强震区泡沫混凝土隧道减震层动力特性与减震机理研究

The active seismic faults are well developed in the southwest of China, and earthquakes seriously threaten the safety of tunnels in this area. So the aseismic design method for tunnels has become a urgent problem to be solved. In view of this problem, the seismic isolation layer of the tunnel based on foamed concrete is proposed. First, the rate-dependent and fatigue damage characteristics for foamed concrete will be studied through monotonic mechanical tests under different strain rates and cyclic loading tests. And a constitutive model for foamed concrete will be established. Second, the cyclic shear tests on the contact surfaces between the surrounding rock and the buffer layer will be carried out, aiming at studying the effect of normal stress, shear rate, roughness and cyclic number on the mechanical characteristics for the contact surfaces. And the shear strength and fatigue wear function for the contact surfaces will be proposed in order to reveal the transfer law of seismic load at the interface. Third, the aforementioned mechanical models will be implemented by programming in finite element software ABAQUS. Finally, combined the supporting engineering project, the mechanism of the buffer layer will be revealed in adverse conditions through parametric studies, and the corresponding control measures will be proposed. From this study, a scientific guide will be provided for the design and construction of the seismic isolation layer for tunnels in high intensity zone.

我国西南地区地震断裂带发育，地震活动频发，震害严重威胁着该地区隧道的安全稳定，建立高效的抗震、减震措施及分析理论已成为隧道建设过程中亟待解决的难题。为此，本项目拟以泡沫混凝土作为隧道减震材料，开展泡沫混凝土在不同应变速率下的压缩试验与不同频率、幅值周期荷载作用下的三轴循环加卸载力学试验，研究材料的应变率效应与疲劳效应，并建立材料的动力本构模型；开展围岩（衬砌）-减震层界面的循环剪切试验，研究法向应力、剪切速率、粗糙度、循环次数对界面力学性能的影响，建立接触面抗剪强度公式与摩擦角的磨损演化函数，揭示地震荷载在界面处的传递规律。基于有限元软件ABAQUS，通过二次开发实现减震层力学模型的数值仿真。结合依托工程，通过系统的参数分析揭示强震区不良地质条件下隧道减震层减震性能的变化规律，并基于场地条件与隧道结构特征提出减震控制措施。研究成果将为强震区隧道减震层的设计与施工提供理论依据与技术支持。

我国西南地区地震断裂带发育，地震活动频发，震害严重威胁着该地区隧道的安全稳定，建立高效的抗震、减震措施及分析理论已成为隧道建设过程中亟待解决的难题。本项目以泡沫混凝土作为隧道减震材料，开展了不同干密度泡沫混凝土试样在不同围压、不同应变速率条件下的压缩试验与三轴循环加卸载试验，研究了材料的应变率效应与疲劳效应，并建立了材料的动力本构模型。接着，开展了砂岩-泡沫混凝土胶接界面的剪切试验，研究了界面的破坏形态及损伤演化规律，并基于Mohr-Coulomb破坏准则建立了界面的接触力学模型。结合有限元分析软件ABAQUS，建立了泡沫混凝土材料及围岩-减震层界面力学模型的数值仿真技术。最后，依托西藏嘎隆拉隧道及云南香炉山隧洞，采用数值及理论分析方法揭示了洞口段、跨断层区隧道减震层减震机理以及加固圈与减震层的协同工作机制。相关成果为研究地震波在隧道复合式衬砌中的传播规律提供了新方法，为高烈度区复杂地质条件下隧道减震层的设计提供了理论依据与技术支持。项目资助发表学术论文6篇，授权专利6项，培养博士生2名。