 |
|
|
 |
[ 開啟全部內容 ]
[ 隱藏全部內容 ]
|
| INTRODUCTION TO SOIL NAILING TECHNIQUE |
|
| 陳榮河、何嘉浚 |
|
| 土釘、加勁、穩定分析、監測 |
|
| 土釘擋土工法因具有施工迅速且成本低廉等之優點，故於歐美地區使用普遍；而國內則是近十年來才開始較廣泛的將土釘使用於邊坡穩定及開挖擋土結構。雖然土釘自1970年代發展迄今已逾三十年，相關之研究卻一直到1980年以後才陸續提出，然其現地加勁原理、力學機制及設計方法等，仍有部份未臻明確之處。本文主要目的便是針對土釘現地加勁技術之原理及特性，以及其與類似工法間之異同點進行比較，同時針對相關之設計理念及穩定分析方法、監測計畫等進行廣泛之介紹。 |
|
| Soil nailing reinforcing technique has been popular in western countries, because it has merits of rapid and economic construction. However, Taiwan began to employ this technique to stabilize slopes and excavations only until ten years ago. Though it has been thirty years after the development of soil nailing technique since 1970s, the method still has some area under active research such as mechanism, design method, etc. This article compares the differences in the reinforcing principles among similar reinforcement methods at first. Then, the reinforcing characteristics, designing methods as well as monitoring program are also introduced extensively. |
| |
|
| FAILURE MECHANISM AND SEISMIC RESPONSE OF NAILED STEEP SLOPES |
|
| 洪勇善 |
|
| 邊坡、土釘、力學行為、破壞機制、耐震行為 |
|
| 土釘的應用已由發展之初的作為臨時支撐或輔助工程，逐漸也作為永久支撐結構；因此，完善的設計除了靜態分析外，動態特性也必須加以考量。本文先就近幾年土釘應用於陡坡加勁之力學機制與行為之研究予以彙整，並以此為基礎進行土釘加勁邊坡受振時之反應與耐震特性的探討，以供坡地整治時之參考。 |
|
| Soil nailing has been used successfully in temporary and permanent applications on new and remedial constructions in rural and urban areas. Therefore, the seismic resistance and failure mechanism of nailed slope are worthy of investigation to find a method of stabilizing steep slopes subjecting to seismic strike. Literature on nailed structures emphasizing the mechanical behavior of reinforcement and the interaction mechanism between nail and soil are reviewed. In addition, the seismic response and earthquake resistance of nailed steep slopes are discussed as well. |
| |
|
| INVESTIGATION OF OPTIMUM DESIGN OF SOIL-NAILED RETAINING STRUCTURES |
|
| 范嘉程 |
|
| 土釘，最佳化設計，安全係數，土釘-土壤互動機制，有限元素法 |
|
| 土釘擋土結構或邊坡穩定工程之土釘設計配置多為由坡頂至坡趾採等距、等長度之均勻配置，此種設計配置雖能提供足夠之邊坡穩定作用，惟就土釘材料使用之經濟性與邊坡穩定安全性之需求而言，土釘於邊面上之均勻幾何配置並非為最佳設計。本文就下列各項影響土釘擋土結構或邊坡安全穩定性之因素進行探討，包括：1)土釘之傾斜角度；2)土釘材料之抗彎勁度；3)土釘於邊坡不同高度之配置長度；4)土釘於邊坡面上之配置位置等。本文結合土釘-土壤互動之力學機制及非線性有限元素數值模式為分析架構，探討土釘之配置方式與材料抗彎性質對邊坡穩定貢獻之影響，並以邊坡穩定安全係數為評估依據，本文之研究成果可提供土釘擋土結構最佳化設計之參考。 |
|
| Soil nailing is normally designed with uniform length and equal spacing for the soil nailed walls and slopes. Uniform arrangement of soil nailing on the retaining walls and slopes may meet the requirement of stability. However, it may not be the optimum design in terms of the economic concern. Factors affecting the stabilization of soil nailed structures and slopes are investigated through: (1)inclination of soil nailing; (2)bending stiffness of soil nailing; (3)length of soil nailing at different elevations; (4)location of soil nailing on the outward surface of the walls or slopes. Investigation of mechanical behavior of soil-nail interaction is carried out in this study. Effect of deployment and bending stiffness of soil nailing on the contribution of stabilization of walls and slopes are assessed in terms of factor of safety, analyzed with the nonlinear finite element methodology. Findings of this study are helpful to the optimum design of retaining walls or slopes stabilized with soil nailing. |
| |
|
| TWO-DIMENSIONAL NUMERICAL ANALYSIS OF SOIL NAIL REINFORCED SLOPE |
|
| 李維峰、賴盈如、廖南華 |
|
| 邊坡穩定分析，二維數值分析，極限平衡法，工作應力法，土釘加勁材 |
|
| 台灣地區由於山多平原少，再加上平原區人口密度與交通量也日趨飽和，因此山坡地的開發利用與深基礎開挖等興建計劃也逐年增加。而此類工程個案在設計上最常面臨的問題便是邊坡的穩定分析與整治設計。一般常用於邊坡穩定分析的方法包含極限平衡法（Limit Equilibrium Analysis）及工作應力法（Working Stress Analysis）二大類，隨著電子計算機的發展及進步，各種方法所牽涉到的數值分析，皆可由電腦代勞，然而許多工程師往往忽略最基本的分析方法理論基礎與假設，以及數值分析輸入參數的選用與判釋，以致分析結果產生許多謬誤，因此本文主要目的在於說明分析方法的理論基礎假設，並針對土釘等加勁材提供二維數值分析輸入參數的選用建議，尤以土釘與土壤之間互制行為會影響參數的選用，最後藉由SLOPE/W以及PLAXIS程式對美國一道路邊坡案例與本期相關文章中台灣北部兩處基地開挖邊坡案例進行分析，然因案例無實際量測結果，因此作者以工程實際經驗說明參數的選用建議及結果的判釋。 |
|
| A rapid growing of slope development and deep excavation in Taiwan reflects the need of increasing population and transportation. From the engineering point of views, the challenge to satisfy this need is the slope stability analysis and mitigation design. With the progress in computer techniques, the common engineering practice of slope stability problem is using the Limit Equilibrium Analysis and the Working Stress Analysis. However, engineers usually fail to use the proper fundamental judgment on the theoretical background and parametric definition, which leads to an unavoidable misleading. For this purpose, this article introduces a two-dimensional analytical approach on the design of soil nail and soil reinforcement, especially focusing on the interaction between soil and soil nail. By using SLOPE/W and PLAXIS, this article will also use example sites, such as a slope in U.S.A. and two excavation sites in Northern Taiwan, to demonstrate a proper procedure. This procedure provides a proper method of defining parameter values and interpretation of computational results. |
| |
|
| THE APPLICATION AND CASE STUDIES OF SOIL NAILING FOR SLOPE EXCAVATIONS |
|
| 呂芳熾、林永光、郭晉榮、黃志祥 |
|
| 土釘、現場土壤加勁、噴凝土(噴漿)、動極限分析 |
|
| 本文將以美國聯邦高速公路局(Federal Highway Administration,簡寫為FHWA)所提出土釘加勁工法之“最佳可用設計法”(Best Available Design Method)設計斜坡開挖配合土釘加勁與噴凝土護坡方式，作為地下室開挖之臨時性擋土結構或整地修坡之永久性擋土及護坡結構。文中除簡述“最佳可用設計法”之設計原則及設計方法外，並以此“最佳可用設計法”之實際施工及完工案例說明土釘加勁工法應用於斜坡開挖擋土護坡之情形，希望能提供各位讀者及工程先進參考。惟上述工程案例皆無配置相關觀測儀器，故無法提供實際觀測行為以資參考比較，實屬可惜。 |
|
| Based on FHWA’s Best Available Design Method of Soil Nailing, this article describes the principle of Best Availlable Design Method and presents two design cases for slope and basement excavation. In these cases soil nailing and shotcrete were adopted. In the slope excavation case galvanized steel bars were used as inclusions for permanent slope retaining system. Descriptions of several in-situ works are also presented for reference. It is unfortunate that no instrumentation was installed in presented cases. No comparisons can be made for further study. But it proves FHWA’s Best Available Design Method of Soil Nailing is satisfactory. |
| |
|
| APPLICABILITY OF SOIL NAIL AND CASE STUDY |
|
| 孫介文、姚大鈞 |
|
| 土釘，邊坡穩定，擋土結構 |
|
| 土釘工法最初由法國開始使用，由於工法之便利及經濟性與可作為臨時或永久結構物之特性，其應用範圍與規模有愈來愈廣的趨勢。除常見使用於擋土設施之設計外，於國內公共工程之設計中土釘工法亦有作為邊坡穩定的案例。本文主要簡介土釘作為邊坡穩定工法之優點及其運用之限制，並將以國內某工程為例介紹所使用之設計分析方法，作為工程界進行相關設計時之參考。 |
|
| Soil nails were first designed and installed in field in France. Because of their advantages in construction efficiency, cost, and application in both temporary as well as permanent structures, soil nails have been used for various stabilization purposes and the technology has been significantly advanced since their first application. In addition to the use in earth retaining structures, soil nails have been designed for the slope stabilization in public civil works. This paper presents the advantages of using soil nails for slope stabilization and the application restrictions. An example was used to demonstrate the design methodology |
| |
|
| AN INTRODUCTION FOR OPERATION AND ANALYSIS OF SUSPENSION PS LOGGER |
|
| 陳銘鴻、李榮瑞 |
|
| 懸盪式井測儀，井測，波速量測 |
|
| 為使交通部中央氣象局所設之六百多處自由場強震儀觀測站所量測之地震記錄在分析時可同時考量測站場址之地質特性，國家地震工程研究中心與中央氣象局自民國八十九年起合作對自由場強震儀觀測站之地質狀況進行調查。調查工作中選用懸盪式井測資料擷取系統量測強震儀觀測站地層波速結構。懸盪式井測資料擷取系統本身具有震源與受波器同體的特性，在適當的鑽井作業配合下可以連續、便利且較為準確地量測地層中之波速情形，而其所得資料可利用震源與受波器間之相對位置進行交叉驗證以定出真實波速值。 |
|
| The site geological condition investigating project for more than 600 strong ground motion stations was conducted by National Center for Research on Earthquake Engineering (NCREE) in corporation with Central Weather Bureau (CWB) since 2000, therefore the geological properties could also be considered in strong ground motion records analysis. Suspension PS Logger was used in the investigation to measure stratum velocity profile. For PS Logger, the receivers that detect the wave, and the source that generates the wave, are moving as a unit in the borehole. The elapsed time between arrivals of the waves at the receivers is used to determine the average velocity of a 1-meter-high column of soil around the borehole. Source to receiver analysis is also performed for quality assurance. |
| |
|
| APPRASIAL OF SPT-N METHODS IN LIQUEFACTION ANALYSIS BY USING THE CHI-CHI EARTHQUAKE DATA CASES |
|
| 黃俊鴻、楊志文 |
|
| 液化、簡易法、成功率、安全係數、誤差指標、適用性、集集地震 |
|
| 以現有SPT-N簡易法評估土壤之液化潛能，結果常有顯著之差異。瞭解各方法之適用性，就變成工程界待解決之重要課題。本文以評估方法之判定成功率與至少安全係數誤差指標Fm為評估指標，利用302筆集集地震液化與非液化案例資料評估國內常使用五種液化評估方法的適用性。判定成功率代表一個方法判定液化與否之準確程度，Fm代表誤判時之相對安全係數誤差程度。評估結果顯示以NCEER’97法與Seed’85法之整體判定成功率最高，至少安全係數誤差指標Fm最小，可認為適用性較佳；T-Y’83法及JRA’96法之表現次之，適用性也次之；JRA’90法表現最差，可認為是較不適用之方法。 |
|
| Great discrepancies are often found between the evaluated results, when using various simplified SPT-N methods to evaluate soil liquefaction potential. Therefore, it is important to know which simplified method is more suitable for use. However, this problem is not solved yet. Using a total of 302 liquefied and non-liquefied cases during Chi-Chi earthquake, this paper proposed two assessment indices, prediction success rate and at-least safety factor error, to appraise the suitabilities of the five simplified SPT-N methods currently used in Taiwan. Success rate is an index that represents the accuracy of a method in predicting whether liquefaction occurs or not. On the other hand, at-least safety factor error is an index to indicate the relative error of the calculated safety factor by a method. Based on the appraisal, it is found that among the five methods, the success rates of NCEER’97 and Seed’85 methods are the highest and their at-least safety factor error are also the lowest, thus, these two methods can be considered to be most suitable methods. The performances of T-Y’83 and JRA’96 methods are the second. The JRA’90 method has the worst grade, therefore, it is believed to be an unsuitable method. |
| |
|
|
|
|
|
|
|