Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/55891
標題: 石門集水區優勢植物土根系統三維力學轉換模式之發展
Development of 3-D Mechanical Transform Model for the Soil/Root System of Predominant Plants in Shi-Men Watershed
作者: 林德貴
關鍵字: 土木水利工程類;應用研究;3-D numerical model;三維數值模型;力學轉換模式;抗剪強度增量;mechanical transform model;shear strength increment
摘要: 
本研究將延續2009 年研究計畫(石門集水區優勢植物根系形態調查及其拉拔抗力與抗剪強度之力學轉換模式建置,2009/08/01~2010/07/31)之完成成果,發展土~根系統之三維力學轉換模式。目前在2009 年之前期計畫中,已採用二維數值模型進行植物土~根系統極限拉拔抗力Pu 與抗剪強度增量ΔSr 之力學關係式推導及驗證。由於二維數值模型具有分析簡單、迅速之特點,在實務運用上有其優勢。然而,利用二維數值模型來模擬土~根系統之力學行為仍然需要進行必要的力學轉換,例如:根系材料勁度、根系密度等特性並無法在二維數值模型中作真實呈現。因此,在未來研究計畫中將在既有的室內及現地試驗成果基礎下,採用三維數值工具進行土~根系統之各項力學分析,以提升2009 年二維數值模型研究成果之精準度及可信度。本研究將建構含根土之三維數值模型,並參照現地拉拔試驗之加載方式(採用拉拔力加載控制方式),進行根系現地拉拔抗力試驗之數值模擬。根據模擬結果,分析其拉拔歷程並比對拉拔抗力-拉拔量關係曲線之量測值與模擬值之吻合度。隨之,再採用與根系拉拔抗力試驗數值模擬相同之三維數值模型,進行含根土之直接剪力試驗數值模擬,並推估含根土根系抗剪強度增量值ΔSr。分析上述模擬之數值解,即可建置石門集水區優勢植物根系之極限拉拔抗力Pu與土~根系統抗剪強度增量ΔSr之通用力學轉換模式,即ΔSr=f(Pu)關係函數。最後,再將此根系力學轉換模式結果,運用於植生邊坡三維穩定性分析中,並評估不同植物根系對邊坡土層之加勁效果。

The present work will be the extension of the study of year 2009 entitled “Investigationsof Root Morphology of Predominant Plants in Shi-Men Watershed and Their MechanicalTransform Model from Pull-out Resistance to Shear Strength Increment”. Based on the worksachieved in 2009, this study attempts to develop a generalized three-dimensional (3-D)mechanical transform model of soil/root system.Currently, in the study of 2009, a two-dimensional (2-D) numerical model has beendeveloped to formulate and verify the mechanical relationship of the ultimate pull-outresistance Pu and the shear strength increment ΔSr of soil/root system. Due to the simplicityand the high computation efficiency, the 2-D numerical model is advantageous to the practicalapplications. However, some mechanical conversions and simplifications, such as the stiffnessand the density of the root system, were required and necessary when implementing the 2-Dnumerical simulation. Accordingly, this study is aimed to promote the accuracy and thereliability of the 2-D numerical model by 3-D numerical tools under the basis of thecompleted laboratory and in-situ tests in 2009.Using the 3-D numerical model of soil/root system, the numerical simulations of pull-outtest of the plant root can be performed according to the pull-out force applied in the field site.The 3-D numerical model can be verified by comparing the simulations with themeasurements of in-situ pull-out tests. Further, the influence of the root morphology ofvarious plant species on the pull-out resistance will be examined through a more realisticnumerical modeling technique. Subsequently, the 3-D numerical model of soil/root systemidentical with the pull-out test is repeatedly used for the simulation of direct shear test toestimate the shear strength increment, ΔSr, contributed by the plant root in soil/root system. Ageneralized equation of mechanical transform model, ΔSr=f (Pu), for the aforementionedpredominant plants in Shi-Men watershed can be formulated and used to transform theultimate pull-out resistance Pu into the shear strength increment ΔSr of soil/root system.Eventually, the mechanical transform model will be immediately applied to 3-D slope stabilityanalyses to evaluate the reinforcement effect of various plant roots on the slope of watershed.
URI: http://hdl.handle.net/11455/55891
其他識別: NSC99-2221-E005-046
Appears in Collections:水土保持學系

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