Study On 3D Geological Suitability Evaluation For The Development Of Underground Space In Binhu New District,Hefei City

With the increasing development of cities,the development and utilization of urban underground space is restricted by geological conditions on the one hand,and on the other hand,it will cause a series of environmental geology,engineering geology and hydrogeology problems.Therefore,before large-scale development of urban underground space,it is necessary to evaluate and analyze the geological suitability of urban underground space development,so as to provide decision-making basis for urban planning and engineering construction.Binhu New Area is one of the key development areas in Hefei in the future,and there is a strong demand for underground space development.Therefore,in this paper,the implicit 3D geological modeling method is used to establish the 3D geological model of Binhu New Area in Hefei;Based on the analysis of the geological environment influencing factors of urban underground space development in the area,combined with the collected data,the appropriate evaluation factors are selected,and the evaluation factor standard system is divided according to the previous research,and the three-dimensional evaluation model is constructed;Through the three-dimensional spatial analysis of each evaluation factor,the three-dimensional evaluation data set is established;Then,the subjective and objective weights of each evaluation factor are calculated by AHP and entropy weight method,and the reasonable weights of evaluation factors are obtained by optimizing the weights and combining the subjective and objective weights;Finally,the multi-level index superposition method and fuzzy comprehensive evaluation method are used to evaluate the geological suitability of underground space development in the study area.By comparing the evaluation results of two different comprehensive evaluation methods,the geological suitability of underground space development in the study area is comprehensively analyzed and evaluated(1)The geological suitability of the overall underground space development in Binhu New Area of Hefei city is relatively suitable.The geological environment of underground space development in shallow area is poor;However,due to the influence of underlying soft soil and aquifer in some areas,it is difficult to develop underground space and the cost of development rises;The geological environment is most suitable for the development and utilization of underground space without considering the factors such as the increase of excavation cost caused by the deepening of depth,but the influence of structural factors such as fracture should be avoided in the excavation of deep area.(2)Compared with the previous two-dimensional evaluation results,it can significantly improve the depth direction resolution of the evaluation results.At the same time,based on the three-dimensional evaluation results,it can further obtain the specific depth,depth and depth information according to the needs The evaluation results in a specific scope improve the practicability of the evaluation results.(3)By comparing and analyzing the three-dimensional comprehensive evaluation results obtained by multi-level index superposition method and fuzzy comprehensive evaluation method,it can be seen that the development suitability of shallow,medium and deep areas evaluated by the two methods is basically the same,but the fuzzy comprehensive evaluation method is more sensitive to the identification of unsuitable areas.In general,the comprehensive evaluation results can provide a reasonable reference for the fine planning and sustainable development and utilization of urban underground space.