砂卵石大三轴试验及在边坡地形效应中的应用

Study on large-scale triaxial test of sandy pebble soil and its application to the slope topography effect

汶川地震发生后,颠覆了砂卵石在动力作用下表现稳定这一传统认识,拟利用大型土工静、动力三轴试验,给出砂卵石的静力、动力特性参数,结合一个典型场地剖面,运用二维等价线性时程响应分析法,研究了场地地震动放大效应。结果表明,含砂卵石的场地具有地震动放大效应,随着边坡高度的增加,加速度、速度和位移均产生了放大作用。地震动反应谱由于受到砂卵石层的影响,使其高频成分非常丰富,放大作用显著。反应谱低频部分随观测点的高度变化,衰减指数差别显著,位置越高,加速度峰值越高,衰减越快,反之亦然。这些试验数据和研究结果,可为含砂卵石地区的工程抗震和边坡稳定性评价等工作提供参考,具有一定的工程意义。

After Wenchuan earthquake in 2008, the tradition knowledge which the sandy pebble soil is stable under dynamic loads is subverted. The static and dynamic characteristic parameters are provided by dynamic triaxial tests in laboratory. Based on typical site including the sandy pebble soil, the site seismic response analysis is researched by dynamic finite element method of two dimensions linearly equivalent. The results show that there are seismic am- plification effects at the slope including sandy pebble soil, the acceleration, velocity and displacement increases with the increase of slope height gradually. Moreover, because of the sandy pebble soil in the slope site, the high frequency of response spectrum is much more abundant and its amplification is very obvious. The low frequency of response spectrum result is effected by the height of observation points. The height is much more higher, the peak acceleration is much more increased, the attenuation is faster. In this paper, all the test data and results can be re- fer to the anti-seismic of building and stability evaluation of slope site. It also have certain engineering significance.