多维地震下考虑地表建筑的土和隧道的振动台试验研究

Shaking table test of a tunnel-soil system considering the influence of surface buildings under multi-dimensional seismic waves

目前关于地下结构–土体系的地震响应研究多为未考虑竖向地震作用和周围建筑的影响。以隧道–土体系为研究对象,考虑10层地表建筑的影响,进行多维地震波作用下的振动台试验,研究隧道和周围土体的动力响应规律。试验结果表明:隧道和土体在双向地震动输入下的地震响应均大于单向地震动输入的响应。随着地震波输入维数的增加,土体的频谱没有改变。土体和隧道在远场地震波作用下的反应较为强烈,但由于近场地震波具有高能量的速度脉冲,随着输入地震动强度的增大,土体和隧道在两种地震波作用下加速度响应的差异逐渐减小。上部结构–桩基的存在导致隧道中间断面与端部截面处应变的不同,与隧道的端部截面相比,中间断面右侧的应变增大,左侧的应变减小。

At present,the seismic response of the underground structure-soil system is mostly studied without considering the vertical seismic action and the influence of surrounding buildings. In this paper,the tunnel-soil system was taken as the objective by considering the influence of a 10-story ground building. The shaking table test under multi-dimensional seismic waves was carried out to study the dynamic response law of the tunnel and soil.The test results show that the seismic response of tunnel and soil under multi-dimensional ground motions is stronger than that under unidirectional ground motions. With the increase of the seismic input dimension,the spectrum of soil does not change. The response of the soil and tunnel under far-field earthquake is strong. Because the near-field earthquake has high-energy velocity pulse,the difference of acceleration response between soil and tunnel under two types of seismic waves gradually decreases with the increase of the input intensity. The existence of surface structure-pile foundation leads to the obvious difference in the strain between the middle section and the end section of the tunnel. Compared with the strain of the end section,the strain on the right side of the middle section increases and the strain on the left side decreases.