山坡地社區落石災害防治研究

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(1)山坡地社區落石災害防治研究. 內政部建築研究所委託研究報告中華民國九十五年十二月.

(2) PG9501-1103 095-301070000G3-201. 山坡地社區落石災害防治研究. 受委託者：財團法人中興工程顧問社研究主持人：顧承宇協同主持人：高憲彰研. 究. 員：翁孟嘉. 研究助理：林金成. 內政部建築研究所委託研究報告中華民國九十五年十二月.

(3) ARCHITECTURE AND BUILDING RESEARCH INSTITUTE MINISTRY OF THE INTERIOR RESEARCH PROJECT REPORT. Study on Rockfall Hazard Mitigation for Hillside Resident Communities. BY KU, CHENG YU KAO, HSIEN CHANG WENG, MENG CHIA LIN, CHIN CHENG. December 15, 2006.

(4) 目次. 目次. 表次························································································································ Ⅲ 圖次························································································································ Ⅴ 摘要························································································································ XI 英文摘要 ··············································································································· XVII 第一章緒. 論 ·····································································································1. 第一節. 前言 ······················································································1. 第二節. 研究方法 ··············································································6. 第三節. 研究內容與流程··································································9. 第二章山坡地落石災害評估準則 ····································································11 第一節. 前言 ······················································································11. 第二節. 山坡地落石災害評估準則 ·················································18. 第三章山坡地社區落石災害分析模式建立 ····················································27 第一節. 落石問題特性 ······································································27. 第二節. 相關研究現況 ······································································34. 第三節. 坡地社區落石分析模式······················································37. 第四章快速地形量測技術建立 ········································································67 第一節. 概述 ······················································································67. 第二節. 地形測量 DEM····································································75. I.

(5) 山坡地社區落石災害防治研究. 第三節. 落石邊坡掃描成果······························································83. 第五章防護方式與工法研究···········································································105 第一節. 落石防治工法之一般性原則 ···········································105. 第二節. 山坡地社區落石防治工法 ···············································111. 第六章山坡地社區落石案例分析 ··································································123 第一節. 落石案例評估 ····································································123. 第二節. 美的世界坡地社區落石案例分析 ···································131. 第三節. 南雅里社區落石案例分析 ···············································145. 第四節. 落石問題對山坡地社區建築物退縮距離之檢討···········155. 第七章結論與建議···························································································159 附錄一三維雷射掃描儀器規格 ········································································163 附錄二現行有關退縮距離之法令 ····································································169 附錄三回彈參數建議表·····················································································173 附錄四第一次專家座談意見·············································································179 附錄五第二次專家座談意見·············································································183 附錄六期中審查意見·························································································189 附錄七期末審查意見·························································································195 參考書目 ···············································································································201. II.

(6) 圖次. 圖次. 圖 1-1 基隆中山二路落石，壓毁 3 棟民宅(1998 年 09 月 04 日) ···············4 圖 1-2 台北縣瑞芳南雅里社區落石(時間不詳)·············································4 圖 1-3 台北市信義區松山路美的世界社區落石(時間不詳) ························5 圖 1-4 石碇落石災害，3 棟民宅，2 部車輛受損(2006 年 06 月 03 日)·····5 圖 1-5 研究流程圖·····························································································10 圖 2-1 簡易現地坡高估計法 ············································································19 圖 3-1 常見三種落石運動型態(Ritchie, 1963)···············································28 圖 3-2 落石崖錐之 (F)與 (M) ·······································································29 圖 3-3 落石之速度分布 ····················································································31 圖 3-4 落石之彈跳高度 ····················································································32 圖 3-5 球度與圓度估計圖 ················································································32 圖 3-6 落石之衝擊力·························································································33 圖 3-7 CRSP 程式分析落石示意圖·································································36 圖 3-8 Ritchie 等人落石防護設施建議···························································36. V.

(7) 山坡地社區落石災害防治研究. 圖 3-9 塊體間之接觸力學示意圖 ····································································37 圖 3-10 回彈係數示意圖 ··················································································39 圖 3-11. Rn 回彈係數試驗結果(Chau, 2002) ··················································41. 圖 3-12. Rt 回彈係數試驗結果(Chau, 2002) ··················································41. 圖 3-13 分離元素法之發展歷程 ······································································46 圖 3-14 DDA 之理論架構示意圖 ····································································50 圖 3-15 DDA 之運算架構·················································································53 圖 3-16 單一塊體於邊坡上之幾何模型··························································59 圖 3-17 DDA 與極限平衡法安全係數計算結果比較····································61 圖 3-18 DDA 於計算至安全係數小於 1 時之塊體發生滑動情形 ···············61 圖 3-19 單一塊體於邊坡上之幾何模型··························································63 圖 3-20 DDA 與極限平衡法安全係數計算結果比較····································65 圖 3-21 DDA 於計算至安全係數小於 1 時之塊體發生滑動情形 ···············65 圖 3-22 DDA 法計算結果與 Ritchie 等人落石試驗之結果比較 ·················66 圖 4-1 數值地形模型之表示方法 ····································································71 圖 4-2 以衛星影像立體對進行 DTM 製作之示意圖 ····································73 圖 4-3 航照影像 DTM (5 m 解析度)······························································74 圖 4-4 衛星影像 DTM (5 m 解析度)······························································74 圖 4-5 雷射掃瞄運作方式 ················································································79 圖 4-6 崩塌地三維雷射掃描位置 ····································································80 VI.

(8) 圖次. 圖 4-7 後方固定孔鑽設(左圖)與固定點反射鏡安裝(右圖)····························81 圖 4-8 高精度 GPS 定位施測 ············································································81 圖 4-9 邊坡三維雷射掃描反射點資料······························································82 圖 4-10 邊坡三維雷射掃描位置空照圖····························································84 圖 4-11 美的世界社區全景···············································································85 圖 4-12 美的世界社區崩塌地三維雷射掃描位置 ·········································85 圖 4-13 美的世界社區高精度 GPS 定位施測················································86 圖 4-14 美的世界社區邊坡三維雷射掃描反射點資料 ·································87 圖 4-15 美的世界社區高解析度數值地形模型··············································88 圖 4-16 落石邊坡之二維地形剖面資料(第一處邊坡) ·································89 圖 4-17 落石邊坡之二維地形剖面資料(第二處邊坡)···································90 圖 4-18 南雅里社區第一處邊坡三維雷射掃描位置空照圖 ·························93 圖 4-19 南雅里社區第二處邊坡三維雷射掃描位置空照圖 ·························93 圖 4-20 第一處邊坡位置現地照片 ··································································94 圖 4-21 第一處邊坡現場施作情形 ··································································95 圖 4-22 GS200 雷射掃描儀(左圖)與 GPS 定位(右圖)··································96 圖 4-23 第一處邊坡現場落石照片 ··································································96 圖 4-24 第一處邊坡現場落石照片(近照) ·······················································96 圖 4-25 第一處邊坡數值地形模型全景··························································97 VII.

(9) 山坡地社區落石災害防治研究. 圖 4-26 第一處邊坡數值地形模型疊合照片影像 ·········································97 圖 4-27 第一處邊坡旁落石原始三維雷射掃描點 ·········································98 圖 4-28 第一處邊坡旁落石原始三維雷射掃描點疊合照片影像·················98 圖 4-29 第二處邊坡位置現地照片 ··································································99 圖 4-30 第二處邊坡原始三維雷射掃描點······················································100 圖 4-31 第二處邊坡數值地形模型 ··································································100 圖 4-32 第一處邊坡落石邊坡之二維地形剖面資料 ·····································101 圖 4-33 第二處邊坡落石邊坡之二維地形剖面資料 ·····································102 圖 5-1 落石防護之工法 ····················································································108 圖 5-2 落石防護工法整體示意圖 ····································································110 圖 5-3 防落石柵於落石防治之現況應用(基隆碧砂漁港) ····························119 圖 5-4 南雅里社區內之防落石柵 ····································································119 圖 5-5 石碇一民房建築物前之防落石柵設置················································120 圖 5-6 防落石柵堆滿落石後之情景 ································································121 圖 6-1 美的世界社區附近山勢地形 ································································132 圖 6-2 美的世界社區落石來源區之弱面調查················································132 圖 6-3 美的世界社區過去落石掉落情形························································133 圖 6-4 美的世界社區社區第一處邊坡落石分析邊坡幾何(近圓形落石)····138 圖 6-5 美的世界社區社區第一處邊坡落石分析結果(近圓形落石) ············138 圖 6-6 美的世界社區社區第一處邊坡落石分析邊坡幾何(近方形落石)····139 VIII.

(10) 圖次. 圖 6-7 美的世界社區社區第一處邊坡落石分析結果(近方形落石) ············139 圖 6-8 美的世界社區社區第二處邊坡落石分析邊坡幾何(近圓形落石)····140 圖 6-9 美的世界社區社區第二處邊坡落石分析結果(近圓形落石) ··········140 圖 6-10 美的世界社區社區第二處邊坡落石分析邊坡幾何(近方形) ········141 圖 6-11 美的世界社區社區第二處邊坡落石分析結果(近方形落石) ········141 圖 6-12 美的世界社區社區第一處邊坡落石分析結果(集塊質量法) ········142 圖 6-13 美的世界社區社區第二處邊坡落石分析結果(集塊質量法) ········142 圖 6-14 美的世界社區社區第一處邊坡落石分析結果(下方防落石柵)······143 圖 6-15 美的世界社區社區第一處邊坡落石分析結果(上方防落石柵)······143 圖 6-16 美的世界社區社區第二處邊坡落石分析結果(下方防落石柵)······144 圖 6-17 美的世界社區社區第二處邊坡落石分析結果(上方防落石柵)······144 圖 6-18 南雅里社區第一處邊坡位置······························································146 圖 6-19 南雅里社區第一處邊坡落石與建築物位置示意圖 ·························146 圖 6-20 南雅里社區第一處邊坡落石分析邊坡幾何 ·····································148 圖 6-21 南雅里社區第一處邊坡落石分析結果(DDA) ··································149 圖 6-22 南雅里社區第一處邊坡落石分析結果(Rocfall) ······························149 圖 6-23 南雅里社區第二處落石分析邊坡幾何(左)與分析結果 ··················150 圖 6-24 南雅里社區第二處邊坡落石分析結果(Rocfall) ······························150 圖 6-25 南雅里社區第一處邊坡落石分析結果··············································152 IX.

(11) 山坡地社區落石災害防治研究. 圖 6-26 南雅里社區第二處落石(近方形)分析邊坡幾何(左)與結果 ···········153 圖 6-27 南雅里社區第一處邊坡落石分析結果(Rocfall) ······························153 圖 6-28 南雅里社區第一處邊坡落石分析結果(考慮防護設施) ··················154 圖 6-29 南雅里社區第二處邊坡落石分析結果(考慮防護設施) ··················154 圖 6-30 Ritchie 等人對於 35 公尺以下之邊坡所提之防護建議··················156 圖 6-31 依據 262 條之二退縮距離之計算結果 ···········································157 圖 6-32 落石簡化分析案例幾何設定······························································158. X.

(12) 摘要. 摘. 要. 關鍵詞：落石、雷射掃描、數值模擬、落石防護一、研究緣起台灣位於歐亞板塊與菲律賓板塊交接處，地處造山運動之板塊邊緣，因此台灣之自然環境特性多為地形陡峻、地質破碎、節理發達，再加上民國 88 年間之 921 大地震後，使得岩坡表面之開裂節理鬆動，在颱風、地震或豪雨過後常發生落石災害。行政院國家科學委員會於 921 大地震後進行全面性勘災調查顯示，針對坡地崩塌類型之統計結果以岩石滑移、岩屑崩滑所發生之次數最多，共計 218 處，佔總普查筆數之 63%。其次為落石、翻轉型破壞，共計 77 處，佔總普查筆數之 23%。由上統計資料可發現，岩坡落石災害對於山坡地區域所造成之影響實不容忽視。因此有必要針對落石災害對山坡地社區之影響及防治方法進行研究，期降低其危害。二、研究方法及過程本計畫針對落石災害對山坡地社區之影響進行研究，首先建立山坡地社區落石災害評估準則，針對現有山坡地社區可能之落石災害風險提出量化之評估標準，之後就現有之落石分析方法及防護技術進行彙整及評估其適用性，最後選擇具有高度落石災害風險之山坡地社區進行落石防護及落石分析方法之案例研究。各研究項目分述如下：一、山坡地社區落石災害評估準則之研擬台灣地區落石災害經常性發生地點甚多，落石災害分布之位置廣泛且不確定，如何避免或是進一步防治這些潛在之落石災害，或提供山坡地社區民眾有效及直接的資訊，以減少災害損失，應是首要之課題。由於國內以往於落石災害之防治管理方面，多以各維護單位的經驗為主要依據，並沒有一套 XI.

(13) 山坡地社區落石災害防治研究. 量化的標準可供依循。故本研究研擬山坡地社區落石災害之評估準則，將影響山坡地落石風險之各種因子予以量化，訂定危險度分級標準。並依照山坡地社區可能發生落石坍方之機率，及對社區居民之危險性，以危險度分級的方式表示。山坡地社區落石災害評估準則建立後，其研究成果可對於現有山坡地社區可能之落石災害風險提出量化之評估標準，本研究針對 2 處山坡地社區進行成果應用。研究成果除供各專業機構結合山坡地社區管委會用以評估其社區內發生落石之可能地點外，亦可事先防範於未然以減低落石之潛在風險，而量化之評估流程亦可作為日後落石防護設施及相關單位進行防治優先順序評定之參考。二、落石分析模式建立本研究計畫先收集國內外有關落石防護及分析方法之研究資料，檢討現有之落石防護與分析技術之方法，之後再建立落石分析模式。目前常見之落石分析方法之相關研究可概分為三種 : 現場試驗法、數學分析法及經驗法。這些方法主要是找出落石之能量及軌跡，或者是量化之落石速度、衝擊能量及彈跳高度，以提供設計者決定落石保護措施之方式。因落石運動之力學機制屬不連續體力學領域中之大變位計算，主要係考慮落石間相互之接觸與碰撞，及與自然邊坡之碰撞等，故分析方法多採如集塊質量法或是分離元素法中之個別元素法或是不連續變形分析法等進行分析。因此本研究結合集塊質量法與不連續變形分析法理論進行落石問題之分析模擬，以提供山坡地社區相關單位評估是否需增設落石防護設施，同時亦可檢核落石防護設施之效果。三、快速地形量測技術建立由於實際落石情形受地表地形之影響甚大，如何準確的將地表地形條件反映在落石分析中是落石分析之關鍵問題。對於特定邊坡之落石分析設計時 XII.

(14) 摘要. 需採用大比例尺之地形圖或是直接進行地面測量獲取地表地形，惟絕大多數現有邊坡均無法獲取其原始地表地形資料，且間隔相當時間之後，由於地表植生或是其他因素，邊坡地形亦可能大幅變化，故本研究採用目前最新發展之三維雷射掃描測距儀進行特定地點之現地測量工作。雷射掃描觀測儀是利用儀器發射的近紅外光，量測對於測定對象的往返時間及發射角度，藉由儀器在已知之三維座標點上，自動測量地形的三維座標點數據並保存於記憶體中，可提供平距、斜距、方位角、俯仰角、坡度與坡度百分比、現地多邊形面積與二維及三維空間任意兩點間之距離測量，可長時間的觀察與周期性的監測地形變化並精密的偵測出地表輕微的移動，可觀測範圍十分的廣泛，是一種非常適合於危險地形或是坡面掃描的高精度系統。本研究利用三維雷射掃描技術進行坡地地形現地測量，針對測量結果加值應用於落石分析之邊坡幾何剖面之製作，並提供高解析度之數值地形模型，之後再整合分析模式進行分析，期真實反應現地之邊坡地形並提昇本研究落石模擬與預測之準確度。四、防護方式與工法研究有關山坡地社區落石防護部分，目前主要可為「預防」、「防護」及「警戒」等三種防護方式。本研究彙總上述現有之落石防護方式與相關工法並檢討上述各落石防護於山坡地社區之適用性，之後再結合落石分析模式探討落石防護工法之效能，以提出合適之落石防護工法。惟在實際應用上，最佳對策方法之選定應視現地之狀況，就其耐久性、維護管理難易度、施工難易度、可信度和經濟性等效果詳加檢討，再決定採用之工法。五、現地驗證及案例分析研究本研究結合上述山坡地社區落石災害分析模式與快速地形量測技術進一步針對山坡地社區進行實地調查與案例分析工作，總計進行二個社區四處落石邊坡之案例分析研究。 XIII.

(15) 山坡地社區落石災害防治研究. 三、重要發現本研究結合目前國內外最新可應用於山坡地社區落石災害問題之理論分析技術與三維雷射地形量測技術，進行坡地社區落石問題之分析與應用，期提昇坡地社區落石災害之防治技術。依據本研究所獲致之成果可歸納結論如下所述。 1.. 山坡地社區落石災害之評估準則. 經由對山坡地社區之實地調查與資料蒐集後，本研究參考針對道路落石坍方之美國傳統方法及國內之相關研究成果，提出適於台灣地區之山坡地社區落石坍方危險度評估準則。本研究所提出之評估準則與一般道路落石災害之主要防治對象有所差異，其主要考量並非行車風險，而應與建築物的退縮距離及人員出入量有關，結果顯示，本研究所建議之評估準則可作為提供山坡地社區落石災害初步評估使用。 2.. 山坡地社區落石災害分析模式建立. 本研究針對國內外有關落石問題之理論分析方法進行廣泛之收集與研究，除檢討現有之落石分析理論外，亦結合分離元素法中之不連續變形分析法理論基礎進一步發展落石分析技術。案例分析結果顯示，本研究所發展之山坡地社區落石災害分析模式除可對於落石行進軌跡與掉落位置進行預測外，亦可考慮落石幾何影響與防護設施之效果，對於山坡地社區內特定邊坡之落石防治與後續工法選擇有相當之助益。 3.. 快速地形量測技術建立. 本研究為改進傳統地形測量方法及現有 DEM 因取樣間距不易詳細描繪落石之自然邊坡形狀之限制，本研究特別結合目前最新發展之三維雷射掃描技術進行落石邊坡快速地形量測技術之建立。成果顯示，本研究所採用兩款不同形式之雷射掃描儀，分別為 Trimble 公司之 GS200 與 Riegl XIV.

(16) 摘要. 公司之 LPM-2K，兩款雷射掃描儀均可於短時間約 2 至 3 小時內獲取極高精度之落石自然邊坡地形，特別是 Trimble 公司之 GS200 所掃描之地形資料精度甚至可分辨邊坡上之岩體弱面，可有效提供後續落石問題分析評估之重要邊坡幾何資訊。 4.. 現地驗證及分析工作. 本研究結合上述山坡地社區落石災害分析模式與快速地形量測技術，進一步針對山坡地社區進行實地調查與案例分析工作，總計進行四處落石邊坡之分析工作，分別位於台北市信義區美的世界社區及台北縣瑞芳南雅里社區。案例分析結果顯示，本研究成果除可供各專業機構結合山坡地社區管委會用以評估其社區內發生落石之可能地點外，亦可事先防範於未然以減低落石之潛在風險，而量化之評估流程亦可提供日後落石問題詳細分析及防護設施設計之參考。四、主要建議事項根據研究發現，本研究針對行政檢查業務委託民間辦理處理的法制化，提出下列具體建議。以下分別從立即可行的建議、及長期性建議加以列舉。 (一)立即可行建議主辦機關：行政院公共工程委員會協辦機關：內政部、經濟部、交通部、及水土保持局 1.. 建議利用本研究所研擬之山坡地社區落石災害評估準則對更多山坡地社區潛在之落石災害進行評估，建立相關資料庫，達到防災減災之目的。. 2.. 建議利用遙測資料建立大尺度範圍之山坡地社區落石災害之潛勢分析，建立相關資料庫，作為後續進行防治優先順序之依據。 XV.

(17) 山坡地社區落石災害防治研究. (二)中長期建議主辦機關：行政院公共工程委員會協辦機關：內政部、經濟部、交通部、及水土保持局 1.. 台灣地區近年來因平地發展飽和，山坡地社區開發之建築行為將無可避免，然而隨踵而來之山坡地社區災害實有必要加以防範，尤其是台灣西部麓山帶地質區，多含所謂之「單面山」，其一面是順向坡，而背面是倒插坡（或稱逆向坡），倒插坡常是一個較陡的斷崖而易發生落石災害。因此，建議未來可利用本研究所研擬之山坡地社區落石災害評估準則對更多山坡地社區進行落石災害潛勢之評估，以提高山坡地社區之安全並減少相關災害損失，達到防災減災之目的。. 2.. 本研究已完成山坡地社區落石災害分析模式之建立，惟目前仍侷限於二維分析，而三維分析為目前國際上研究之趨勢，建議未來可進一步結合 3 維雷射掃描技術辦理三維落石災害分析模式之研究。. 3.. 本研究針對建築物因落石問題所需退縮距離分析成果顯示，現行法規在陡坡情形下，坡度由 80 度趨近 90 度時，其退縮距離趨近於 0，對於有落石潛勢之陡坡之退縮距離明顯不足。本研究成果顯示對於有落石災害風險之陡坡(坡度 73.3 度)而言，若邊坡為 40 公尺高度，而無任何落石防護設施之情形下，建築物安全退縮距離約為 10 至 11 公尺。若邊坡為 80 公尺高度，建築物安全退縮距離約為 14 至 18 公尺。建議未來可對於有落石潛勢邊坡之退縮距離進行廣泛之討論，以訂定更周詳之建築物退縮距離。. XVI.

(18) 摘要. ABSTRACT Keywords: Rockfall, Laser scanning, Numerical modeling, Rockfall protection. Taiwan is an active mountain belt created by the oblique collision between the northern Luzon arc and the Asian continental margin. The inherent complexities of geological natural creates numerous discontinuities through rock masses in this area, which exist in many forms such as fissures, cleavages, beddings, joints, and even faults. Accordingly, rockfall hazards triggered by earthquake activities and heavy rainfalls occur frequently in Taiwan along the past decades. Especially after the 921 earthquake in 1999, considerable damages of rockfall hazards in hillside resident areas and along engineered slopes are increasing dramatically in which the rockfall hazards become a major obstacle for engineers to deal with. Accordingly, the study on rockfall hazard mitigation for hillside resident communities was proposed herein. The aims of the study are (1) to establish a rockfall hazard rating system for hillside resident communities, (2) to develop a numerical model for analyzing rockfall problems, and (3) to verify the developed rockfall model and to evaluate the problems of rockfall hazards. The results obtained are concluded as follows. 1. Establishment of a rockfall hazard rating system for hillside resident communities. 2. Evaluation of the possible risk of the rockfall hazard for hillside resident communities. 3. Development of the rockfall modeling technique 4. Establishment of the 3D laser scanning technique for hillside resident areas. XVII.

(19) 山坡地社區落石災害防治研究. 5. Evaluation of the possible rockfall protection technique. 6. Providing the appropriate information for further modification of the distance between buildings and slope for hillside resident communities.. XVIII.