强震作用下核电厂顺层软岩高边坡组合支挡结构抗震性能研究

在综述国内核电厂高边坡案例研究进展的基础上,以某核电厂含泥化夹层顺层软岩高边坡为例,探讨应用多种方法综合分析其在地震作用下的动态放大效应、抗震性能和加固效果的分析思路。首先,基于典型二维计算剖面,采用拟静力法对边坡进行初步加固设计;然后,基于振动台试验和数值计算,研究边坡动态放大效应、支挡结构的动力响应和抗震性能,探讨边坡抗震参数优化取值。研究结果表明:(1)原位边坡坡面的加速度放大系数随高度增加而增大,且泥化夹层饱水后的放大系数要大于饱水前,水平向最大值为1.90;(2)加固后边坡动态放大系数显著降低,水平最大放大系数为1.31,垂直向基本为1.0,锚索抗滑桩以下边坡基本不存在放大效应,说明软岩高边坡采用锚索抗滑桩和锚索框架抗震性能较好;(3)PGA=0.21g时,边坡整体抗震性能较好,仅最顶部锚杆和中部锚索受力超过设计锚固力,分别超过设计值的20%和5%,适当加强即可;(4)数值计算得到的加速度放大系数分布规律与振动台试验结果较为一致,且两者得到的坡顶加速度放大系数也十分接近。研究成果可为核电厂软岩高陡边坡抗震安全评价和工程设计提供技术支持。

Seismic Behavior of the Composite Retaining Structures inCase of Nuclear Power Plants in High Soft-RockSlopes under Strong Earthquakes

Based on the progress of the case study conducted on high slopes of domestic nuclear power plants, a high soft-rock slope that interacts with clay in a nuclear power plant has been selected as an example in this study to comprehensively analyze the dynamic amplification effect, seismic performance, and reinforcement effect under earthquake action using various methods. Initially, we use a pseudo-static method to obtain a preliminary reinforcement design of the slope. Next, we analyze the dynamic amplification effect of the slope as well as the dynamic response and seismic performance of the retaining structures based on the shaking table test and numerical calculation results. Furthermore, we discuss the optimization value of the seismic parameters of the slope. The research results denote that (1) the acceleration amplification factor of the in situ slope increases with an increase in height, the magnification factor of mudded intercalation after saturation is greater than that before saturation, and the maximum value of the factor in the horizontal direction is 1.90; (2) the dynamic amplification factor significantly decreases after reinforcement, and the maximum factor in the horizontal direction is 1.31, whereas the maximum factor in the vertical direction is 1.0 (note:no amplification effect in the slope below the anti-slide pile with the anchor cable indicates that the seismic performance of high soft-rock slope is good when using an anti-slide pile with an anchor cable and the anchor-cable framework); (3) the overall seismic performance of the slope is good for PGA=0.21g, and only the force value of the anchor cables at the top and middle parts of the slope exceed the design value by up to 20% and 5%, respectively; and (4) the acceleration amplification factor distribution obtained via numerical calculations is in good agreement with the shaking table test results. Furthermore, the acceleration amplification factors obtained by the two methods are very close. The research results can provide technical support to conduct seismic safety evaluation and obtain engineering design for high and steep soft-rock slopes in case of nuclear power plants.