Abstract: Comprehensive evaluation provides a basis for the selection of foundation pit support schemes. Set Pair Analysis coupled with TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) is used to build an improved SPA-TOPSIS model. Practicality and representativeness are chosen as principles of the evaluation index set. Combination weighting method is adopted to take the subjective and objective weight of each index into account, and meanwhile the expert’s practice experience and the objective attribute of original data are also considered. The application result shows that the method is feasible, the evaluation result is reliable and reasonable.

Key words: foundation pit, set pair analysis, technique for order of preference by similarity to ideal solution, composite weights, application