大型山崩之規模與遠距運移及其發生機制摘要遠距滑移之巨型山崩常造成生命與財產的嚴重損失，長久以來，許多學者對於巨型山崩的移動距離較遠此一現像深感興趣，也有許多學者針對滑動體積與滑移距離之關係提出各種假說，然而，關於巨型山崩移動性之相關研究至今仍未能達共識。臺灣不乏巨型山崩之案例，尤其是順向坡滑動，其中，草嶺山崩是最重要的案例，自有歷史記錄以來，草嶺地區至少已發生四次大規模順向滑動。集集地震期間，草嶺附近強震站紀錄到完整的地表振動，其中可能包含了滑脫與撞擊的訊號，另外，草嶺山崩的生還者也完整敘述了滑動與撞擊過程，這些豐富的資料，讓草嶺山崩運動過程以及其力學機制之相關研究具有獨特性。本計畫將利用低至高速旋轉摩擦試驗儀，量測滑動面摩擦係數，實驗將改變剪動速度與正向應力，以獲得速度-位移-正向應力相關之摩擦律。根據此一實驗推導之摩擦律，本研究將推導順向坡滑動岩塊體積與移動距離關係式。另外，本研究將利用滑塊模型，根據速度-位移-正向應力相關之摩擦律，計算集集地震誘發之草嶺山崩其塊體移動之運移過程，透過相關滑脫與撞擊紀錄資料，證明滑動面摩擦律確實是造成順向滑動塊體快速且遠距滑動之主要機制。本計畫第二、三年將進行不同種類山崩滑動材料試驗，包括九份二山、紅菜坪與土場山崩，預期探討不同類型山崩運移特性與機制。 The magnitude vs. long run-out distance of large scale landslides and related mechanisms ABSTRACT Large landslides with long runout distance frequently cause great loss of life and property. Many researchers are interested in the phenomenon of increasing mobility with landslide volume and the related mechanisms. However, the problem related to the mobility of large landslides has not yet been conclusively solved. In Taiwan, there are some famous large, bedding parallel landslides. Among them, Tsao-Ling landslide site is the most important one, where several large slide events were well documented. During Chi-Chi earthquake, the strong motion was recorded by a strong motion station where very close to the Tsao-Ling landslide site. There are survivors clearly described the sliding process. It is unique opportunity to study the mobility and related mechanism of a large, bedding parallel landslide. In this study, a rotary shear low to high velocity frictional testing machine will be utilized to measure the velocity, displacement, and normal stress-dependent frictional coefficient of sliding surface. The represented rock samples will be sampled from Tsao-Ling landslide site. Based on the experiment results, the relationship between the runout distance and the landslide volume of a bedding parallel landslide could be derived. Furthermore, the kinematics of the moving mass could be calculated using a sliding block model with the derived velocity and displacement-dependent friction law. The results could be verified by the direct or indirect evidences. It is anticipated that the friction weakening could account for the long runout distance of a bedding parallel large landslide. The second and third years of this project will focus on the other important landslide sites. Different sliding materials will be tested and the mechanism of mobility of different category of large landslides will be thoroughly studied. 研究期間：9908 ~ 10007
