【摘要】 考虑地震荷载特征及隧道特点,运用多点同时激振的动力时程分析方法,采用结构面单元与实体单元组合模拟断层带的方法,研究了某穿越断层破碎带铁路隧道在未支护条件下的动力响应特性。分析了沿隧道横向、纵向和竖向激振地震动工况下与断层破碎带接触部位所产生的位移差、加速度放大倍率和屈服单元等。结果表明:结构面单元与实体单元组合合理模拟了断层破碎带的地震响应特性;地震运动引起断层破碎带接触部位产生明显的位移差,横向输入地震动时位移差值最大,达到51.8mm,而沿纵向和竖向输入时,位移差值仅为横向输入的44.3%和23.1%;同一高程处断裂带的加速度放大倍率明显大于混合花岗岩;断裂带与混合花岗岩过渡段出现明显的剪切屈服区域,且横向、竖向输入地震动时尤其突出;断层破碎带对隧道在地震动作用下的响应规律影响显著,穿越断裂带隧道的断裂带部位与过渡段为抗震设计控制性区域,应深入加强抗震措施研究。更多还原

【Abstract】 Based on dynamic time history analysis,dynamic response behavior of an un-supported tunnel through fault zone which was simulated by interface and solid elements was studied under uniform input earthquake wave excitation.The analyses of response behaviors,including displacement difference,acceleration magnification,and plastic zones and so on,were carried out when earthquake wave excitation was input along transverse,longitudinal and vertical of tunnel respectively.The results show that simulation method for fault zone is effective;the earthquake causes obvious displacement difference at fault zone and surrounding rock contacting part.The maximal displacement difference reaches to 51.8mm under transverse uniform input earthquake wave excitation.And the displacement difference under vertical and longitudinal is only 44.3% and 23.1% of the transverse value,respectively;the acceleration magnification in fault zone is significantly greater than that in surrounding rock.Shear failure zone appears at the fault zone and surrounding rock contacting part,and it is especially prominent under input longitudinal earthquake wave excitation.It is proposed that fault zone has significantly influence on the dynamic performance of tunnel.The fault zone and the transitional zones are the control zones of seismic design when tunnel passes through fault zone,thus,the study on the anti-seismic measures should be further strengthened.更多还原