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第44期 |
台灣之活動斷層 |
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謝敬義 |
1993/12/01 |
90 |
無庫存
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| RECENT ADVANCES ON ENGINEERING EVALUATION OF ACTIVE FAULT |
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| 李錫堤 |
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| 活斷層研究，在最近十年來已有長足進步，並且也已實際應用在工程規劃及設計當中。本文綜合國內外有關活斷層研究及其在工程應用上的新發展，並提出個人見解。
此方面近年來的進展，主要導因於古地震研究上的一些重大發現及對於斷層分段與特性地震的瞭解等。地震斷層力學研究上的進展亦幫助頗大。在美國、日本及中國大陸上，一些主要的斷層開挖及古地震的研究結果，使我們明暸斷層的某一分段，每隔一相當的時間，有產生一相近規模的地震現象。這種地震稱為該一斷層的特性地震，而兩次地震的間隔時間稱為其重複間隔。在應用上，斷層分段、特性地震、最新活動年代、重複間隔及／或斷層滑移速率資料，可以用來推算一條斷層未來某一時段內的發震機率，以為長期地震預測及防災之用。這些資料亦可用來推算一條斷層的地震規模機率密度函數，以供工程上進一步做地震危害分析之用。 |
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| The past decade has witnessed a great advance in studies of active faults, and the results have been applied to a variety of engineering designs and planning. This overview synthesizes major developments in recent studies of active fault and related applications in engineering projects. Suggestion and recommendations on engineering application and further study are also given by the author.
Major developments mainly stem from advances in paleoseismology, and the recognition of fault segmentation and characteristic earthquakes. The progress in the study of mechanics of earthquake faulting is also helpful. From trenching investigations and paleoseismological studies of some active faults in the United States, Japan and Mainland China, it reveals that fault-slip can in-duce almost the same size of earthquake periodically. Such earthquake is known as characteristic earthquake of a fault segment, and the time between two consecutive earthquakes is called recurrence interval of it. Data on fault segment length, characteristic earthquake, elapsed time, recurrence interval and/or fault slip rate have been used to calculate conditional probability of the occurrence of future earthquake, which is useful for long-term earthquake prediction and harzard mitigation. These date can also be employed to develope an earthquake magnitude probability density function for seismic hazard analysis. |
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| THE SIGNIFICANCE OF FAULT AND CAPABLE FAULT IN SITE SELECTION OF AN ENGINEERING PROJECT |
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| 謝敬義 |
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| 能動斷層的存在在工址選擇之考慮上具有相當重要的意義。地質學上的斷層定義與工程法規上對耐震設計所規範的所謂「構造性斷層」不同，此一認知在核能電廠場址選擇上更形重要。本文主要將闡述能動斷層在工程上的概念以及在引起地質災害中，活斷層在動態力學上之特性，同時並說明在工程應用上活斷層調查的必要性。 |
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| The existence of capable fault is one of the most important consideration for siting an engineering project. The definition of a fault in geology is different from that of“structure fault”which is speafied in the code specified for the aseismic design, particularly for siting a nuclear power plant. This paper briefly describes the concept of the capable fault and the dynamic characteristics in consideration of site selection. The necessity of the investigation of a capable fault is also fully discussed. |
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| A REVIEW OF GEOMORPHOLOGICAL STUDY OF ACTIVE FAULT IN TAIWAN |
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| 石再添、楊貴三、張瑞津 |
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| 本研究依地形學觀點，藉航照判讀、地形計測、野外考察及資料分析，所認定的活斷層計158段，其中三分之一集中於歐亞板塊碰撞的臺東縱谷，餘者則分佈於西部山麓地帶的河階及沖積扇。各區主要斷層各有差異，如桃園臺地、大肚臺地的斷層崖、斷層小崖及背斜，而臺東縱谷及潮州斷層帶則為斷錯河階及斷側丘。由斷層所經地形面的對比，可推知斷層活動的相對時期。舊地形面的變位量大於新地形面者，顯示活斷層活動的累積性。至於活斷層活動的頻率及週期尚待更多的證據加以瞭解。 |
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| 158 segments of active fault have been recognized in this study based on air-photo interpretation, geomorphometry, field excursion and data analysis. One third of them are distributed in Taitung Longitudinal Valley where is the collision belt between Eurasian and Philippine Plates and the rest of them distributed in the river terraces and alluvial fans along the foot hill in the west. The main features of active fault are varied in each area, for instance fault scarpments and antithetic scarps are significant in Taoyuan and Tatu Tableland whereas offset terraces and Kernbuts in Taitung Longitudinal Valley and Chaochou fault zone. By correlating the displaced geomorphic surfaces, the relative age of active fault can be interpretated. The displacements of older geomorphic are greater than that of the younger that may reveal the intermittent movements of active faults and the accumulation of fault activity. However, the frequency and period of active fault are not understood clearly. It needs more evidences to figure out. |
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| CONSIDERATION ON THE ACTIVITY OF THE LONGITUDINAL VALLEY FAULT IN THE COASTAL RANGE |
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| 陳文山 |
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| 花東縱谷斷層與奇美斷層是海岸山脈地區最主要的構造線，且為一活動斷層。奇美斷層將海岸山脈劃分為兩個地塊。基於三角點測量，地震、地形與地質的資料結果，顯示南段海岸山脈的活動型態異於北段地段地區。 |
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| Two of the major tectonic breaks in the Coastal Range are the Longitudinal Valley fault and Chimei fault which are active faults. Based on the triangulation, seismic, geographic and structural results, it is apparent that thesouthern Coastal Range is more active than the north in the Holocene. |
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| AGE-DATING OF FAULTS |
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| 劉聰貴 |
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| 斷層的存在對於工程建設的影響相當大。不僅僅由於受斷層剪切作用過之岩石強度變弱，而且斷層本身的活動亦將對土木結構體與建築物造成嚴重的破壞，所以國內外對重大建設工程規定，須將斷層之位置、範圍、活動性作一詳細調查研究，以儘量減少日後受自然斷層災害的影響。除一般野外與地球物理調查可將斷層之位置及大致範圍描繪出來外，對於其活動性之判斷則主要以定年方法測出其活動時段、或者找出其最後一次活動的時間。
本文之目的在簡介測定斷層活動年代的方法，譬如碳十四定年法、熱螢光定年法及電子自旋共振定年法，以供地工界專家、學者之參考。 |
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| Faults have very much influence on civil engineering constructions: notonly because the strength of rocks are weaken, but also the movement of fault can cause serious damage to the constructions. It is thus necessary for large constructions to detail the location and activity of faults as possible. Beside the field and geophysical survey, the precise ages of fault movements are deterimined mainly by age-dating methods. This short paper aims at briefly introducing the most commonly used methods such as radiocarbon（Carbon-14）, thermoluminenscence（TL）, and electron-spin-resonance（ESR）methods. |
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| CASE STUDY ON SEISMIC EVALUATION IN NORTHERN TAICHUNG AREA |
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| 楊恆偉、陳斗生 |
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| 本文重點在於探討如何就緊臨或通過活動斷層的工址進行地震評估，因此特別以台中北部由西向東分佈的彰化斷層、鐵砧山斷層、屯子腳斷層以及車籠埔斷層等四條活動斷層的區域為研究範圍。考慮各斷層的長度與可能工址的距離，以最大可能地震分析法求得在此範圍內最大加速度約在0.55g～0.66g之間，以或然率分析法得知，在50年之設計年限有10％可能超越（即回歸期為475年）的最大加速度為0.25g～0.3g，對於兩種分析方法所得結果之差異及兩種方法的適用性，本文以實例提出了說明及建議，最後對於較高的設計最大加速度，本文也從結構設計的觀點提出以韌性設計的方法，避免結構物在地震作用下發生全面倒塌的情況，並以案例予以佐證。 |
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| This paper presents the seismic evaluation for a site adjacent to or across some active faults. The area investigated is located north to the Taichung Basin, where is known to have four active faults within the range of 15 km, including Changhwa fault, Tiehchienshan fault, Chelungpu fault, and Tuntzechiao fault. By Considering the rupture length and the distance to the site, the Maximum Credible Earthquake（MCE）approach and the Probabilistic method with proper attenuation formulas were used to estimate the peak acceleration and spectrum of the site. Assuming a 50 years design life and a 10% excedence, the peak acceleration was estimated to be 0.55g to 0.66g by using the MCE approach and 0.25g to 0.3g by using the Probabilistic method. Several typical examples were also given to illustrate the applicabilities and the differences between these two methods. With the high acceleration anticipated for this site, it is suggested to use the ductility design to prevent the total collapse of the structure during strong earthquakes. Also, one real case was cited to demonstrate the ductility behavior of the structure during the earthquake. |
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| LATER MOVEMENTS OF SOFT SOIL LAYERS DUE TO SURCHARGE |
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| 王怡仁 |
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| 含有軟弱土層之地盤，因盛土等外加荷重而發生側向變位的事件，於公路橋樑填方邊坡常可發現。本文於是特別針對盛土荷重引起側向變位之各種判定方法、將側向變位納入考量之分析模式及其工程對策作一概要探討。
由於文中所述方法多屬經驗公式而較缺乏理論根據，因此，進一步地試驗、分析及研究以驗證上述公式的正確性是極其必要的。 |
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| The problem of lateral movements of soft soil layers due to the loading of surcharge are frequently encountered at the fill slopes of highway bridges. These paper summarizes the engineering methods which are commonly used to predict the lateral movements of soft soil layers and the analytical models that can be aplied for analyses. Besides, the counter-measures to treat the problem of lateral movements are also introduced in this paper.
Most of the methods discussed in this paper are mainly based on the auther's engineering experiences. Therefore, further researches using analytical approach and experimental data are recommended for future applications. |
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| THE GEOLOGICAL INVESTIGATION AND ITS APPLICATION OF THE PINGLIN PILOT TUNNEL |
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| 張克平、劉弘祥 |
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| 坪林隧道導坑為坪林主隧道施工前之地質探查隧道，其目的在於探查沿線地質構造及地質弱帶、辦理地工計測及試驗、瞭解TBM對不同岩體之鑽進行為、提前排除主隧道岩體內之地下水及提供主隧道施工期間之輔助通道等。本文將就本工程地質記錄、地工計測及地工試驗之整體流程及內容作扼要簡介，最後並說明將所獲得地質資料應用於推估主坑之成果。
計測工作係利用監測儀器之安裝，作為隧道安全監測或岩盤力學參數評估之用。計測斷面依目的分類分為三型，其中A型斷面係為施工安全監測為主，包括收斂計測及頂拱沈陷計測，B型及C型斷面則除施工安全監測之考量外，並進行導坑沿線代表性岩盤變位計測及岩栓軸力計測等。
地工試驗旨在獲取隧道沿線代表性岩盤力學參數，提供未來主隧道岩體分析與支撐設計之用。試驗種類包含現地試驗：平鈑載試驗、孔內變形試驗及套鑽法應力試驗，室內試驗包含動彈性試驗、單區試驗、三軸試驗、張力試驗等。 |
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| The Pinglin Tunnel of The Taipei-Ilan Expressway Project in Taiwan, which has a length of 12.9cm, will be the longest highway tunnel in Southeast Asia and the third longest one in the world. The construction of the pilot tunnel（φ= 4.8m）, which is located between the two main tunnels（φ=11.6m）, was started in August 1991, 18 months ahead of the scheduled excavation of the two main tunnels. The construction of the pilot tunnel is used to obtain parameters on geological conditions, to pre-treat poor strata and pre-drain groudwater, to experience the TBM in difficult ground and to serve as auxiliary tunnel during and after the construction of the two main tunnels. In this paper, the entrie procedure of geological mapping and rockmass classification whose data are stroaged and processed by the program TUNLOG, geotechnical testing and geotechnical monitoring will be briefly introduced. The geological information is then applied to predict the geological conditions during the excavation of the two main tunnels so that the risk can be minimized. |
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