水深及衬砌弹性模量对水工隧洞动位移的影响

Analysis of Seismic Dynamic Displacement of Hydraulic Tunnel Affected by the Depth of Water and the Lining Elastic Modulus

考虑水工隧洞在不同的输水深度和衬砌弹性模量条件下的地震动力响应变化规律,对研究水工隧洞在地震激励作用下的变形破坏机制非常重要。根据黏弹性人工边界和地下结构抗震计算理论,选取合理的材料参数和模型边界条件,应用ANSYS建立了某水工隧洞的三维有限元模型,对其施加拟合后的人工地震波,并采用瞬态分析法计算了隧洞结构模型在不同输水深度和衬砌弹模下的动位移变化规律。结果表明:输水深度在一定程度上可以改变水工隧洞抗震性能,水工隧洞随着输水深度的增加,水平位移和竖向位移受影响的程度有明显的区别,水平位移先增加后减少,竖直位移无明显规律;衬砌弹性模量能够在很大程度上影响水工隧洞的抗震性能,各参考点的水平位移随着衬砌弹性模量的增加呈现出先减小后增加,大部分参考点的竖直位移都在增加;水工隧洞在地震发生后其拱顶及拱肩受影响程度比较大,在水工隧洞设计中应特别关注。

Considering the importance of varying patterns of seismic dynamic responses of hydraulic tunnel under the different depths of water and lining elastic modulus for the study of deformation failure mechanism of hydraulic tunnel under the effect of seismic dynamic responses , in this paper , reasonable material parameters and model boundary conditions were selected based on the underground structure seismic calculation theory , the finite element software ( ANSYS ) was applied to establish the three-dimensional finite element model for a hydraulic tunnel and fitted artificial seismic waves were also applied to it. Seismic response of hydraulic tunnel in different depths of water and the lining elastic modulus had been calculated by transient dynamic analysis. It turns out that the depth of water can change seismic performance of hydraulic tunnel to some extent. With the increase of the depth of water , there is an obvious distinct between the horizontal displacement and vertical displacement. For instance , the horizontal displacement increases at first and then decreases , while there is no apparent rule for the vertical displacement. The seismic performance of hydraulic tunnel is largely affected by lining elastic modulus , so with the increase of lining elastic modulus , the horizontal displacement at every reference point increases at first and then decreases , while the vertical displacement increases all the time in major reference points. The influence of earthquake is mainly distributed on the vault and the spandrel of hydraulic tunnel , therefore , more attention should be paid on in the design of hydraulic tunnels.