Evaluation of slope stability of open pit based on factor space

Abstract

Objective The factors affecting the stability of an open pit slope are complex and fuzzy. Hence, it is difficult to evaluate the stability through mathematical and mechanical analysis methods. Methods According to the actual engineering characteristics and in-situ investigation of an open pit, four first-class evaluation indexes including landform, geological structure, rock mass properties and occurrence environment and 17 second-class evaluation indexes were determined. The stability evaluation model of open pit slope based on factor space is established. Firstly, the analytical hierarchy process(AHP) and entropy weight method are used to calculate the subjective and objective weights, and the combined weights of the factors affecting the stability of the open pit slope are given. Then, the unascertained measure theory is used to construct the measure function, calculate the single factor measurement matrix to evaluate the slope stability, reduce the dimension of the factor space through factor synthesis, and generate the combined factor measure vector. Finally, the stability of the open pit slope is evaluated through the confidence recognition criteria. Taking the typical slope profile of the eastern slope of Qidashan open pit iron mine as an example, the factor space evaluation results are compared with the calculation results of the limit equilibrium method and the finite difference method, and the reliability of the slope evaluation method is verified. Results The results show that the evaluation results of factor space model are basically consistent with the results obtained from the field investigation, and are consistent with the calculation results of limit equilibrium method and finite difference method, which verifies the accuracy and scientificity of the established factor space evaluation model. Based on the comprehensive analysis of the factor space evaluation results and the calculation results of other methods, four slope profile protection and treatment suggestions are given. Conclusion The factor evaluation model simplifies the process of slope stability evaluation, improves the accuracy of the evaluation results of the model, and can provide a reference for the stability evaluation of an open pit slope with similar geological conditions.

Keywords

• factor space
• open pit
• slope stability evaluation
• unascertained measure theory