减震层对跨断层隧道抗错断效果的模型试验研究

Model Experimental Study on Anti-dislocation Effect of Shock Absorption Layer on Cross-fault tunnel

为了研究跨断层隧道设置减震层时的抗错断效果以及跨断层隧道衬砌的破坏特征,以敦(敦煌)格(格尔木)铁路阔克萨隧道为依托,采用室内模型试验的方法,研究减震层对跨断层隧道在断层错动时的受力特征以及对跨断层隧道的减错效果,结果表明:不论是否设置减震层,跨越断层隧道节段以及与之相连的节段在断层错动时的受力较大、破坏较严重,是跨断层隧道抗错断的重点设防部位;设置减震层后衬砌应变和接触压力均有所减小,但减震层对接触压力的减小幅度要大于对应变的减小幅度;设置减震层后,断层错动引起衬砌环向应变的增大倍数在4.8~14.2,最大降低11.7%,接触压力增大倍数在1.4~5.6,最大降低11.9%,跨断层节段以及与之相连节段衬砌的破坏情况明显减弱,对跨断层隧道衬砌防错断具有较好的效果。

In order to understand the anti-dislocation effect and the damage characteristics of the lining of cross-fault tunnels with shock absorption layer, stress characteristics and anti-dislocation effect of the shock absorption layer on cross-fault tunnel are studied by means of model experimental method based on the Kuokesa Tunnel on Dunhuang-Golmud Railway. The results show that: whether or not shock absorption layer is installed, the section of tunnel across fault and the section connected with it are suffer greater stress and serious damage when the fault dislocates. These sections are the key locations for anti-dislocation of the tunnel across fault. The strain and contact pressure of lining tend to decrease after setting shock absorption layer, but the reduction of contact pressure of the shock absorption layer is larger than that of strain. After setting shock absorption layer, circumferential strain caused by fault dislocation is increased by 4.8 to 14.2 times, and the maximum decrease is 11.7%. While, the contact pressure is increased by 1.4 and 5.6 times, and the maximum decrease is 11.9%. The damage of the lining of the section across fault and its adjacent section decreases obviously, which has a good effect on preventing tunnel lining from dislocation.