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| A STUDY ON THE FAILURE AND STABILITY OF DIP SLOPES |
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| 洪如江 |
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| 順向坡、破壞、穩定 |
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在台灣，大多數大規模與中等規模之坍方災難，由順向坡滑動所造成。著名之例包括草嶺大崩山、九份二山大崩山、汐止林肯大郡坍方、國道中山高速路八堵交流道坍方、國道中山高速公路汐止收費站附近北坡坍方、台北市松山之虎山坍方、等等；每一次順向坡滑動都造成數十人之死亡或交通中斷。義大利Vajont水庫邊坡大坍方，Longarone村村民遇難者1909人，為世界上最慘的一次順向坡破壞之災。
台灣的中、大規模順向坡滑動，多發生於麓山帶的砂、頁岩地層中。脆裂之砂岩下接頁岩或泥岩層，常在持續豪雨或強烈地震的侵襲下滑動。
潛在滑動面在坡面或坡趾「露空」，常造成順向坡滑動；但潛在滑動面之「露空」，並非順向坡滑動的必須條件，更非順向坡滑動的充分條件。
許多大規模順向坡滑動，其潛在滑動面，常在滑動之前已經開裂或早已經過多次滑動，故大多數順向坡滑動之分析，只考慮剩餘剪力強度，而且常假設cr=0。
邊坡穩定分析，在確定影響穩定的主要變數之後，應辦理敏感度分析，以明白某一重要變數 (例如水壓、摩擦角) 的單位變化，會引起邊坡穩定安全係數的多大變化。本文以國道中山高速公路汐止收費站附近順向坡滑動為例，加以示範。
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Most medium- to large-scale landslide disasters in Taiwan are due to dip-slope failures in sandstone and shale formations in the foothill region of western and northern Taiwan. The Tsao-Ling landslide, the Juo-Feng-Err-Shan landslide, the the Lincoln Villa landslide, the Pa-Du landslide, the Shi-Tz landslide, and the Mt Tiger landslide, have been the most noted dip-slope failures in Taiwan. Each of the landslides caused loss of tenth of human lives or interruption of transportation. The great destruction and loss of 1909 human lives caused by the Vajont Slide on 9th October 1963, in Longarone of Italy, has been the most disastrous dip-slope failure in the world.
Exposure (or daylighting) of the potential slip-plane is often but not always a necessary condition for the occurrence of dip-slope failures. A failure surface can be hybrid, which is originally made up of pre-existing natural weak plane and intact rock material before being sheared through.
For many large-scale dip-slope failures, their potential slip-plane had opened up or slipped before failure. It is therefore that only residual shear strength is used for most dip-slope stability analysis, and that residual cohesion is taken to be zero.
The Shi-Tz dip-slope failure has been reanalyzed to illustrate that the water pressure in the vertical open joint and on the potential slip-plane is very sensitive to the stability of a dip-slope.
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| RESULT OF DRAINAGE WORKS IN LI-SHAN LANDSLIDE |
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| 詹連昌、 陳毅輝 |
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| 梨山、地滑地、工程處理、地下排水工法 |
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| 梨山地滑區為過去曾發生大規模地盤滑動所形成之地區，其地質主要是由崩積層及破碎板岩所組成，主要地滑區可分成西、東南I、東南II及東北三個區域，每個地滑區並由數個上下相關連之滑動體所構成，滑動體呈角形或馬蹄形，其長寬近百公尺或數百公尺，滑動面深度在地表下30~60公尺內，屬於大面積之深層地盤滑動。由調查與監測結果發現，其上方覆蓋之崩積層及風化板岩層透水性佳，地表水易入滲而使地下水位上升，降低邊坡之穩定性，因此降雨時引起地下水位上升，推測為造成本區地滑災害的主要誘因。目前之整治方式為施以地表排水、橫向集水管、集水井、排水廊道等整治工程。本文針對現況及施工整治成果進行檢討與評估，並配合相關之研究成果來評定使用工程方法的成效。 |
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| In the past, a large-scale land sliding occurred in Li-Shan area. The geology of Li-Shan area is composed of colluvium and fractured slate. Master landslide is divided into west, southeast I, southeast II and northeast areas. Slideland is formed to angular and horseshoe shape, and it is more than one hundred meters in width and length, and 30-60 meter in depth underground. Because the crack of upper slideland is evident and colluvium is permeable, groundwater is the most likely cause for sliding of the upper layer of slope. The slideland movement is closely related to the rainfall and groundwater fluctuation. Infiltration of rain water is percolated from surface and wild crack is concluded as the main factor influence the stability of slideland. Now engineering operation is conducted using surface drainage, horizontal drainage pipes, drainage wells and drainage tunnel. It is estimated for effective and modified method, and proposed to form the criterion of slideland management. |
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| PLANNING AND DESIGN OF DEBRIS-FLOW PREVENTION COUNTERMEASURES |
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| 謝金德 |
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| 土石流、透過性防砂壩 |
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台灣地區土石流危險溪流依據行政院農業委員會水土保持局於民國91年完成之調查，共有1420條之多。民國88年921地震後，中部重建區土石流發生之頻率更高，其規模亦更大，土石流防治工程實為災害防救重要的一環。由於土石流之特性與一般山洪截然不同，其防治工程之規劃設計與一般治山防災工程有顯然之差別。
本文就土石流發生之原因與條件，土石流防治整體規劃原則，各種防治工法如非透過性防砂埧、透過性防砂埧及沈砂池等之設計予以介紹。此外對於過去在土石流危險溪流施設之整治工程受損之原因亦加以分析檢討，以利工程師規劃設計之參考，期能避免類似工程災害之重演。
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According to the investigations performed by Soil and Water Conservation Bureau, Council of Agriculture, Executive Yuan in 2002, there totally 1,420 streams were categorized as potentially hazardous stream of debris-flow. The frequency of debris-flow occurrence increases with large-scale in the restoration area of central part of Taiwan after chichi earthquake in 1999. Consequently, debris-flow hazards and the associated prevention countermeasures have now become a major concern in disastrous remedies. However, due to the distinct characteristics of debris-flow, which is significantly different from the mountain flooding, the planning and design of prevention works against debris-flow need to be carried out with great care.
This paper presents the design of prevention countermeasures such as consolidation-type sabo dam, open-type sabo dam and debris retention basin on the basis of the factors and conditions controlling the occurrence of debris-flow and the principles of overall planning of debris-flow prevention. In addition, the main causes of the damage of structures and facilities used to prevent debris-flow hazards in the past were also analyzed and discussed. It is of great advantage to the engineers to take the case histories and lessons depicted as a reference in their planning and design works without encountering difficulties.
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| THE TECHNICAL TREATMENTS FOR THE MUDSTONE SLOPE STABILIZATION |
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| 李德河、林宏明、楊沂恩 |
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| 泥岩、邊坡穩定、坡地災害 |
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| 我國的泥岩地層主要出露於西南部麓山帶、東部海岸山脈南端及恆春半島等處，而西南部麓山帶，則是泥岩出露面積最廣的地區，涵蓋面積約為一千四百平方公里。泥岩形成於第三紀的末期及第四紀前期，成岩時間較短，強度較低，遇水後易產生回脹、崩解的現象，抵抗外在環境的能力較差，特別是水的影響。因此，在泥岩地區每逢大雨後，小型崩落及泥流等地質災害則是處處可見，長期則形成蝕溝發達、地表裸露的惡地形，此區域隨著各項大型交通建設如第二高速公路、東西向快速道路的興建，在公路沿線產生大量的切削邊坡，由於邊坡保護設施的設置並非完善，因此每逢雨季常見泥流、邊坡侵蝕等土砂災害，對人民安全造成相當的威脅。因此，在泥岩區特有的地質條件下，如何建立適用的邊坡保護工法，乃是相當值得重視的事情，本文中乃就現有泥岩邊坡保護工法之現況及其成效做一探討，並提供作為爾後泥岩邊坡穩定處理之參考。 |
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| The mudstone stratum in Taiwan is mainly exposed in the southwestern foothills, the southern area of Coastal Range at eastern Taiwan, and the Hengchun peninsula. Among them, the most widespread area of exposed mudstone is the southwestern foothill with about 1,400 square kilometers. This mudstone formation is deposited from the late Tertiary to the early Quaternary. Due to the shorter digenetic period, it has some unfavorable properties such as lower strength, swelling and slaking behaviors, lower resistance of weathering, etc. Recently, several important transportation constructions, e.g. the southern part of the 2nd national highway and the east-west high speed highway, were built through these areas and caused extensive excavations of the mudstone slopes. Serious geologic hazards, such as collapses of retaining walls, failures and erosion of slope, mudflow, exposed vegetation slope, were frequently found after a torrential rain. Hence, how to establish a suitable technical treatment to protect the mudstone slopes becomes an important issue in Taiwan. This paper presents an evaluation results of the protecting methods in use for mudstone slopes and discusses the mechanism of some failure slopes. It may be a helpful reference for the technical treatments of mudstone slope stabilization in the future. |
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| STABILITY ANALYSIS OF WASTE SLOPES |
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| 陳榮河、陳國賢 |
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| 垃圾、掩埋場、邊坡、穩定分析 |
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| 垃圾填築邊坡之穩定性為掩埋場規劃設計之重要一環，本文針對垃圾填築邊坡之破壞型式、垃圾及界面強度性質、靜態及動態之穩定分析方法等，做一整理及概要說明。並選取國外兩處發生破壞之垃圾掩埋場，進行穩定分析，以說明垃圾填築邊坡穩定分析相關參數之選取，並探討垃圾邊坡穩定之影響因素。希望藉由本文對垃圾填築邊坡穩定分析之觀念性的介紹，能提供掩埋場設計、掩埋操作及封閉後等各階段之邊坡穩定分析等參考。 |
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| The stability analysis of waste slopes is very important in landfill plan and design. This paper introduces some subjects for waste slopes including failure types, strength properties, methods of stability analysis, and special considerations. Additionally, in order to show how to choose related parameters in stability analysis, two cases of failure landfill sites are analyzed. Some influence factors on waste-landfills stability are discussed as well. It is hoped that this content will aid the stability analysis of waste slope during all stages of design, operation and closure of landfill sites. |
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| HILL SLOPE STABILITY METHODS AND NATURAL RESOURCES CONSERVATION |
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| 吳輝龍、鄒宗儒、張承愈 |
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| 邊坡穩定、自然保育、自然生態工法 |
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傳統邊坡穩定工程－混凝土構造物，其表面平滑，生物很難附著存活，對環境保育衝擊甚大，故以自然生態工法創造優質環境，遂為當前重要課題。邊坡自然生態工法須因地制宜，依山坡地土砂災害發生類型及環境特性，採行最適當之對應治理機制。
自然生態工法規劃設計採行之五化原則：表面孔隙化、高壩低矮化、坡度緩坡化、材質自然化、界面透水化，能達到防災安全、生態保育、休閒遊憩三合一功能目標，以提高治理之附加價值與經濟效益。本文亦探討土石流及崩塌地源頭處理、河溪治理及特殊地質(紅土台地及泥岩)邊坡穩定採自然生態工法之做法及原則。
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Conventional slope engineering is made up in form of concrete structures in which the quite smooth surface will result in the difficult living condition for other live form. To avoid the impact of traditional concrete slope engineering on the environmental care, the ecological engineering method presents promising meaning.
To achieve the multiple goals of the ecological conservation, safety precaution and recreation center, five fundamental principles, such as small openings of surface, lowing the higher dam, decreasing the angle of slope, adopting natural material and permeable interface, shall be taken into account in planning and design to raise the additional value and economic benefits. Also, this paper describes the ecological engineering method in the treatments of debris flow, the source of slumps and the slope stability in lateritic terrace and mud stone.
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| GEOLOGICAL INVESTIGATIONS FOR DIFFERENT SLOPE STABILIZATION METHODS |
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| 林俊良、何泰源 |
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| 邊坡穩定、地質調查 |
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台灣地區位處歐亞板塊與菲律賓海板塊交界處，坡地面積佔70％以上，加上地形陡峭、地質年代輕、地質構造複雜、岩性脆弱、降雨量多，以及人為開發不當等因素，經常造成各類型坡地災害。
邊坡穩定工法常繫於對工址基地及周邊環境基本資料的瞭解，其中以地質因素最為重要。本文將就邊坡穩定工法所需之地質調查原則及方法加以介紹，期能對於工法的選擇、設計、施工及維護管理有所助益。
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Taiwan is located at the convergent boundary of Euroasian plate and the Philippine Sea plate. 70% of Taiwan area is mountainous. Various hazards are mainly caused by steep topography, complicated folding and faulting geology, heavy rainfalls and inappropriate development of slope.
The feasibility of slope protection measures should consider inherent factors of site, especially geological factors and surrounding environments. It is expected that the geological investigation principles and methods described in this paper would be helpful for engineers in gaining the ability of protection method selection, design, construction and maintenance.
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| STUDY ON SLOPE STABILIZATION METHODS SELECTION |
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| 廖洪鈞、游行健、郭瑞柏 |
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| 邊坡、崩塌機率、正典鑑別分析、邊坡擋土工法 |
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| 本文藉由蒐集道路和社區邊坡已破壞與未破壞案例，配合鑑別分析法和統計套裝軟體-SPSS，建立邊坡崩塌機率之鑑別函數和邊坡擋土工法選定的機制。利用邊坡穩定影響因素之評估準則表，將影響邊坡穩定之子因素量化，進行鑑別分析，得到具顯著鑑別力之各項子因素，包括岩盤層態、地面排水狀況、挖填方情形、坡趾開挖、坡面風化程度和邊坡維護等，將這些具顯著鑑別力之子因素與不同邊坡擋土工法進行鑑別分析，建立不同邊坡擋土工法之鑑別函數，透過這些鑑別函數，求取邊坡擋土工法之崩塌機率及正典鑑別空間中各類擋土工法的落點位置。藉此可協助工程師從邊坡地質條件、坡面排水條件、和人為因素等，初步選定適用於該邊坡之擋土工法。 |
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| Based on the failed and not failed slope cases collected from the public roads or the residential communities, this study will propose a method to select adequate slope stabilization method for specific slope in terms of failure probabilities. This method is established by integrating the canonical discriminant analysis, statistic software SPSS, and slope cases from the field. The influencing factors on the stability of slope are quantified using an evaluation table and substituted to the SPSS analysis. Totally, six factors with significant discriminating ability were identified, namely the structure of bedrock, surface drainage condition, slope cutting, toe excavation, weathering of slope surface, and slope maintenance. These factors are used to establish the discriminant functions for various slope stabilization methods. Using these discriminant functions, the failure probability of a slope protected by certain slope stabilization method can be estimated. In addition, the optimum slope stabilization method can also be selected based on the position of calculated result in the discriminant coordinates. This method can provide a useful means to guide the engineers chossing a suitable slope stabilization method according to the geological condition, drainage condition, and human activity factor of a particular slope. |
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| CONSTRUCTION MANAGEMENT AND HAZARD PREVENTION OF SLOPE STABILITY WITH EPS LIGHTWEIGHT MATERIAL |
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| 林利國 |
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| EPS、輕質填土工法、邊坡穩定、防災工程、施工管理、發泡級聚苯乙烯 |
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| 台灣由於多山多雨的天然條件，以及交通運輸或人口居住的生存需要，使得傍著山坡建築的構造物幾乎是隨處可見；然而，在此等山坡地之邊坡處，卻常常會因為受到地震或降雨的天然因素，或者是由於不當開發或設計錯誤之人為因素，導致邊坡滑動的不幸事故發生；而更令人遺憾的是，此等災害不僅會帶來財物的損失，更會造成人民寶貴生命的傷亡。EPS乃係學名為發泡級聚苯乙烯（Expandable Polystyrene；簡稱為EPS）之塊狀化學合成材料，此等EPS成型產品由於重量輕、具吸震性及易施工等特性，因此極適合應用於台灣地層滑動之之防災需求上。本文針對國內、外有關邊坡穩定及EPS相關資訊進行彙整與介紹，並探討EPS在邊坡穩定之防災應用與施工管理，期望透過本文之說明，可促進EPS材料在國內之防災工程應用與發展。 |
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| There are lots of potential hazardous landslide areas in Taiwan due to mountainous terrain and high-density land-use. Such situation is causing serious problem of unstable construction buildings that are built beside land-slope region. Therefore, landslide disasters claim hundreds of lives and cause millions of dollars of property damage throughout island-wide in each year. EPS is the abbreviation of Expandable Polystyrene. A block of EPS is made from the particle of Polystyrene with expanded and melted process in a specific mold by adding steam gas. The EPS light-weight construction method refers to employ large EPS blocks with unit weight between 12kgf/m3 and 30 kgf/m3 in civil engineering, architecture engineering, disaster prevention and garden engineering. This paper introd relative information of EPS and describes the investigation of EPS production and practice application projects of slop stability. The purpose of this paper’s presentation is trying to motivate more and more people involved to the research and development (R&D) domain of EPS construction method in Taiwan. |
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| STUDY ON DEVELOPMENT AND SUITABILITY OF ANCHORS FOR STABILIZING SLOPES IN TAIWAN |
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| 廖瑞堂、陳昭維、楊品錚 |
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| 邊坡穩定、永久性地錨、防蝕、適用性 |
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| 地錨使用在高挖方邊坡及具有較深層破壞潛能邊坡之穩定功能與防制效益上，確實有其優越性，過去曾廣為國內工程界肯定及採用，但於普遍採用後之地錨，因頗多業者欠缺正確的認知，對其設計與施工品質未能有效確實管控，以至於自從民國86年汐止林肯大郡之順向坡坍塌及地錨嚴重破壞，導致慘重人命傷亡之災變發生後，社會大眾及工程界出現不少反對採用地錨之聲浪。本文主要係對地錨之適用性及設計和施工中，可能存在之諸多缺失逐一探討，並從制度及管理等各方面，提出如何改正錯誤觀念、積習及防止類似地錨破壞災害之建議。希望工程師能以較持平的心態，更審慎的態度，確切瞭解地錨之特性，善用地錨之優點，並嚴控其設計與施工之品質，以防止破壞情事與災害的再度發生；而非受不良案例導引，因噎廢食，將功能及效益皆甚佳，且設計與施工之準則、規範已頗嚴謹、完善之地錨視為畏途，反而應更積極謀求改善地錨品質之道，方為促使邊坡穩定工程技術水準向上提昇，並得以獲致有效防止邊坡破壞與災害之正確思維。 |
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| Anchors are often used as part of the stabilization measure for cut slopes which are high or natural slopes which have high potential of sliding. In the past, this method is used and recognized widely by Taiwan engineering fields. However, due to lack of right understanding, the design and quality of popularly used ground anchors are not controlled effectively. Since the Lincon Community disaster that led to 28 persons died occurred in 1997, many people and some engineers have claimed against using anchors to stabilize slopes. To counter balance the view points, this paper discusses the suitability of anchors, and the key problems encountered during design and construction stages. In addition, some suggestions from system and management aspects are given to correct the wrong concepts and prevent ground anchor failure. And, wish engineers could have open mind and careful attitude to understand the suitability of ground anchor. Utilizing the strong point of ground anchor and well-controlled design and quality to prevent the failure. Don’t give up this kind of well-developed method. On the contrary, engineers should look for better solution to improve ground anchor more aggressively. Then, to promote the technology in slope stability and to acquire appropriate thoughts in avoiding slope failure and calamity. |
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