针对城市管廊弯折结构对燃气爆炸传播及结构响应影响规律认识不足的问题，开展不同弯折角度条件下管廊内燃气爆炸传播与结构响应特征试验研究。通过集成无人机影像采集、压力监测与半桥应变和应变矩阵等多种手段，实现对燃气爆炸火焰传播过程、超压分布特征以及整体结构和弯折段特征处动态应变响应的多维度同步观测。结果表明： 1)弯折角度的增大会显著抑制火焰传播，最远火焰传播距离从直管工况的0.730 m减小至90°弯折时的0.636 m，并且火焰形态演化阶段提前； 2）弯折结构虽然降低了整体压力峰值，但是会增强局部压力振荡，随着弯折角度的增加，弯折区域压力波动加剧，湍流效应与应力集中现象更为显著； 3）结构变形模式呈现“先以环向膨胀为主，后以轴向拉伸为主”的演变规律，且主变形方向的转换程度随弯折角度增大而减弱，60°和90°弯折角度工况相较于30°工况分别下降25.4%和28.9%。
To address the insufficient understanding of how bent structures in urban utility tunnels influence gas explosion propagation and structural response, an experimental study was conducted on the propagation and structural response characteristics of gas explosions in utility tunnels under different bend angles. An integrated monitoring approach is employed that combines unmanned aerial vehicle image acquisition, pressure measurements, and half-bridge strain and strain matrixes, enabling multi-dimensional and synchronous observation of flame propagation, overpressure distribution, and dynamic strain responses in both the overall structure and the specific bend regions. The results reveal the following: (1) Increasing bend angle significantly suppresses flame propagation, with the maximum flame travel distance decreasing from 0.730 m in straight tunnel conditions to 0.636 m at a 90° bend, and results in earlier occurrences of flame evolution stages. (2) Although the bent structure reduces the overall peak overpressure, it intensifies local pressure oscillations; as the bend angle increases, pressure fluctuations in the bending area become more pronounced, accompanied by heightened turbulence effects and stress concentration. (3) The structural deformation exhibits a sequential pattern, initially dominated by circumferential expansion, followed by axial stretching. Moreover, the degree of this directional transformation diminishes with increasing bend angles, with reductions of 25.4% and 28.9% observed for the 60° and 90° conditions, respectively, compared with the 30° condition.
