白鹤滩和乌东德库区蓄水前形变分析

利用白鹤滩和乌东德库区2018～2019年两期最新地壳形变监测资料对两个库区在监视期的形变特征进行分析，其中水准和重力资料采用相对基准分析法，谷宽和跨断层测距资料采用投影面相对坐标分析法。结果表明：1）白鹤滩库区上游左岸中部存在16 km范围的沉降区，乌东德库区上游右岸水准支线所在地区隆升较大，两个库区其他地区均相对稳定，垂直形变量均小于5 mm；2）两个库区重力场变化基本平稳，无显著性异常变化，个别测点重力值变化较大是周围环境改变导致；3）两个库区4个谷宽网各点的相对坐标变化均不大，但4个谷宽网均显示相对收缩，量值在1~2 mm；4）两个库区6处跨断层场地中有5处比较稳定，监视期间断层无显著垂直活动和水平活动迹象，乌东德库区洛佐场地监视区断层两侧存在一定的差异性垂向运动并伴随水平向挤压运动。该结果可为水库蓄水后形变以及水库诱发地震的研究提供背景参考。

Improvement of GM(1,1) Power Model and Its Application on Settlement Prediction

The GM(1,1) power model can be used for the prediction of settlement that tends to be stable or has a trend of S-type. However, the GM(1,1) power model has some shortcomings, including the inherent defects of grey modeling, no applicability for non-equal interval data, and the complexity of solving parameters. In combination with the power function transformation and the unbiased GM(1,1) model or the unequal interval unbiased GM(1,1) model, we establish the unbiased GM(1,1) power model and the unequal interval unbiased GM(1,1) power model. Based on the Matlab program, we take the minimum relative mean error of the fitting results as the optimization objective, and advance the solving method of optimization parameters. Meanwhile, we propose an alternative method of Origin fitting function SRichards2. The application results of engineering examples show that the two methods have a good fitting effect and can be used in settlement prediction. Considering the application effect and the modeling characteristics of the two methods, we recommend the Origin fitting function SRichards2 is recommended for manual data processing, and the unbiased GM(1,1) model and non-equal interval unbiased GM(1,1) model for special optimization objectives or automatic monitoring design.