Suitability Evaluation Of Underground Space Resources Based On Mathematical Statistics

In recent years,the rapid development of China's economy has accelerated the pace of urbanization.The increase of urbanization rate means that more and more people are crowding into the city,which leads to the shortage of urban resources,and then leads to a series of problems such as traffic jams,lack of construction land,environmental degradation and so on.Human engineering construction activities have a great impact on the geological conditions of the city,so if we want to correctly develop and utilize the underground space resources,and make a reasonable planning of the underground space resources,the first thing is to understand the current situation of the underground space resources and then evaluate the suitability of the underground space resources.In this paper,four typical sections of Yongdinghe and Chaobaihe alluvial proluvial fans in plain area of Beijing are selected as the research objects,and the formation lithology is analyzed by using the drilling data.At the same time,combined with the engineering geological conditions and referring to the relevant geotechnical investigation specifications,the formation lithology is generalized into 12 categories,and the geological modeling software is used to realize 3D geological visualization.On the premise of fully comparing and analyzing the impact of physical and mechanical parameters on the suitability of underground space resources,and drawing on the guidance of experts in relevant fields,7 physical and mechanical parameters are selected from the existing boreholes of 4 typical sections as the indicators of this suitability evaluation.Using statistical calculation method to analyze the measured values of each evaluation index of the suitability,and eliminate the influence of abnormal values on the subsequent evaluation and analysis,so as to provide real and accurate data support for the evaluation of the suitability of underground space resources.Two evaluation methods,AHP + multi factor comprehensive evaluation model and rough set theory + multi factor comprehensive evaluation model,are used to evaluate the suitability of four typical sections with six selected physical and mechanical parameters and generalized lithology as the indicators of this suitability evaluation.Finally,the differences between the results of the two evaluation methods are compared and analyzed based on the actual engineering situation,and the most suitable one is selected The evaluation method suitable for the study area.Based on the above research work,the following conclusions are drawn:(1)The 3D geological modeling software can make good use of the drilling data to present the formation lithology distribution rules intuitively and vividly,which is helpful for us to have a deeper understanding of the formation lithology distribution and engineering geological conditions in an area.(2)The physical and mechanical parameters which are used as the suitability evaluation indexes are tested for outliers by using Leida criterion,Grubbs method and Dixon criterion.Through data calculation and verification,different outliers test methods should be adopted for different sample sizes,so as to ensure the accuracy of eliminating outliers.(3)There are two evaluation methods: comparative analysis AHP + multi factor comprehensive evaluation model and rough set theory + multi factor comprehensive evaluation model The evaluation results of four typical sections,combined with the advantages and disadvantages of the two evaluation methods,and referring to the actual data of existing underground engineering,it is found that the evaluation method of rough set theory + multi factor comprehensive evaluation model can reduce the interference of subjective factors compared with the other method,at the same time,it is more in line with the practical experience of existing underground engineering in the actual excavation construction process,and it is more suitable for Beijing plain Evaluation of underground space resources.