摘要
高水压及上覆淤泥层等复杂地质条件是影响海底隧道渗流特征与防排水设计的关键因素。为系统研究海底隧道周围水压分布规律及涌水量特征,基于水力学理论,推导考虑上覆淤泥层的海底隧道渗流场解析解,并建立相应的数值模型,通过与理论结果的对比分析,验证数值模型的适用性和准确性。通过数值模拟,获得海域段隧道最优限量排水方案与合理泄压值,进一步探究淤泥层厚度和覆盖率等因素对隧道涌水量及衬砌背后水压力分布特征的影响规律,揭示上覆淤泥层对海底隧道渗流特征的作用机理。结果表明:(1)随着泄压值的增大,隧道排水量呈线性递减趋势,衬砌背后水压力呈线性增大;在相同泄压值条件下,随着环向排水盲管间距的增大,隧道排水量逐渐减小,衬砌背后水压力逐渐增大。(2)在淤泥厚度为12 m时海域矿山法段隧道最优限量排放方案为半包防水型式,排水方式选取“间隔6 m环向排水盲管+纵向排水盲管”,泄压值为400 kPa。(3)淤泥层厚度和覆盖率的增加可以减小排水量并在一定程度上降低衬砌背后水压力;在弱风化花岗岩与淤泥覆盖层交界处,衬砌背后水压力出现一定程度的突变,应重点考虑通过确定的淤泥层覆盖率或局部淤泥层厚度来合理优化排水系统的排水参数。
The complex geological conditions such as high water pressure and overlying silt layer are the key factors that affect the seepage characteristics and the waterproofing and drainage design of subsea tunnels.In order to sys⁃tematically investigate the ambient water pressure distribution pattern and water inflow characteristics of subsea tun⁃nel,the analytical solution for seepage field of subsea tunnel that takes into account overlying silt layer has been de⁃duced by using the hydromechanical theories,and the corresponding numerical model has been created.Through comparison and analysis of the theoretical results,the suitability and accuracy of the numerical model have been verified.Through numerical simulation,the optimum limited drainage scheme and rational depressurization value for subsea tunnel have been obtained,the laws by which the factors such as silt layer thickness and coverage rate will affect the tunnel water inflow and the water pressure distribution pattern behind the lining have been further in⁃vestigated,and the mechanism of action of overlying silt layer on the seepage characteristics of subsea tunnel have been revealed.As the results indicate:(1)As the depressurization value increases,the water drainage of tunnel de⁃creases linearly,while the water pressure behind the lining increases linearly.With the same depressurization value,as the spacing between the circumferential French drain pipes increases,the water drainage of tunnel gradually de⁃creases,while the water pressure behind the lining gradually increases.(2)When the silt layer thickness is 12 m,the optimum limited drainage scheme for mined subsea tunnel is as follows:for semi-closed waterproofing method,the waterproofing system is"circumferential French drain pipe+longitudinal circumferential French drain pipe with 6 m spacing",and the depressurization value is 400 kPa.(3)Increase of the silt layer thickness and coverage rate will decrease the water drainage and,to certain extent,decrease the water pressure behind the lining.At the junction between weakly weathered granite and silt overburden,the water pressure behind the lining changes abruptly,so priority should be given to optimizing the water drainage parameters of the drainage system according to the known silt layer coverage rate or local silt layer thickness.
作者
靖一峰
汪波
梅洁
熊文威
孟庆余
JING Yifeng;WANG Bo;MEI Jie;XIONG Wenwei;MENG Qingyu(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031;Institute of Urban Rail Transportation,Southwest Jiaotong University,Chengdu 611756;China Railway Design Corporation,Tianjin 300308)
出处
《现代隧道技术》
CSCD
北大核心
2024年第1期84-95,共12页
Modern Tunnelling Technology
基金
国家自然科学基金(U2034205)
中央高校基本科研业务费专项资金(2682022CX073)
浙江省交通科技项目(2021051)
四川交通科技项目(2021-MS1-030,2021-B-01)
国铁集团系统性重大项目(P2022G055)
中国铁路设计集团有限公司科技开发课题(2020YY240610)
中国国家铁路集团有限公司科技研究开发计划项目重大课题(K2020G033).
关键词
海底隧道
淤泥覆盖层
排水量
水压力分布
限量排放
Subsea tunnel
Silt overburden
Water drainage
Water pressure distribution
Limited drainage
