石門集水區優勢植物土－根系統之三維力學轉換模式

3-D Mechanical Conversion Model for the Soil-Root System of the Predominant Plant in the Shi-Men Watershed

林德貴(Der-Guay Lin) ； 邱倍堅(Bei-Jian Chiou) ； 王勝賢(Sheng-Hsien Wang) ； 林信輝(Shin-Hwei Lin)

《中華水土保持學報》 44卷2期 (2013/06) Pp. 105-120

https://doi.org/10.29417/JCSWC.201306_44(2).0002

摘要

本研究針對台灣坡地植生工程常用植物山黃麻，進行根系形態調查及根系材料試驗，並建構及驗證土－根系統之三維數值模型、數值模擬程序及各項材料參數輸入值之有效性。再利用上述三維數值模型，來進行土－根系統直接剪力試驗之數值模擬，以決定根系在土－根系統中提供之抗剪強度增量ΔSr。最後，可建立ΔSr與地上部植生基徑D，以及地下部根系極限拉拔抗力模擬值Pus等參數間之轉換模式：ΔSr=f(D)以及ΔSr=f(Pus)，並採用ΔSr來評估根系對邊坡穩定性之貢獻度。

關鍵字

土－根系統 ； 三維數值模型 ； 根系之抗剪強度增量 ； 極限拉拔抗力

並列摘要

Firstly, a series of field surveys of root morphology and mechanical tests of root material were carried out on Trema orientalis (L.) Blume (India charcoal trema), a plant species commonly used for slope land vegetation in Taiwan. Subsequently, a three-dimensional (3-D) numerical model of the soil-root system was established to simulate an in-situ pull-out test of the soil-root system. The validities of the 3-D numerical model, simulation procedures and various input material parameters in the model were also verified. Subsequently, a 3-D numerical model identical to the soil-root system used in pull-out test was repeatedly adopted for the simulation of a direct shear test to estimate the shear strength increment of the soil-root system due to root ΔSr. Eventually, a mechanical conversion model was developed to correlate the ΔSr with the basal diameter of plant D and the simulation of ultimate pull-out resistance of root Pus, namely, the relationship function ΔSr=f(D) and ΔSr=f(Pus). In addition, the proposed model can be used to determine the required strength parameters for the stability analysis of vegetated slopes and quantitatively evaluate the contribution of a root system to the stability of a slope.

並列關鍵字

Soil-root system ； 3-D numerical model ； increment of shear strength due to roots ； ultimate pull-out resistance