论文部分内容阅读
加速度响应规律是解释滑坡震害、合理确定地震影响系数的基础。为此,设计完成50倍重力加速度条件下的堆积型滑坡离心振动台模型试验,模型滑坡放置于600 mm×400 mm×500 mm(长×宽×高)的刚性模型箱内,采用汶川地震清溪台站反演的基岩波作为基底输入,调整其幅值,研究不同强度地震动作用下堆积型滑坡的加速度响应特征及规律。试验结果表明:坡面水平向和竖直向峰值加速度(PGA)放大系数随滑坡的高程增加而增大,趋于坡顶时,增速明显变大,具有明显的高程放大效应;地震动作用下坡面与坡体内部的加速度响应特征明显不同,具有坡面浅表放大效应;滑床岩体自下向上水平向加速度有放大趋势,但与滑坡浅表土体相比,放大倍数则明显减弱;坡顶附近存在显著的波型转换现象;随着输入地震波强度的增大,坡肩PGA放大系数呈现为先增大而后减小的趋势。所得到的成果初步揭示了堆积型滑坡的加速度响应特征,为解释滑坡震害、确定地震影响系数等提供较可靠的依据。
The law of acceleration response is the basis for explaining landslide damage and reasonably determining the seismic influence coefficient. For this purpose, a centrifugal model test of pile-type landslide under 50-fold gravitational acceleration is designed. The model landslide is placed in a rigid model box of 600 mm × 400 mm × 500 mm (length × width × height) The bedrock wave retrieved from Xiuxi station is used as the base input, and its amplitude is adjusted to study the acceleration response characteristics and laws of the accumulated landslide under different intensity ground motions. The results show that the magnification of horizontal and vertical peak acceleration (PGA) of slope increases with the elevation of landslide, and when the slope reaches the top of the slope, the growth rate obviously increases, with obvious elevation effect. The ground motion The characteristics of acceleration response between the downslope and the interior of the slope are obviously different, and have the effect of shallow surface enlargement. The horizontal acceleration of the rock mass from bottom to top has the trend of enlargement, but compared with the shallow surface soil of the landslide, the magnification is obviously And there is a significant wave conversion phenomenon near the top of the slope. With the increase of the input seismic intensity, the PGA amplification coefficient of the shoulder shoulder first increases and then decreases. The results obtained initially revealed the acceleration response characteristics of the accumulative landslide, providing a reliable basis for explaining the landslide damage and determining the earthquake influence coefficient.