Assessment Method Of Resources And Environmental Carring Capacity Of Urban Underground Space And Its Application

The resource development and utilization of underground spaces is an important means to cope with realistic problems related to the constraints on urban development scale,the optimal urban space layout,and urban traffic congestion.It is therefore of great practical significance and scientific value to carry out research on the resource evaluation methodology of urban spaces and its application.Using both qualitative and quantitative approaches,this paper establishes a scientific,comparable,hierarchical,operable “double evaluation” methodological system targeting the resource environmental carrying capacity and development suitability of urban underground spaces in an effort to reveal the coupling effect of the resource environmental carrying capacity and development suitability of these spaces.Taking Tonghu New Area as an example,first,single-factor resource environmental carrying capacity measurement and carrying state evaluation of urban underground spaces are performed;then the overall resource environmental carrying capacity and development suitability of underground spaces are investigated with a view to providing scientific reference for urban underground space development and land space planning.The highlights are as follows:(1)Multi-factor geological characteristics affecting the resource environmental carrying capacity of underground spaces are analyzed.Based on multi-source heterogeneous data,the groundwater type,aquifer spatial distribution,aquifer hydraulic connection,groundwater recharge-runoff-discharge relationship,and groundwater dynamics in the study area are analyzed;constraints on the resource environmental carrying capacity of underground spaces—undesirable engineering geologies,geological disasters,water and soil pollution and the like—are examined.The undesirable engineering geologies include undercompaction of weak layers,uneven carrying capacity in the soft-hard contact zones,and poor stability in the crushed zones.The geological disasters mainly include collapses and landslides,typically occurring in monadnock and plain areas during the heavy rainfall period from April to September.Environmental pollution,primarily water pollution,has already caused serious damage to the wetland ecosystem of the study area.(2)A methodological system for evaluating the resource environmental carrying capacity and development suitability of urban underground spaces is preliminarily established and integrally applied.Single-factor evaluation is conducted on environmental geological conditions,water and soil geochemistry,geological disasters,and sensitive geological bodies.According to the overall resource environmental carrying background and state and the principle of urban underground space development,the overall resource environmental carrying capacity of urban underground spaces is integrally evaluated by incorporating the relationship between the anticipated urban development scale and the population size,and the demand of urban underground space development.(3)The coupling effect of the resource environmental carrying capacity and development suitability of urban underground spaces is quantitatively revealed.Quantitative measurement is made with 23 indicators in the five subsystems of the surface and underground systems—geological environment,water and soil environment,sensitive geological bodies,groundwater resources,and mineral resources—to evaluate the bidirectional grade of the development suitability of underground spaces,which reveals that the overall resource environmental carrying capacity of underground spaces in the study area is relatively high and the carrying state is surplus on the whole.The results show that the coupling effect of resource environmental carrying capacity and development suitability mainly exists between the geological factors of underground spaces,between the geological factors of underground spaces and underground buildings,and between the geological factors of underground spaces and surface buildings.