堆积层斜坡地震响应规律的虚拟试验分析

Virtual Tests for Seismic Response Regularity of Slope Covered by Deposits

运用平面快速拉格朗日有限差分计算方法,研究了地震作用下攀田高速公路望江岭隧道出口堆积层斜坡的动力响应规律,就地震加速度幅值、频谱特性等相关参数对斜坡动力系统的影响进行了敏感性讨论,并进一步将虚拟试验计算结果与原型现场实测数据进行对比分析。结果表明:(1)输入地震加速度幅值特别是峰值强度的提高不仅对堆积体累积塑性变形具显著影响,且于堆积体稳定状态具有较强的扰动效应;(2)不同地震波动激励下,堆积层斜坡水平位移变化规律较大程度上依赖于所输入动载荷的固有属性;(3)峰值强度为0.49m/s2的Loma Prieta水平地震加速度作用20s末,数值虚拟试验结果与现场测斜同震相对位移在量值与分布趋势方面均较为接近。

Coseismic response regularity of the slope covered by deposits at exit of the Tianfang end of Wangjiangling tunnel of Panzhihua-Tianfang Motorway are studied with the 2-D fast Lagrangian finite difference method numerically,and the effects of amplitudes and spectrum characteristics of the input horizontal accelerations are also investigated,based on above mentioned researches,the relevant results of virtual tests are furthermore compared with the field monitoring data of the archetype slope.Simulation results reveal that：（1）both the cumulative plastic deformation and globe stability condition of the deposits are very sensitive to the amplitude especially the peak value of the input horizontal acceleration;（2）evolution rules of horizontal displacements of the deposits depend to a great extent on the intrinsic attributes of the earthquake loads;and（3）after continuous loadings of the Loma Prieta horizontal acceleration with peak value of 0.49 m/s2 and duration of 20 s,the coseismic relative longitudinal displacements corresponding to inclinometer borehole J3 in the numerical simulation are quite close to the field monitoring results in both the magnitude and distribution pattern.