基于汶川地震强震动记录的边坡永久位移预测模型

Predictive models for permanent displacement of slopes based on recorded strong-motion data of Wenchuan Earthquake

边坡的永久位移为边坡工程的抗震设计和坡体稳定性判识提供了可靠的依据。利用汶川地震时记录到的大量强震动记录,建立了基于临界加速度比、Arias强度和地震剩余强度的永久位移预测模型。通过能量法将实测边坡位移转换为无支护结构的边坡永久位移,并利用其检验了模型的有效性。文中提出的3种位移模型与回归数据具有良好的相关性,基于地震剩余强度的模型拟合效果最佳,说明永久位移与地震剩余强度具有强相关性;以临界加速度比为参数的模型简单实用;以Arias强度为参数的模型判定系数和预测精度均较差。研究结果表明,由于记录台站的当地效应,基于强震动记录回归的永久位移模型具有区域相关性。文中提出的模型可为四川及其邻近省份的西部山区区域地震滑坡风险评价、震后滑坡灾势评估以及具体边坡工程地震稳定性的快速预估提供依据。

The permanent displacement induced by earthquakes can be regarded as an effective criterion for the stability estimation and anti-seismic design of slopes. Based on a large number of strong-motion records from Wenchun Earthquake, three kinds of regression models for predicting the permanent displacement in terms of （1） the critical acceleration ratio, （2） the Arias intensity and the critical acceleration ratio, and （3） the residual seismic intensity are established. Their validities are examined by the displacements converted from the measured ones of reinforced slopes by means of the energy method. These equations are well constrained and fit the data well, among which the equation in terms of the residual seismic intensity fits best, indicating that the permanent displacement has a close relationship with the residual seismic intensity. The model in terms of the critical acceleration ratio is brief but practical, and that in terms of the Arias intensity has a low value of R2 and prediction precision. The results show that the models developed based on strong-motion records have zone dependence because of the site effect of stations. The proposed models can be used to generate a regional-scale seismic landslide hazard map, to provide the assessment of landslide distribution after earthquakes, and to accelerate preliminary screen of specific sites.