【摘要】 目的为深入研究山岭隧道二次衬砌在地震中的受力特征和破坏机制,解释衬砌结构环向裂缝的产生原因.方法基于应答变位法理论,以汶川地震中受到破坏的龙溪隧道作为研究对象,采用有限元方法研究了山岭隧道二次衬砌沿其轴线方向的地震响应规律.结果在隧道内离洞口1 000 m的区域,衬砌结构的轴向拉应变最大值达到了150×10-6,远高于C25级混凝土的极限拉应变,该区域首先发生环向断裂.结论隧道结构的地震响应受其所在岩体受震时发生的相对变位所支配.强烈的地震发生过程中,沿隧道轴线方向的衬砌结构可能承受强烈的拉压作用.当衬砌混凝土的实际应变超过其极限应变时,会发生衬砌结构的环向开裂和混凝土剥落.更多还原

【Abstract】 In order to study the stress characteristics and failure mechanics of secondary lining of a mountain tunnel in an earthquake,interpret the cause of ring cracks on tunnel′s lining structure,a finite element modeling analysis based on the response displacement method has been performed to simulate the earthquake response,taking the Longxi tunnel which has been destroyed in the Wenchuan earthquake as an study object.The calculation result shows that,the axial tensile strain on the lining structure reached as high as 150×10-6 at the area 1 000 m inside the tunnel.Because this strain is much higher than the ultimate tensile strain of the lining material,C25 concrete,ring crack occurs.The seismic response of tunnel structure subjects to the relative deformation of its surrounding rock mass during an earthquake.In a strong earthquake,the axial tunnel structure can be subjected to intensive axial loads.Ring crack and concrete spalling occurs on the lining structure when the actual strain in the lining concrete exceeds the materials′ultimate strain.更多还原