Abstract
The stability of ground surface along tunnels in karst terrain is influenced by complex factors, among which the karst features are the significant ones. Under the influence of karst, the ground surface along tunnels is very easy to collapse, thus causing great casualties and economic losses. To provide guidance for maintaining the stability of ground surface along tunnels, an analysis system is proposed for assessing the stability of ground surface along tunnels in karst terrain based on an improved fuzzy comprehensive evaluation. Based on the case analysis of ground collapse along tunnels in karst terrain and the review of the related researches, the evaluation index system for ground surface stability assessment was established. The ridge-shaped membership functions were constructed to calculate the membership degree for the evaluation indices. The comprehensive weighting method combining the Fuzzy Analytical Hierarchy Process and correlation analysis was applied to determine weights for evaluation indices. And the ground surface stability level was recognized based on the maximum membership principle. The proposed assessment system was applied to assess the ground surface stability along the tunnels of Guiyang Metro Line 1, and the assessment results agreed well with the regional ground collapse history, verifying the effectiveness and reliability of the assessment system. Combining with the assessment results, a series of measures were conducted to promote the ground surface stability before tunnel excavation. This system provides a valuable tool for assessing and guiding to improve stability of the ground surface along tunnels in karst terrain.
Highlights
During tunneling in karst terrain, the excavation disturbance can cause instability of karst caves and leads to the ground surface collapse
More and more efforts have been made in the development and utilization of underground space, and thousands of tunnels have been constructed in karst terrain all over the world, resulting in the fact that hundreds of ground collapses caused by tunnel construction have happed [8,9,10]
The stability of up to 120000 m2 buildings on the ground was threatened, and more than 260 households were forced to relocate [11]. Another example is that the ground collapse caused by Wuhan metro tunnel excavation in the karst areas resulted in four people falling and died in the collapse pits and millions of RMB of economic losses
Summary
During tunneling in karst terrain, the excavation disturbance can cause instability of karst caves and leads to the ground surface collapse. Based on cases analysis of ground collapse in karst terrain and review of the related researches [14, 15, 28, 34,35,36,37,38,39], the following ten factors, PBK, FSC, TBC, SBC, GHC, DGB, width of fault and its influence zone (WFI), structural features of fold (SFF), depth of the proposed tunnel (DPT), and groundwater table change caused by excavation of the proposed tunnel (GCE), were selected to access stability of ground surface along tunnels in karst terrain. Considering the characteristics of the evaluation indices of stability of ground surface along tunnels in karst terrain, the ridged membership function was applied to calculate the membership degrees for evaluation indices in this research [41].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
