动荷载下土石不均匀地基土体强度对综合管廊力学响应的影响

Effect of soil strength on mechanical response of integrated pipe gallery in uneven soil-rock foundation under dynamic load

综合管廊地下浅埋结构在穿越土石不均匀地段时管廊结构受力会受到不利的影响,因此,以室内模型试验为基础,通过ABAQUS三维有限元模拟来探究动荷载下土石不均匀地基土体弹性模量变化对地基承载力、管廊结构受力以及管廊应变的影响。试验结果表明:上部荷载不变时,地基沉降量随动荷载循环次数的增加逐渐增大;荷载次数相同时,地基沉降速率随荷载增加而增大;管廊顶板加速度随着振次的增加逐渐趋于稳定,但是随着土石不均匀地基之间土体弹性模量的减小,管廊加速度趋于稳定的难度加大,同时顶板加速度的震荡幅度增大对管廊结构十分不利;管廊顶板的动应力幅值与动应变峰值呈现出随土石不均匀地基土体弹性模量降低逐渐增大的趋势,其中管廊顶板动应力幅值的大小与动应力的大小呈线性相关,且与土石不均匀地基土体弹性模量无关。

When the shallow underground structure of integrated pipe gallery passes through uneven soil-rock area,the stress on the pipe gallery structure will be adversely affected.Therefore,this paper studies the effect of the change of soil elastic modulus of the uneven soil-rock foundation on foundation bearing capacity,pipe gallery structure stress and pipe gallery strain under dynamic load through ABAQUS 3-D finite element simulation based on the indoor model test.The test results show that the settlement of foundation increases with the increase of dynamic load cycles when the upper load is unchanged;and the settlement rate increases with the increase of load cycles when the upper load is the same;the acceleration of the roof of the pipe gallery tends to be stable with the increase of vibration times,but with the decrease of the elastic modulus of the soil of the foundation,it becomes more difficult to stabilize the acceleration,and the increase of the vibration amplitude of the roof acceleration is very unfavorable to the structure of the pipe gallery;the dynamic amplitude and dynamic strain peak values of the roof of the pipe gallery increase gradually with the decrease of the elastic modulus of the soil in the foundation,but the dynamic stress amplitude of the roof of the pipe gallery is linearly related to the dynamic stress,and has nothing to do with the elastic modulus of the soil in the uneven soil-rock foundation.