## 4 Discussion
Yellow indicates that there is a possibility of unsafe distortion, and only on-site operation is required to pay attention to the changes at all times, and the changes are notified at daily meetings. (2) Analysis of single data source early-warning results and multi-data source fusion early-warning results. From Figure 9a-f, the differently colored bars represent the different methods of obtaining early-warning results. The average early-warning accuracy can be obtained by averaging the early-warning accuracies of different monitoring points. Similarly, the average false alarm rate and the average missed alarm rate can be obtained as in Figure 9g. It can be seen that a single source of information has a missed alarm rate of up to 23.8%, a false alarm rate of up to 22.9%, and an accuracy rate of no more than 68.8%. Traditional D-S has a missed alarm rate of 12.4%, a false alarm rate of 13.8%, and an accuracy rate of 73.8%. The improved method in this paper has a missed alarm rate of 7.1%, a false alarm rate of 8.3%, and a correct rate of 84.6%. It is clear that the method proposed in this paper has the highest accuracy rate and the lowest missed alarm rate and false alarm rate. The next best performing method is the traditional D-S method, followed by the single source of information method. It can be seen that the fusion of multi-source information for early warning has a higher accuracy rate compared to a single data source. It can be seen from Figure g that among the single information sources, the early-warning accuracy of the surface subsidence information source is the highest, which is 68.8%. The early-warning accuracy of groundwater level information source is the second, which is 60.4%. The early-warning accuracy of pile horizontal displacement information source is the lowest, which is 53.3%. The reason is that the horizontal displacement of the pile is often the result of deeper reasons such as soil instability, support failure, and groundwater action. When the displacement increases significantly, these deep problems may have developed to a more serious degree. Therefore, there is a certain lag in the early warning through the horizontal displacement of the pile. The accuracy of multi-source information fusion early-warning method is higher than that of single information source. In the early warning of multi-source information fusion, the early-warning accuracy of the improved method is 84.6%, which is 10.8% higher than that of the traditional DS method. This is due to the fact that the traditional method does not process the high conflict evidence, while the improved method performs the first type of conflict adjustment and the second type of conflict correction on the conflict evidence, thus reducing the contradiction between the evidence and improving the accuracy after fusion. Figure 9: \(Cont.\)  
As the pit excavation process involves many risk factors, a single data source, although it realizes risk early-warning to a certain extent, often fails to reflect the actual situation of the whole pit excavation. However, the multi-source data fusion method takes into account the characterization information from multiple data sources and provides a more comprehensive understanding of pit deformation, which can reduce the uncertainty and ambiguity associated with a single data source, thus improving the early-warning accuracy. However, traditional D-S performs poorly when dealing with multi-source high-conflict evidence, and it can even produce the exact opposite result. Therefore, the improved fusion early-warning method proposed in this paper can better solve the problems of low credibility of a single information source and the failure of fusion of highly conflicting evidence from multiple sources. For actual engineering, the early-warning accuracy of single information source methods or traditional D-S methods is low, which can easily cause collapse accidents.