穿越非均匀土体综合管廊振动台试验研究

SHAKING TABLE EXPERIMENTAL STRUDY OF UTILITY TUNNEL IN NON-HOMOGENEOUS SOIL

在建设综合管廊的过程中,难以避免地会穿越水平不均匀土体,此场地不利于管廊的抗震。该研究基于振动台试验,对地震作用下水平非均匀土体与综合管廊的动力变形响应及相互作用进行了系统性研究。深入分析了管廊的土压力增量、加速度、位移和应变,包括加速度峰值沿竖向分布情况以及管廊变形的直接影响因素,发现由于地下结构的存在,土体对加速度放大效应发生衰减;在大震时土体与管廊发生了相对滑移,此现象对管廊的变形产生较大影响;随着加速度的增大,土压力增量分布近似呈抛物线形;结构的柔度比越大,变形越大。基于振动台试验研究了管廊穿越非均匀土体的简化计算方法,通过调整变形比来实现土体分界对管廊变形的影响,为管廊的抗震设计提供参考。

During the construction of utility tunnels,it is inevitable to pass through non-homogeneous soil,leading to adverse effects on the seismic resistance of tunnels.The dynamic deformation response and interaction between the non-homogeneous soil and the utility tunnel under seismic action were systematically studied through a shaking table test.The results of earth pressure increment,acceleration,displacement,and strain were analyzed,including the vertical distribution of the acceleration peak values and the response laws of the direct influencing factors of the tunnel deformation.It is found that the amplification effect of acceleration is attenuated due to the existence of underground structures;the slippage between soil and tunnel occurs during large earthquake,which has a great influence on the deformation of the tunnel;with the increase of acceleration,the distribution of earth pressure increment is approximately parabolic;a larger flexibility ratio of a structure leads to a larger deformation.Based on the shaking table test results,the simplified calculation method of the tunnel through the non-homogeneous soil was studied,and the influence of the soil boundary on the deformation of the tunnel is realized by adjusting the racking ratio,which provides a reference for the seismic design of utility tunnels.