地震荷载作用下锦屏地下厂房动力分析
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摘要
锦屏地下厂房洞室群规模巨大,厂区断层及裂隙密集带发育,实测最大主应力达35.7 MPa,为高地应力区。该区基本烈度VII度,50年超越概率5%的水平峰值加速度达到0.167 g,抗震问题突出。采用输入加速度时程法,对该地下厂房5#机组段二维有限元模型进行动力时程分析。结果表明:5#机组段进行系统支护后,在地震荷载作用下,三大洞室协调振动,上下游边墙处动位移及速度差异较小;厂区水平向及铅直向加速度约为2.7 m/s2和1.9 m/s2,分别为输入加速度的1.65和1.73倍;围岩动力破坏区及动拉应力区分布规律与静力作用下相近,但其深度和量值有所增加,且在局部区域有新拉应力区生成;动拉应力区深度在3.7 m以内,其量值一般小于0.2 MPa,说明加固措施有效,可以满足抗震要求。
The underground powerhouse of Jinping hydro-power station is composed of large cavern system. The surrounding rock consists of fault and fissure zone,with measured maximum geo-stress up to 35. 7MPa,so the power house locates in high stress area. The basic seismic intensity of the dam site area is VII,the crest value of earthquake acceleration that 50 years beyond the probability of 5% is 0. 167 g. In this paper,dynamic analysis was carried out on 2D finite element model of 5# unit section by inputting acceleration time-history wave. The result shows that under seismic action,three large caverns of 5# unit section were coordination vibrated after system support,and the acceleration of horizontal directional acceleration was 2. 7 m / s2,while 1. 9 m/s2in the Vertical direction,or in another word 1. 65 and 1. 73 times the input acceleration. The distribution regularity of dynamic failure zone and dynamic tensile stress zone of surrounding rock were close to which under static load,but the depth and value were increased,and the reinforcement measures can meet the seismic requirements.
The underground powerhouse of Jinping hydro-power station is composed of large cavern system. The surrounding rock consists of fault and fissure zone,with measured maximum geo-stress up to 35. 7MPa,so the power house locates in high stress area. The basic seismic intensity of the dam site area is VII,the crest value of earthquake acceleration that 50 years beyond the probability of 5% is 0. 167 g. In this paper,dynamic analysis was carried out on 2D finite element model of 5# unit section by inputting acceleration time-history wave. The result shows that under seismic action,three large caverns of 5# unit section were coordination vibrated after system support,and the acceleration of horizontal directional acceleration was 2. 7 m / s2,while 1. 9 m/s2in the Vertical direction,or in another word 1. 65 and 1. 73 times the input acceleration. The distribution regularity of dynamic failure zone and dynamic tensile stress zone of surrounding rock were close to which under static load,but the depth and value were increased,and the reinforcement measures can meet the seismic requirements.
引文
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[2]张雨霆,肖明,李玉婕.汶川地震对映秀湾水电站地下厂房的震害影响及动力响应分析[J].岩石力学与工程学报,2010,29(S2):3663-3670.
[3]郑永来,杨林德.地下结构震害与抗震对策[J].工程抗震,1999,(4):23-28.
[4]李海波,马行东,李俊如,等.地震荷载作用下岩体洞室位移特征的影响因素分析[J].岩土工程学报,2006,28(3):358-362.
[5]王如宾,徐卫亚,石崇,等.高地震烈度区岩体地下洞室动力响应分析[J].岩石力学与工程学报,2009,28(3):568-575.
[6]李海波,蒋会军,赵坚,等.动荷载作用下岩体工程安全的几个问题[J].岩石力学与工程学报,2003,22(11):1887-1891.
[7]隋斌,朱维申,李晓静.地震荷载作用下大型地下洞室群的动态响应模拟[J].岩土工程学报,2008,30(12):1877-1882.
[8]李良权,方丹,杨忠良.地下厂房洞室群动力反应时程分析[J].三峡大学学报:自然科学版,2012,34(3):1-5.
[9]张建海,何江达,范景伟,等.天龙湖地下厂房地震动力放大区及动拉力区三维有限元分析[J].四川大学学报:工程科学版,2002,34(4):10-13.
[10]黄润秋,王贤能,唐胜传.深埋隧道地震动力响应的复反应分析[J].工程地质学报,1997,5(1):1-7.
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