考虑基质吸力作用的Newmark改进模型在地震滑坡风险评价中的应用

传统的Newmark模型常对地下水位以上由负孔隙水压力提供的部分抗剪强度忽略不计，这对于滑动面的主要部分处在地下水位以下时较为合理，但对地下水位很深或考虑出现浅层滑动的坡体，其计算结果过于保守。因此，文章将Newmark累积位移模型扩展至非饱和土力学领域，在考虑基质吸力作用的基础上，改进了Newmark模型计算公式。分别利用Newmark传统模型和改进模型对甘肃礼县幅区域内的地震滑坡进行易发性分区，并在此基础上分别开展50年超越概率10%情况下的地震滑坡危险性分区和风险评价，最后利用ROC曲线对评价结果进行验证和比较。结果表明:改进模型所得易发区和危险区的计算结果明显优于传统模型计算结果；改进的模型所得风险区的计算结果虽然改进效果不明显，但仍优于传统模型计算结果。由于考虑基质吸力作用的Newmark改进模型充分发挥了基质吸力的贡献，使得计算结果更为合理，研究成果可为相关地区开展地震滑坡易发性分区、危险性分析和风险评价提供新的参考。

Application of Newmark improved model considering matrix suction in earthquake landslide risk assessment

The traditional Newmark model often neglects the partial shear strength provided by the negative pore water pressure above the groundwater level. This is reasonable for the main part of the sliding surface below the groundwater level. However, the calculation results are too conservative for slope with a deep groundwater level or considering shallow sliding. Therefore, the Newmark cumulative displacement model is extended to the field of unsaturated soil mechanics in this paper. Based on the consideration of matrix suction, the Newmark model calculation formula is improved. The Newmark traditional model and the improved Newmark model are used to classify the susceptibility zoning about the earthquake landslide of the Lixian county map of Gansu Province. On this basis,the hazard zoning and risk assessment of earthquake landslide under 10% probability in 50 years are carried out respectively. Finally, ROC curve is used to verify and compare the evaluation results. The results show that the calculated results of the susceptibility areas and the hazard areas obtained with the improved model are obviously better than those with the traditional model, and the calculated results of the risk areas obtained with the improved model are better than those with the traditional model although the improved results are not obvious. The improved Newmark model, which takes the effect of matric suction into account, gives full play to the contribution of matric suction and makes the calculation results more reasonable. The research results can provide a new reference for earthquake landslide susceptibility zoning, hazard analysis and risk assessment in relevant regions.