植根土壤剪力強度之實驗量測與數值分析

Experimental Measurement and Numerical Analysis on Shearing Strength of Root Soil Composite

陳秀婷(Hsiu-Ting Chen)

指導教授 ： 吳瑞賢

國立中央大學/工學院/土木工程學系/碩士(2006年)

摘要

基於根力模式之研究，植根對土壤剪力強度增量之計算，已呈現明朗而具體化。本文所取土壤試體分為植根及未植根兩類，各試體之大小均為25㎝×25㎝×60㎝，由直剪試驗所得資料經由分析及處理後，可得植物根系在不同位移下與土壤剪力強度增量之關係，另由根之直接拉力及握裹試驗，尋求根之抗拉應力及根與土壤間之握裹應力。研究中將探討植生根系之長度、斷裂強度及彈性係數與根直徑間之關係，並提出各關係式之使用參數。最後將以根系力學理論為基礎，再考慮根之彈性變形、根與土壤間之握裹應力及根之斷裂強度等因素，建立分析模型。經由模擬所得土壤抗剪強度增量之預測值與試驗值比較，顯示分析模型所得預測值與試驗之結果吻合。

關鍵字

剪力強度 ； 荷重位移關係 ； 含根土壤

並列摘要

Based on the formulation of the Soil-Root Strength Models development, the amount of root/soil resistance exceeds soil mass strength has been determined. To measure such reinforcement, direct shear tests were made on 25㎝×25㎝×60㎝for rooted and fallow soil cubes. By means of the experimental data analysis, the variation of root reinforcement with shear displacement could be obtained. On the other hand, the ultimate tensile strength of root and the tangential strength between root and soil were measured by direct pull-out and bonding tests. Relation of Young’s modulus, tensile strength and root length to root diameter was discussed, then the parameters for each species were proposed. The analytical model based on the soil-root mechanical behavior, which respond to the loading by root stretching, root slipping, and root breaking, was established. To make a comparison of the data of shearing strength increment between simulations and experiments, it was observed that the analytical predictions are reasonably coincident with those from the experimental measurement.

並列關鍵字

shear strength ； rooted soil ； load-displacement relation

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