廢棄坑道之地盤下陷潛在災害調查主要研究對象為地下採礦坑道、鐵公路的隧道以及軍事隧道等等，因其這類資訊取得可及性極低、地下地質資料的缺乏與專業性等條件的限制，災害潛勢的調查與評估顯得相當缺乏。由於這類廢棄坑道常會引起地表變形（surface deformation）或地盤下陷（ground subsidence）等災害，因此對地上建物與民眾安全具有潛在不確定性之災害影響。本計畫工作在經過97年度北北基都會區之調查與災害潛勢評估之初步結果，首次引進多項技術之結合，提供災害潛勢之驗證。其包括多下陷槽之數學模式結合了GIS-3D空間分析、CMRR岩石力學分類的技術提供了災害潛勢高低之比較因子、D-InSAR影像分析技術提供大範圍地盤下陷趨勢之判釋，以及建立專家安全評估模式等等。目的是希望透過多方技術的整合來逐步建立台灣地區地下坑道所引發之地盤下陷災害相關資訊，從而建立適用於台灣之災害潛勢分析模式。而98年度計畫之主要調查區域為台北縣地區（汐止市、萬里鄉兩區除外）約7處，另於97年度工作團隊認為有必要持續調查之重要採掘跡4處，共計11處重點調查採掘跡。經由上年度之工作執行經驗中，初步證明了多下陷槽結合GIS-3D空間分析輔以CMRR岩力分類可以在地盤下陷災害之潛勢範圍界定上，提供一個較快且合理之方法與分析模式。而D-InSAR以東運瓷土礦在民國93~97年間數次地表塌陷之案例分析成果亦可判釋出地盤下陷範圍之趨勢與多下陷槽推估者範圍吻合。另外也針對地盤下陷災害之安全評估流程進行專家評估模式之探討。上述方法將於本年度中持續精進、驗證以及修訂災害潛勢之分級與評估流程，期能建立一套適用於台灣地區因廢棄坑道引發之地盤下陷災害潛勢評估模式。此外，並將本計畫的成果應用在地質法草案(96.5.2)第六條「中央主管機關得將有發生地質災害之虞之地區，公告為地質敏感區」，做為此一類地質敏感區劃設的重要參考。 In Taiwan, the ground subsidence hazards could be caused by the abandoned tunnels（adits or shafts）excavated underground around coal mine area. The locations of underground excavations did not be identified clearly, nor did the geospatial relationship in subsurface. So the main purpose of this project is to establish the model of ground subsidence hazard and to define the potential risk area. According to experience from last year works, the locations of hazardous cases are coincided with the prediction of multiple subsidence troughs model. The geomechanical property of roof rocks classification calculated from the CMRR discriminate function is ranged from moderate to weak. But the field data collected from outcrop and core drilling show that the rock engineering property might be higher than CMRR predicted. This problem should be modified in this year work. In the other methodology of ground subsidence monitoring, the result of D-InSAR analysis shows well comparison with subsidence model in the detected area, Tonyung clay mine area in Chung-Ho City of Taipei County, Besides, we also make a brief manual for abandoned underground mine inventory and risk assessment. The Fedral Highway Administration of Dept. of Transportation, U.S. has been built up the methodology in field investigation and the risk evaluation in 1999. This manual also should be modified during the last two year. There is so few reports or discussions of the ground subsidence in Taiwan. The result can give us a better understanding in the mechanism of subsidence occurred, also an advanced interpretation of subsidence how they proceeded. And such the risk assessment of subsidence hazards in those abandoned mine areas could provide important information for the government’s policies, especially in the land-use aspect.
