浅埋偏压小净距隧道衬砌地震应变规律研究

Study on Seismic Lining Strain Law of Shallow-buried Bias Tunnel with Small Clear Distance

设计并制作了比例为1∶10的浅埋偏压小净距隧道物理试验模型,并开展了大型振动台试验,研究了地震波类型及加速度激振峰值对浅埋偏压小净距隧道衬砌应变响应规律的影响。研究结果表明:在0.1g与0.2g的工况下,衬砌的拉应变变化趋势较为相近且平缓;在0.4g与0.6g的工况下,衬砌的拉应变变化趋势较为相近且波动较大。拉应变受地震波类型的影响较小,而受地震波加速度激振峰值的影响较明显且随着加速度激振峰值增大而增大。在衬砌拱脚及拱顶处会产生较大的拉应变。衬砌的拉应变大于压应变且拉应变的变化趋势较为明显。在不同的加载波类型和不同的加速度激振峰值作用下,应变变化趋势呈现明显的非线性变化特征。研究结果可为浅埋偏压小净距隧道的设计与建设提供有益参考。

A physical test model of shallow-buried bias tunnel with small clear distance of 1：10 was made to perform the large-scale shaking table tests. Influences of seismic wave type and acceleration excitation peak value were studied on the lining strain response laws of shallow-buried bias tunnel with small clear distance. The results show that under the conditions of 0.1 g and 0.2 g, the tension strain variation trends are similar and gentle, but under the conditions of 0.4 g and 0.6 g, the tension strain variation trends are similar with large fluctuation. The tension strain is less affected by the type of seismic wave, but it obviously increases with the increase of the acceleration excitation peak value. Larger tension strain can be generated at arch foot and arch crown of lining. The tension strain of lining is larger than compression strain, and the change trend of the tension strain is more obvious. Under different types of seismic wave and different acceleration excitation peak values, changing trend of strain presents obvious nonlinear characteristics. The research results can provide useful reference for the design and construction of shallow buried bias tunnel with small clear distance.