Study of Mechanical Behavior on Ground Improvement with Deep Mixing Pile

由於黏土層加載完成壓密較一般土壤所需時間較長時 為， 能加速黏土層的壓密速率 攪拌樁是一種較為經濟且快速之地， 盤改良方法，而對於複雜地質內之攪拌樁，理論與設計上仍有 諸多未臻完善之處。近年由於電腦應用程式普及，數值分析方 法已成為設計的參考依據。 本研究針對軟弱黏土以攪拌樁進行地盤改良為案例 利用， 有限元素軟體 Plaxis 2D 程式進行研究，分析未改良與攪拌樁 改良後之軟弱黏土之沉陷行為 並探討相關力學行為與影響因， 子之效應，由研究結果得知：(1)深層攪拌樁工法具有加速黏 土層之壓密及低差異沉陷量之成效，(2)提高攪拌樁面積改良 率可有效降低最終沉陷量及加速壓密之成效，(3)提高樁體彈 性模數可有效降低樁體最終沉陷量 加速壓密完成以及減少差、 異沉陷量，(4)增加樁體垂直方向之排水性能有加速壓密時間 之成效，但並不影響樁體最終沉陷量。Long time is required for clay layers under load compared with other soils. Deep mixing pile is a comparatively economic and fast method of ground improvement in order to speed the consolidation rate of clay. However, there seems some shortage of deep mixing pile with complicated geology in the theoretical and designed aspects. Recently, the numerical analytical method is used as the references of design with the availability of computer applied program. This study is aimed at the settlement, relevant mechanical behavior and the effect of influencing factors of soft clay without and with deep mixing pile as engineering projects using Plaxis 2D program. From the analyzed results, it indicates that (1). Deep mixing pile has the effect of speeding consolidation rate and reducing the differential settlement. (2).The final settlement is reduced and consolidation rate is speeded with the increase in the area of ground improvement. (3).The final settlement of pile can be effectively reduced, consolidation rate is speeded and differential settlement is decrease with higher modulus of pile. (4).The consolidation rate can be speeded with the increase of pile drainage. But there is no effect in the final settlement.目錄 .......................... III 圖目錄........................................ V 表目錄..................................... VII 第一章 緒論 ................. 1 1.1 前言 .......................... 1 1.2 研究動機與目的 ............................. 2 1.3 研究方法 ............................... 2 1.4 內容安排 ............................................. 3 第二章 文獻回顧 ...................................... 4 2.1 深層攪拌工法(DEEP MIXING METHOD) ................................ 4 2.2 攪拌樁數值分析相關研究 ........................ 5 2.3 有限元素方法 ........................... 15 第三章 分析方法 .............................. 18 3.1 PLAXIS 程式 ............................... 18 3.2 模型建立 .................................. 19 3.3 邊界設定 ................................ 20 3.4 材料參數 ........................... 20 3.4.1 線彈性模型 ............... 20 3.4.2 線彈性模型之基本參數 ............................................. 21 3.4.3 修正劍橋模型 ................. 23 3.4.1 修正劍橋模型之基本參數 ......................................... 25 第四章 案例分析 ......................... 27 4.1 前言 ....................................... 27 4.2 研究案例一 ............................... 30 4.3 研究案例二 ..................................... 43 4.3.1 改良前後模型沉陷檢討 ....................... 51 4.4 研究案例三 ...................................... 53 4.4.1 面積改良率 Ir................................. 53 4.4.2 攪拌樁彈性係數 Ecol ......................... 56 4.4.3 土堤彈性係數 Eemb ........................ 58 4.4.4 攪拌樁垂直滲透係數 Kv,col ........................................ 61 第五章 結論與建議 ..................... 63 5.1 結論 ................ 63 5.2 建議 ............... 64 參考文獻.................... 6