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  • 學位論文

中至高剪應變下混合土壤的動態參數

Medium to Large-Strain Dynamic Property of Mixed Soils

指導教授 : 郭安妮

摘要


影響土壤的動態參數的因子有很多,如:試體密度、試體有效應力、過壓密比、 塑性…等。本研究是利用一系列動力三軸儀及剪力波原件試驗資料探討砂及砂和 粉土混合土壤的動態特性。本研究所選用的材料是石英砂及人工磨成的石英粉, 試體的配置依細料料含量的不同可分為以下三種:純砂土、5%石英粉混合土樣、 10%石英粉混合土樣。純砂土的試體配置是以乾土重模為主而混合土壤的配置方法 是使用濕搗法。所有的試驗初始是控制一定的乾密度下進行配置,接著以不同的 有效應力來進行壓密,最後再以不同的剪應變來做剪切。 根據試驗結果可以發現剪力模數會隨著剪應變的增加而降低,不過阻尼比卻 是擁有相反的趨勢,是隨著剪應變增加而下降。這個試驗結果,無論是在純砂土、 5%的混合土讓和10%的混合土壤都有一樣的趨勢。除此之外,試體的有效應力也 對動態參數也會有影響,當我們把有效應從100kPa 提升至300kPa 可以發現,正 規畫剪力摩數曲線會因有效應力的增加也有上升的趨勢,當然,阻尼比依然是相 反的趨勢,隨著應力的上升呈現下降的表現。 對於最大剪力摩數我們也有探討,細粒料的添加對於最大剪力摩數也有影響, 依剪力波原件試驗結果可以發現,細粒料的添加對於最大剪力摩數有降低的趨勢, 當然,試體有效應力上升會使得最大剪力摩數也有上升的表現。 本研究著重點著重於三個主要的影響因子,分別是:有效應力、細粒料含量 還有剪應變大小。探討這些因子對於動態摩數及阻尼比有何影響,詳細的內容皆 在以下的章節做詳細的介紹。

並列摘要


There are many factors affecting the dynamic soil properties, including soil density, confining pressure, over-consolidation ratio, plasticity, mineralogy, and particle shape, etc. This research examined the dynamic behavior of pure sand and sand-silt mixture by a series of strain-controlled cyclic triaxial and bender element tests. Materials used in this study were pure quartz sand and sand with various percentages of quartz silt (5% and 10%). All tests were carried out under the same initial dry density. Effects of initial effective confining stress and strain amplitude are considered. From the test results, shear modulus of the mixed soil decreases as shear strain increases. However, damping ratio increases with increasing shear strain amplitude. This trend is consistent with past research on pure sand or pure clay materials. . In addition, when the initial effective confining stress increases from 100kPa to 300kPa, the mixed soil would have a higher shear modulus and become more linear (i.e. less modulus reduction and less damping). Lastly, increasing fines content would lower the shear modulus and increase the damping ratio.

參考文獻


20. Jafari, M. K., Shafiee, A. and Razmkhah, A. (2002). "Dynamic Properties of
19. Hassanipour, A., Shafiee, A. and Jafari, M.K. (2010). "Low-Amplitude
14. Das, B.M. and Ramana, G.V. (2011) Principles of Soil Dynamics, Cengage
1. Abbiss, C. P. (1981). "Shear wave measurements of the elasticity of the
ground," Geotechnique 31, No. 1, pp. 91-104

被引用紀錄


Kao, Y. H. (2015). 混合土壤動態參數之研究 [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342%2fNTU.2015.01755
Tseng, I. C. (2015). 樁基礎受震行為之數值模擬 [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342%2fNTU.2015.00832

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