断层错动诱发上覆土体破坏对跨越断层的埋地管道结构安全构成巨大威胁,是复杂环境地下管线设计中不可忽略的场地因素。既有成果较少涉及正断层和逆断层错动影响下的解析解分析,且针对断层-管道相互作用的理论研究一般将管道结构视为连续管道,较少考虑管道接口的影响。首先,在简化SSR(静止区stationary zone,剪切区shearing zone,刚体区rigid body zone)土体变形模型的基础上,结合erf函数和erfc函数,得到了正断层和逆断层错动影响下的土体位移曲线;其次,引入双参数Pasternak地基模型,对管道微元进行受力分析,借助有限差分法求解得到埋地管道结构的变形和内力;最后,将理论解析解和已有的试验结果及数值模拟结果进行对比验证,获得了较好的一致性。此外,针对断层倾角、断层与管道交点位置和接口转动刚度等关键物理特征参数进行了敏感性分析。结果表明:断层倾角会改变管道位移曲线和轴向应力曲线位置,但其位移最大值和轴向应力最大值基本一致,而断层与管道交点位置不仅会改变管道位移曲线和轴向应力曲线形状,其轴向应力最大值也将发生改变;随着接口转动刚度增大,管道最大轴向应力值随之增大,当接口转动刚度足够大时,可将非连续管道视作连续管道进行计算。
Abstract
Damage to the overlying soil caused by fault misalignment poses a significant threat to the structural safety of buried pipelines crossing faults
which is a non-negligible factor in the design of underground pipelines in complex environments. Existing research rarely involves analytical solutions for the force and deformation of pipeline structures under normal and reverse fault movements
and theoretical studies on fault-pipeline interactions often treat the pipeline structure as continuous
with little consideration for the influence of pipeline joints. Firstly
soil displacement curves for both normal and reverse faults are derived using the erf and erfc functions
based on a simplified SSR (stationary zone
shearing zone
rigid body zone) soil deformation model. Secondly
the deformation and internal force of the buried pipeline structure are solved using the two-parameter Pasternak foundation model and the finite difference method. Finally
the theoretical analytical solution is compared with existing experimental and 3D numerical simulation results
showing good agreement. In addition
sensitivity analyses are conducted for key physical parameters
including fault dip
fault-pipeline intersection location
and joint rotation stiffness. The results show that fault dip will change the position of the pipeline displacement curve and axial stress curve
but the maximum displacement and maximum axial stress are basically identical. The intersection of the fault and the pipeline will not only change the shape of the pipeline displacement curve and axial stress curve
but also alter the maximum axial stress. With the increase of joint rotation stiffness
the maximum axial stress value of the pipeline increases. When the joint rotation stiffness is large enough
the jointed pipeline can be calculated as if it is continuous.