摘要
海底沉积物中气体通常以不连续的气相存在于海床土体中,既有理论研究较少考虑含气海床环境,波浪动压力引起的渗透力导致隧道衬砌附加变形也较少见之于文献。首先,通过Biot固结方程获得了气-水混合流控制方程,结合适用于浅水区的Stokes二阶非线性波浪理论获得了隧道衬砌周围的孔隙水压响应;其次,采用叠加法分别考虑了由波浪引起的海床土体内振荡孔压和累积孔压,并以衬砌周围可能出现的最大孔隙水压及渗透力作为最不利荷载工况,结合指数衰减模型描述衬砌劣化效应,获得了考虑波浪渗透力作用下隧道衬砌服役期间位移变化规律;最后,通过试验监测数据及数值模拟验证了本研究理论解析的准确性,通过对波浪周期、水深,海床剪切模量、海床含气量,隧道半径、埋深、衬砌劣化系数进行分析。结果表明:海床含气量增大能降低波浪压力向海床内部传播,并减弱超静孔压的累积效应;随着海床含气量逐渐增大,隧道衬砌周围孔压极值不断减小且出现相位滞后,隧道外渗透力、衬砌径向位移均随着海床含气量增加而明显降低;波浪周期增大、海水深度降低均能明显使海床表面的波浪压力增大,诱发隧道衬砌周围产生较大的渗透力,从而发生较大径向位移,小半径、浅埋深能够有效降低累积孔压造成的渗透力影响;当衬砌劣化系数相同时,含气量越低的海床内波浪引起的超静孔隙水压影响越显著,衬砌产生较大径向位移,不利于隧道的正常服役。
The gas in the seabed sediment exists in the seabed soil as discontinuous gas phase,existing theoretical studies seldom consider the gassy seabed environment,and there are few studies on the additional deformation of the tunnel lining caused by the seepage force induced by the wave dynamic pressure.Firstly,the control equation of gas-water mixed flow is obtained by Biot consolidation equation,and the pore water pressure response around the tunnel lining is obtained by combining with Stokes second-order nonlinear wave theory suitable for shallow water.Secondly,the superposition method is used to consider the oscillatory pore pressure and cumulative pore pressure in the seabed soil caused by waves,and the maximum pore water pressure and seepage force that may appear around the lining are taken as the most unfavorable load cases.The displacement variation law of the tunnel lining during service under the action of wave seepage force is obtained in combination with the exponential decay model to describe the lining deterioration effect.Finally,accuracy of the theoretical analysis in this paper is verified by the experimental monitoring data and numerical simulation.Parameter analyses are made on the wave period,water depth,seabed shear modulus,seabed gas content,tunnel radius,burial depth and lining deterioration.The cumulative effect of wave pressure propagating into the seabed and excess pore water pressure can be weakened when the seabed gas content increases.The extreme pore pressure around the tunnel lining decreases and the phase lag occurs with the increase of the gas content in the seabed.The external seepage force and the radial displacement of the lining decrease significantly with increasing the gas content in the seabed.Larger wave period and shallower seawater depth can significantly increase the wave pressure on the seabed surface,and induce greater seepage force around the tunnel lining,resulting in greater radial displacement.Reducing the radius and depth of the tunnel can effectively weaken the influence of the seepage force caused by the accumulated pore water pressure.When the lining deterioration coefficient is constant,the influence of excess pore water pressure caused by waves in the seabed with lower gas content is more significant,and the lining produces large radial displacement,which is not conducive to the normal service of the tunnel.
作者
张治国
叶铜
朱正国
PAN Y T
吴钟腾
ZHANG Zhi-guo;YE Tong;ZHU Zheng-guo;PAN Y T;WU Zhong-teng(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang,Hebei 050043,China;Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation,North Sea Marine Forecast Center of State Oceanic Administration,Qingdao,Shandong 266061,China;Key Laboratory of Geohazard Prevention of Hilly Mountains,Ministry of Natural Resources,Fujian Key Laboratory of Geohazard Prevention,Fuzhou,Fujian 350002,China;Department of Civil and Environmental Engineering,National University of Singapore,Singapore 119077)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第6期1557-1574,共18页
Rock and Soil Mechanics
基金
国家自然科学基金(No.41977247,No.42177145)
省部共建交通工程结构力学行为与系统安全国家重点实验室课题(No.KF2022-07)
自然资源部丘陵山地地质灾害防治重点实验室课题(No.FJKLGH2020K004)
山东省海洋生态环境与防灾减灾重点实验室课题(No.201703)。
关键词
海底盾构隧道
含气海床
累积孔压
渗透力
衬砌劣化
subsea shield tunnel
gassy seabed
cumulative pore pressure
seepage force
lining deterioration
