【摘要】 结合南京某具体工程,该盾构隧道具有大断面、所处场地地质条件差等特点,将盾构隧道简化为与其纵向变形一致的等价梁,建立等价连续化模型,采用反应位移法进行盾构隧道纵向弹塑性地震反应分析。计算中考虑轴向力和弯矩同时作用,考虑螺栓预紧力的影响。考虑输入地震动水准的影响,考虑输入角度的问题,计算以下几种工况:输入地面速度峰值PGV=0.15m/s(相当于设防烈度7度)和地面速度峰值PGV=0.30m/s(相当于设防烈度8度);入射角度分别为0°、30°、45°、60°。最后将反应位移法计算结果与三维有限元动力时程分析结果进行比较。计算结果表明:接头张开量是盾构隧道纵向抗震的重要指标,建议采用此指标作为抗震设防控制指标;输入角度和输入地震动水准是纵向抗震分析的重要影响因素,应选取最不利荷载情况作为控制工况;反应位移法计算简单,只要参数选取合理,可以得到适合工程应用的结果。更多还原

【Abstract】 Response deformation method is applied to analysis the longitudinal seismic response of the shield tunnel for the specific project across Yangtze River in Nanjing.The shield tunnel is simplified to a line beam to establish equivalent continuous model,which has the same longitudinal deformation with the shield tunnel.The axial force and bending moment are simultaneously considered in calculating and the pre-stress of bolts is also considered.According to the impact of the inputting angle and the level of strong motion,inputting is divided into the following cases: inputting by PGV = 0.15m / s(equivalent to 7 degrees seismic fortification intensity) and PGV = 0.30m / s(equivalent to 8 degrees seismic fortification intensity),incident angles are respectively 0°,30°,45°,60°.Then,the results by response deformation method are compared with that by the 3-D finite element method,and the similar results can be obtained.The results indicate that:(1) Response deformation method is a simple and practical tool for engineering application,e.g.for longitudinal seismic response analysis of large sectional shield tunnel;(2) Amount of joint opening is directly obtained by response deformation method,as an important parameter for the anti-seismic design of shield tunnel,which is recommended as a dynamic indicator for evaluation and control of structure response during large earthquake occurring;(3) Incident angle and level of inputting strong motion(acceleration,velocity and displacement) have an important effect on longitudinal seismic analysis,the most unfavorable load case should be selected as a control condition for design and study of engineering.更多还原