砂質土壤於不同含水量下的強度特性研究

Strength Feature Study of Sandy Soil in Different Water Content

何柄樺(Ho-Bing Hua)

指導教授 ： 丁原智

國立臺北科技大學/工程學院/資源工程研究所/碩士(2007年)

摘要

砂與黏土為構成礫石層的重要材料，當水(雨水)的滲入之後，就形成砂漿體和黏土漿體。漿體之流動除了與邊坡幾何參數有關外，其本身之流變性亦居重要之關鍵因素。本文採用SR5流變儀來量測黏土漿體和黏土砂漿體流變參數值並初步建立與土樣強度間之關係，可供未來現地土壤邊坡穩定性模擬時，訂定適當的材料參數和強度參數的參考。
本研究旨在探討模型材料在不同的泥砂配比及不同的含水量下剪應力和應變率的關係，並推估其黏滯係數和降伏剪應力。試驗結果顯示隨著含水量的增加，土壤的強度和黏滯度會有減小的趨勢。相同含水量，含黏土的比例越高，降伏剪應力跟黏滯度都會增加。而不同配比的土樣，會有應力越大，應變率越大符合賓漢塑性體模式的行為。在力學方面，除了考量靜力平衡的觀點外，尚需搭配賓漢流變參數（降伏剪應力τB）與莫爾-庫倫力兩種力的結合。最後並利用有限元素分析軟體PLAXIS V.7.2建置模型，模擬砂質土壤邊坡巨觀行為下現地應力分布、大小及位移量的變化情形，藉由探討砂質土壤含水的塑性行為，期望能對土壤邊坡滑動行為及其強度參數有更進一步的了解。

關鍵字

降伏剪應力

並列摘要

Sand and clay are the important ingredients of gravel, when water infiltrate into gravel, the sand and clay will become sand slurry and clay slurry. Beside geometry parameter of slope, the flowing of slurry also relate with rheometer property by itself. In this work, the parameter value of sand slurry and clay slurry are measured by SR5 rheometer and set up the relationship between the parameter of sand slurry and clay slurry and plastic parameter of soil sample. In order to provide proper material parameters and intensity parameters to the stability simulation of soil slope in the future.
The purpose of this study is discussing the shear stress and strain rate relation under different silt allocated proportion and different water content, and the viscosity coefficient and yield shear stress are estimated. The experimental results show that when the content of water increases, the intensity of soil and degree of viscosity will reduce. With the same content of water, while the percentage of clay increases, yield shear stress and viscosity will increase. Shear strain rate also will increase when shear stress become bigger in the different silt allocated proportion which conforms to Bingham model. In mechanics aspect, beside the viewpoint of consideration static balance, still have to match the Bingham parameter (yield stress, τB) and the combination of Mole－Coulomb force. The PLAXIS v7.2 is used to establish model to simulate various conditions of stress distribution, size and displacement for sandy soil slope. Hoping we can understand the relationship between the slip of soil slope and parameters of strength by discussing the plastic behavior of sandy soil.

並列關鍵字

yield shearing stress

參考文獻

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