实验技术与管理

该文以雅安大石板隧道为依托工程，研究了浅埋隧道穿越边坡体系在地震作用下的动力响应特征。研究首先在三向六自由度振动台平台完成了模型箱布置、地质结构还原、衬砌制作及传感器布设等准备工作；然后构建了1∶50缩尺边坡-双隧道模型，采用汶川波作为地震输入，设定0.1 g、0.3 g、0.6 g三级加速度工况，模拟实际地震作用；最后分析了边坡破坏特征、高程放大效应及隧道衬砌的动态响应特征。实验结果表明：坡体破坏形式多样，具有明显空间分异性；坡顶加速度响应增强，存在高程放大效应；埋深较深段隧道衬砌损伤更重，主要集中于拱顶、仰拱和拱脚；结构应变随地震强度呈非线性增长，左右洞响应不同。实验结果为边坡-双隧道体系抗震设计提供了依据。

[Objective] The dynamic behavior and seismic response of shallow-buried twin tunnels crossing slopes are critical issues in tunnel engineering, particularly in earthquake-prone regions. Given the frequent occurrence of earthquakes and landslides in Sichuan Province, research on seismic-induced dynamic interactions between slopes and tunnels is urgent and of practical significance. This study aims to investigate the dynamic response characteristics and damage mechanisms of slope-tunnel systems subjected to seismic loading, providing experimental data and theoretical insights crucial for the seismic design and construction safety of these types of infrastructures. The study focuses on the Dashi Ban tunnel in Ya'an, providing realistic insights into seismic mitigation measures and disaster prevention strategies. [Methods] To achieve a thorough understanding of the interactions between slopes and tunnels under seismic loads, a large-scale shaking table test was conducted at Southwest Jiaotong University's three-dimensional, six-degree-of-freedom shaking table facility. This involved meticulously preparing a scaled physical model(1:50) that accurately replicates the geological structure, slope configuration, and twin-tunnel geometry based on the Dashi Ban tunnel project. The slope-tunnel system model featured carefully designed lining structures, detailed sensor arrangements, and precise soil compaction to achieve an accurate simulation of the original engineering conditions. The input seismic wave was modeled using the historical Wenchuan earthquake record, reflecting realistic seismic excitation typical for the region. Three different seismic intensity levels(0.1 g, 0.3 g, and 0.6 g) were applied to analyze the dynamic responses and damage evolution systematically. Various sensors, including accelerometers, strain gauges, displacement transducers, and high-speed cameras, were strategically placed to monitor slope displacement, acceleration response, lining strains, and overall structural performance during seismic excitations. [Results] The experimental results provided detailed insights into slope failure modes, acceleration response amplification, and the unique structural responses of the twin tunnels under varying seismic intensities. The slope exhibited clear spatial heterogeneity in damage patterns, with the upper regions experiencing significantly higher accelerations and more severe deformations than the lower sections. A notable amplification effect was observed, indicating that seismic response intensity increased with slope height. Analysis of tunnel lining responses revealed distinct deformation characteristics heavily influenced by the tunnel's burial depth. Deeper segments exhibited greater vulnerability, showing substantial cracking and structural degradation primarily at the crown, invert, and sidewall footings. In addition, the structural strain within the tunnel linings demonstrated a pronounced non-linear relationship with increasing seismic intensity, highlighting critical transition thresholds at particular accelerations. The left and right tunnels displayed different response characteristics owing to their spatial relationships and interaction dynamics, underscoring the need for individualized assessments within twin-tunnel systems. [Conclusions] The shaking table test systematically elucidated the seismic-induced dynamic responses and failure characteristics of slope-tunnel systems, highlighting critical factors, including burial depth effects, seismic intensity, and spatial amplification effects. The observed non-linear deformation and significant structural degradation at greater tunnel depths highlight the need for targeted strengthening measures, particularly in vulnerable areas such as tunnel crowns, invert arches, and footings. The findings from this research provide crucial references for the seismic assessment and structural design of slope-tunnel systems in earthquake-prone regions, significantly enhancing our understanding of interaction mechanisms and dynamic response characteristics. Practical recommendations from this study include considering non-linear seismic responses and localized reinforcement strategies during the design and construction stages of shallow buried twin-tunnel systems traversing slopes. These insights should greatly contribute to improving the resilience and operational safety of tunnel infrastructure under seismic loading conditions.