Quantitative assessment of engineering geological suitability for multilayer Urban Underground Space

With the increasing exploitation of Urban Underground Space (UUS) increasingly in the cities of developing countries as result of urbanization, the near-surface UUS cannot satisfy the space capacity requirement. Urban Underground Infrastructure (UUI) in multilayer geologies is a solution to meet the need of rapid growing population. However, there is a lack of systematic assessment method for UUS multilayer geological conditions. In this paper, the multilayer UUS exploitation engineering geological suitability evaluation framework is presented. Fuzzy set Analytic hierarchy process and TOPSIS (FAHP-TOPSIS) is employed for the basic layer evaluation. Under the assumption of the Multilayer Number (MN) evolving 1-4, the Transferring Coefficient Matrix (TCM) is constructed as the multilayer effects basis. Combined with the basic layer evaluation and TCM, the UUS Geological Suitability Evaluation (UGSE) results are obtained. Meanwhile the geology analysis details containing the geological investigation, the impact factors and the hierarchy of factors, the fuzzy pair-wise comparison scales, in favor to the impact factors weights list completing, and the factors membership functions are developed to support UGSE. A study case of a Railway station area, in Central China, the UGSE simulation is conducted and the results are discussed. The present UUS geological suitability assessment frame can be applied to a comprehensive UUS suitability evaluation.