Influencing factors for seismic responds of a subsea tunnel
-
摘要:
本文基于Biot动力固结理论和弹性动力学理论,考虑海床(土壤)的两相性、黏弹性人工边界及流(水)-固耦合作用,建立了隧道-土-流体相互作用的力学模型,讨论了P波作用下有无水的情况以及水深、水域隧道埋深、海床土性质和地震波入射角等因素对隧道及其周围海床应力的影响。结果表明:隧道周围海床土的孔隙水压力和隧道内应力随着水深的增加而增加;地震波特性和海床土特性对隧道的内应力和海床土的孔隙水压力均有较大的影响;海床土的渗透性和隧道埋深对隧道的内应力影响较小,而对隧道周围海床土的孔隙水压力影响较大;地震动的入射角对隧道的内应力和隧道附近土层的孔隙水压力均有较大影响。
Abstract:Under the action of an earthquake, a sea tunnel is subjected to hydrodynamic pressure, so it is of great significance to study the dynamic response of sea tunnel under the combined action of earthquake and hydrodynamic pressure. Based on Biot’s theory of dynamic consolidation and elastodynamics theory, this paper established a mechanical model of tunnel-soil-fluid interaction by considering the two-phase property of seabed (soil) and the viscoelastic artificial boundary and the action of fluid (water)-structure interaction, and then discussed how the tunnel and its surrounding seabed are affected by the condition with or without water, and the depth of water, the buried depth of the tunnel, the nature of the seabed soil and change of incident angle. The results show that: ① the pore water pressure of the seabed soil and the internal stress of the tunnel increase with water depth increasing; ② different seismic wave and seabed soil characteristics have a great impact on the internal stress of the tunnel and the pore water pressure; ③ the permeability of seabed soil and the depth of the tunnel have a small effect on the internal stress of the tunnel, whereas it has a great effect on the pore water pressure of the seabed soil; ④ the incident angle of the seismic wave has a great influence on the internal stress of the tunnel and the pore water pressure of the seabed soil.
-
-
表 1 模型计算参数
Table 1 Model calculation parameters
饱和土体 泊松比 孔隙率 渗透系数/(m·s−1) 饱和度 密度/(kg·m−3) 弹性模量/MPa 0.33 0.35 10−2—10−4 1 1 900 50,200,400 混凝土隧道 隧道半径/m 隧道埋深/m 泊松比 密度/(kg·m−3) 弹性模量/MPa 6 2,4,8 0.2 2 400 30 000 表 2 不同工况下的计算参数
Table 2 Calculation parameters for six conditions
工况 地震动特性 入射角
/°土的模量
/MPa剪切波速
/(m·s−1)渗透系数
/(m·s−1)隧道埋深
/m水深
/m1 El-Centro波 0 200 − 10−3 4 0,20,40,80 2 El-Centro波,Kobe波 0 200 − 10−3 4 40 3 El-Centro波 0 − 100,200,400 10−3 4 40 4 El-Centro波 0 200 − 10−2,10−3,10−4 4 40 5 El-Centro波 0 200 − 10−3 2,4,8 40 6 El-Centro波 0,15,30,45,60 200 − 10−3 4 40 表 3 不同测点在不同入射角作用下位移放大系数
Table 3 Displacement magnication factor of different measuring points with different incident angles
测点入射角/° 位移放大系数 测点1 测点2 测点3 测点4 测点5 测点6 0 1.46 1.47 1.48 1.46 1.46 1.44 15 1.35 1.37 1.40 1.41 1.41 1.36 30 1.39 1.42 1.46 1.47 1.39 1.39 45 1.40 1.42 1.48 1.48 1.40 1.39 60 1.32 1.34 1.38 1.38 1.38 1.31 -
陈贵红. 2005. 沉管隧道地震响应的影响因素分析[J]. 中国铁道科学,26(6):93–97. doi: 10.3321/j.issn:1001-4632.2005.06.019 Chen G H. 2005. Analysis of the affecting factors for seismic response of immersed tunnel[J]. China Railway Science,26(6):93–97 (in Chinese).
陈向红,张鸿儒. 2012. 暗挖海底隧道地震动水压力响应分析[J]. 北京交通大学学报,36(1):36–40. doi: 10.3969/j.issn.1673-0291.2012.01.007 Chen X H,Zhang H R. 2012. Analysis of effect of hydrodynamic pressure on undersea tunnels constructed by excavation method[J]. Journal of Beijing Jiaotong University,36(1):36–40 (in Chinese).
崔杰,欧阳志勇,朱飞,曾凡凯. 2015. 波浪荷载作用下海底隧道-孔隙海床的动力分析[J]. 震灾防御技术,11(3):513–527. Cui J,Ouyang Z Y,Zhu F,Zeng F K. 2015. Dynamic analysis of the channel tunnel-porous seabed under wave load[J]. Technology for Earthquake Disaster Prevention,11(3):513–527 (in Chinese).
董新平. 1999. 南京长江沉管隧道竖向地震反应分析[J]. 隧道建设,19(3):26–31. Dong X P. 1999. Dynamic response analysis of Nanjing Yangtze River immersed tunnel subjected to vertical earthquake motion[J]. Tunnel Construction,19(3):26–31 (in Chinese).
刘晶波,王振宇,杜修力,杜义欣. 2005. 波动问题中的三维时域粘弹性人工边界[J]. 工程力学,22(6):46–51. doi: 10.3969/j.issn.1000-4750.2005.06.008 Liu J B,Wang Z Y,Du X L,Du Y X. 2005. Three-dimensional visco-elastic artificial boundaries in time domain for wave motion problems[J]. Engineering Mechanics,22(6):46–51 (in Chinese).
杨辉,陆建飞, 王建华,张庆华. 2001. 黄浦江过江隧道的动力抗震分析[J]. 上海交通大学学报,35(10):1512–1515. Yang H,Lu J F,Wang J H,Zhang Q H. 2001. Vibration analysis of a subaqueous tunnel of Huangpu River during earthquake[J]. Journal of Shanghai Jiaotong University,35(10):1512–1515 (in Chinese).
赵密. 2009. 近场波动有限元模拟的应力型时域人工边界条件及其应用[D]. 北京: 北京工业大学: 1−127. Zhao M. 2009. Stress-Type Time-Domain Artificial Boundary Condition for Finite-Element Simulation of Near-Field Wave Motion and Its Engineering Application[D]. Beijing: Beijing University of Technology: 1−127 (in Chinese).
中华人民共和国住房和城乡建设部, 中华人民共和国国家质量监督检验检疫总局. 2010. GB50011—2010 建筑抗震设计规范[S]. 北京: 中国建筑工业出版社: 6−7. Ministry of Housing and Urban-Rural Development of the People’s Republic of China, General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China. 2010. GB50011−2010 Code for Seismic Design of Building[S]. Beijing: China Architecture & Building Industry Press: 6−7 (in Chinese).
Anastasopoulos I,Gerolymos N,Drosos V,Kourkoulis R,Georgarakos T,Gazetas G. 2007. Nonlinear response of deep immersed tunnel to strong seismic shaking[J]. J Geotech Geoenviron Eng,133(9):1067–1090.
Biot M A. 1941. General theory of three-dimensional consolidation[J]. J Appl Phys,12(2):155–164. doi: 10.1063/1.1712886
Taylor P R,Ibrahim H H,Yang D. 2005. Seismic retrofit of George Massey tunnel[J]. Earthq Eng Struct Dyn,34(4/5):519–542.