures after yielding and pressure relief. Design and construction of high-ground stress soft rock tunnels can be influenced by research results.