In order to carry on early warning of geological disasters in construction period of deep foundation pit en-gineering, an improved gray system was used as a predictive tool for predictions on settling of buildings surrounding the pit.Improvements to the gray prediction system included the following parts: the improvements to the initial value of the data series, and the improvements to the background values of gray system model, and the method to convert measured data into a monotonically increasing sequence.The accuracy of model was evaluated by using rel-ative error test, correlation test and posterior error test.Finally, the prediction results of improved gray system was compared with that of original system.It showed that gray system model and improved gray system model have high accuracy in terms of short-term prediction.The improved gray system model has good accuracy on long-term predic-tion.%为了对深基坑工程施工期间地质灾害进行先期预警，使用了改进的灰色系统作为预测工具，对基坑周围建筑物的沉降进行了预测。对于灰色预测系统的改进包括对数据序列初始值的改进和对灰色系统模型背景值的改进，以及实测数据转换为单调增序列的方法。使用相对误差检验、关联度检验和后验差检验对模型的精度进行了评价。最后将改进后的灰色系统与原系统的预测结果进行了对比，结果表明：在短期预测方面，灰色系统模型和改进的灰色系统模型都有很高的精度。对于长期预测，改进的灰色系统模型对中长期预测有很好的精度。
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