黄河阶地特征与地震动参数的相关性研究
Correlation between Characteristics of Yellow River Terraces and Seismic Ground Motion Parameters

在分析已有资料的基础上划分了兰州盆地与建设工程分布密切相关的T0、T1、T2、T3和T4级黄河阶地，建立201个土层地震反应模型。通过一维等效线性化计算和反应谱分析，得出兰州盆地沉积阶地50年超越概率10%地表地震动参数，分析阶地高度和vS≤500 m/s覆盖层厚度特征与地震动参数峰值加速度Am和加速度反应谱特征周期Tg的相关性。表明兰州盆地T0~T2阶地覆盖层厚度与50年超越概率10%Am呈正相关，T3及以上阶地覆盖层厚度对Am增大有明显的减小作用。Tg值随T0~T3阶地覆盖层厚度的增加而变大，当覆盖层厚度进一步变大，Tg值不再同步增大，阶地覆盖层厚度对Tg的影响是有限的，阶地海拔高度与地表50年超越概率10%地震动参数没有关系。
In this paper, the Yellow River terraces T0, T1, T2, T3, and T4 in Lanzhou basin, which are related to the distribution of construction projects, were divided on the basis of existing data, and 201 models of soil layers for seismic response were established. Surface ground motion parameters of the deposit terrace in Lanzhou basin, with 10% probability of exceedance in 50 years, were obtained. The correlation between the deposit terraces and the seismic ground motion parameters, such as peak acceleration Am and the characteristic period Tg of acceleration response spectrum, were analyzed. Results showed that the overburden thickness of terrace from T0 to T2 was positively correlated with the peak acceleration Am with 10% probability of exceedance in 50 years. The overburden thickness of T3 terrace and above had a significant decreasing effect on the increase of Am. Tg value increased with increasing overburden thickness of the terrace from T0 to T3, but no longer increased synchronously when the overburden thickness increased to a certain extent, indicating that the influence of overburden thickness of the terrace on Tg was limited. There was no relationship between elevation of terraces and surface ground motion parameters with 10% probability of exceedance in 50 years