埋地管道多点非一致激励地震反应与简化分析方法研究

Buried Pipeline is a typical long-line underground structure, of which the seismic response is typically affected by the sites conditions and the spatial effects of earthquake motion. Many existing studies focused on the analysis of seismic response of buried pipeline at uniform sites. Research on complex site conditions is limited to theoretical and numerical analyses. It is difficult to fully reflect and reveal the nature characteristics of the seismic response of buried pipeline, the numerical and theoretical analysis models are urgently needed to verify through the shaking table tests of buried pipeline at non-uniform sites..The shaking table test of buried pipeline in non-uniform sites will be carried out relies on the completed non-uniform excitation shaking test of buried pipeline, considering the dynamic characteristics of soil, dynamic response of pipe and nonlinear pipe-soil interaction. The three-dimensional numerical model of buried pipeline which can consider nonlinear characteristics of soil will be established, and the numerical results will be verified by comparing with shake test results, and then the nonlinear soil-spring mechanics model of pipe-soil interaction is proposed by investigating the seismic response rules and influence factor of buried pipeline under non-uniform sites conditions. Based on the centralized mass discretization method, a simplified model of buried pipeline with consideration of nonlinear soil-spring mechanics model will be established, The rationality of the pipeline simplified analysis method is verified by comparing the results of shaking table test and numerical simulations..The research outcomes of this project provide theoretical reference for the seismic design and engineering construction of buried pipelines as well as improve the existing research on the soil-pipe interaction.

埋地管道属于典型的长线型地下结构，场地条件变化及地震动空间效应对其地震响应的影响是关键性的。已有研究多集中于均匀场地埋地管道的地震响应分析，对非均匀场地的研究仅限于理论及数值分析，很难全面反映和揭示管道地震反应的本质，亟需开展非均匀场地下的振动台试验，验证数值及理论模型的合理性。.依托申请人前期开展的埋地管道多点非一致激励振动台试验，补充开展非均匀场地埋地管道振动台试验。从研究土体动力参数、管道动力响应及管-土相互作用着手，搭建考虑土体非线性特性的埋地管道三维数值模型，并与试验结果进行比较，进而研究不同场地条件下埋地管道的地震响应规律及其影响因素，提出管-土相互作用非线性土弹簧力学模型。基于集中质量离散化方法建立考虑非线性土弹簧的管-土相互作用简化分析模型，并与试验和数值结果进行对比验证其合理性。.本项目研究成果在完善管-土相互作用研究的同时，可为埋地管道抗震设计理论及工程建设提供参考。

埋地管道是我国供油、供气、供水等领域重要的组成部分，其抗震安全性能对于维系城市和区域经济发展以及国家安全有至关重要的作用。地震观测资料和理论分析表明，作为典型的长线型地下结构，非一致地震激励对埋地管道地震响应的影响不容忽视。且相比于均匀场地，埋设在非均匀场地中管道的破坏率明显更高。鉴于此，本项目在已开展的非一致激励下埋地管道地震响应的振动台试验基础上，分析了在多点非一致激励下均匀、非均匀场中自由场和非自由场的地震响应，进一步通过大型有限元软件ABAQUS建立了一系列的三维有限元模型，并与振动台试验试验结果相互验证，证明了振动台试验以及数值模型的可靠性。同时建立埋地管道的集中质量简化模型，利用该模型研究长输埋地管道的地震反应特性，求得管道各集中质量点在纵向地震动作用下的动力响应。研究结果表明：在自由场试验中，非一致激励下土体的加速度放大系数与一致激励相比有所降低，这是由于非一致激励下土体运动不一致，导致了土体结构性的变化，土体刚度弱化，放大效应减弱，随着高度的增加拉压作用减弱，放大系数又逐渐增大；在非自由场试验中，非一致激励和非均匀场地对管道地震反应影响较大。与一致激励作用相比，非一致激励下的管道峰值应变增大两倍左右，与均匀场地相比，在一致、非一致激励作用下非均匀场地中管道的最大峰值应变增大约 10%～30%；.通过建立三维数值模型并与试验数据进行对比，数值模拟计算与振动台试验实测结果在加速度时程、加速度放大系数及沿管道轴向的应变峰值曲线等方面吻合较好，体现出了相似的规律，相互印证了数值模型和振动台试验结果的正确性。最后建立埋地管道的集中质量简化模型，并于规范推荐的弹性地基抗力系数的管道应变结果进行对比。依托项目发表学术论文9篇，其中SCI论文2篇，EI论文7篇。