本文關鍵詞： 填料 復合礫 級配改良 大型三軸實驗 Duncan-Chang模型　出處：《中南大學學報(自然科學版)》2015年02期 　論文類型：期刊論文

【摘要】：為了解路基填料級配改良后的物理力學特性,向素土中摻加3種粒徑范圍內(nèi)不同質(zhì)量比的碎石,制成4種具有不同顆粒級配的改良填料,采用大型三軸剪切儀對素土和復合礫進行三軸剪切試驗。在試驗基礎上提出軸向應變與側向應變的二次函數(shù)關系,建立體積應變與軸向應變的函數(shù)方程,并對試樣三軸試驗的體積應變和切線泊松比進行預測。研究結果表明:粗顆粒質(zhì)量分數(shù)較高的試料在低圍壓下出現(xiàn)剪脹現(xiàn)象,在高圍壓下出現(xiàn)剪縮現(xiàn)象;在低圍壓下,隨著粗顆粒質(zhì)量分數(shù)升高,試樣體變由剪縮趨勢逐漸轉為剪脹趨勢;應用鄧肯-張模型并求得其參數(shù),得出試樣的黏聚力c、內(nèi)摩擦角φ及切線彈性模量Et隨粗顆粒質(zhì)量分數(shù)的增加而增大;鄧肯-張模型不能很好地反映粗粒土填料的變形特性;預測結果表明改進模型能較合理地描述粗顆粒土填料的體積應變特性。
[Abstract]:In order to understand the physical and mechanical properties of the improved subgrade filler gradation, four kinds of improved fillers with different particle gradation were prepared by adding three kinds of gravel with different mass ratios in the particle size range to the plain soil. The triaxial shear tests of plain soil and composite gravel were carried out by using a large triaxial shear apparatus. On the basis of the tests, the quadratic function of axial strain and lateral strain was put forward, and the function equation of volume strain and axial strain was established. The volume strain and tangent Poisson's ratio of triaxial test are predicted. The results show that the specimen with higher coarse particle mass fraction has shear dilatation at low confining pressure, shearing shrinkage at high confining pressure, and shearing shrinkage at low confining pressure. With the increase of coarse particle mass fraction, the shear shrinkage trend of the sample is gradually changed to the shear expansion trend, and the Duncan-Chang model is applied and its parameters are obtained. The results show that the cohesive force c, the angle of internal friction 蠁 and the tangent elastic modulus E _ t increase with the increase of coarse particle mass fraction, but the Duncan-Chang model can not well reflect the deformation characteristics of coarse grained soil filler. The prediction results show that the improved model can reasonably describe the volumetric strain characteristics of coarse grained soil fillers.
【作者單位】： 中南大學土木工程學院;中南大學高速鐵路建造技術國家實驗室;
【基金】：國家自然科學基金資助項目(51378514) 高速鐵路建造技術國家工程實驗室基金資助項目(2008G031-Q)~~
【分類號】：TU411

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