# Suitability Evaluation of Urban Underground Space Development: A Case Study of Qingdao City
## 6 Conclusions  
1. After analyzing six influencing factors, including topography, engineering geological conditions, adverse geological effects and faults, hydrogeology, existing construction conditions, and urban planning requirements, thirteen impact factors were selected as evaluation indicators in the assessment system. These factors include surface elevation, terrain type, surface slope, geological formation type, thickness of soft soil, surface water, aquifer characteristics, landslide and collapse, active faults, depth of building influence, transportation accessibility, population density, and commercial land prices. 2. By introducing a local weighting function into the traditional Analytic Hierarchy Process (AHP), the Variable-Weight Analytic Hierarchy Process (VWAHP) method is obtained. This method allows for timely adjustments of weights based on the characteristics of the evaluation areas when assigning weights to evaluation criteria. A comparison of the weighting results between the two methods reveals that VWAHP can effectively reduce the occurrence of \"neutralization effects\" during the evaluation process. Therefore, in subsequent comprehensive evaluation models, the weight results obtained from VWAHP are used as the weight set in the model. 3. Using both the multi-objective linear weighting function model and the fuzzy comprehensive evaluation model for the suitability assessment of Qingdao's main urban area, a comparison of the evaluation results from the two models reveals that the fuzzy comprehensive evaluation model tends to be more conservative in delineating areas classified as \"highly suitable\" and \"moderately suitable\". Compared to the multi-objective linear weighting function model, the fuzzy comprehensive evaluation model provides more forward-looking and cautionary evaluation results for the development and utilization of urban underground spaces. 4. The evaluation results obtained using the fuzzy comprehensive evaluation model indicate that areas with higher evaluation grades are primarily concentrated in the districts of Shinan and Shibei, as well as in the Xinghua Road and Yong'an Road streets in License District. These areas possess favorable geological and hydrological conditions, along with relatively high economic development benefits. Conversely, lower \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Administrative Region** & **Suitability Level** & **Square Measure (km2)** & **Proportion (\%)** \\ \hline \multirow{4}{*}{Shinan District} & Very suitable & 13.34 & 25.18 \\  & More suitable & 2.92 & 5.51 \\  & Generally suitable & 27.6 & 52.1 \\  & Not suitable & 9.11 & 17.2 \\ \hline \multirow{4}{*}{Shibei District} & Very suitable & 12.66 & 17.85 \\  & More suitable & 6.23 & 8.79 \\  & Generally suitable & 37.54 & 52.94 \\  & Not suitable & 14.48 & 20.42 \\ \hline \multirow{4}{*}{Laoshan District} & Very suitable & 6.12 & 1.32 \\  & More suitable & 11.85 & 2.56 \\  & Generally suitable & 387.69 & 83.84 \\  & Not suitable & 56.74 & 12.27 \\ \hline \multirow{4}{*}{Licang District} & Very suitable & 0.12 & 0.08 \\  & More suitable & 5.38 & 3.56 \\ \cline{1-1}  & Generally suitable & 31.16 & 20.61 \\ \cline{1-1}  & Not suitable & 114.55 & 75.76 \\ \hline \multirow{4}{*}{Chengyang District} & Very suitable & 0 & 0 \\ \cline{1-1}  & More suitable & 0.83 & 0.37 \\ \cline{1-1}  & Generally suitable & 29.59 & 13.18 \\ \cline{1-1}  & Not suitable & 194.04 & 86.45 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Distribution of suitability evaluation levels for medium and deep underground spaces in the main urban area. evaluation grades in most areas of Laoshan and Chengyang districts are attributed to poor engineering geological conditions or lower urban planning demands, resulting in lower evaluation scores. When planning for the development and utilization of underground spaces, areas with higher suitability evaluation grades are designated as priority development zones.