改良粗粒土填料大型三軸試驗(yàn)
本文關(guān)鍵詞: 填料 復(fù)合礫 級(jí)配改良 大型三軸實(shí)驗(yàn) Duncan-Chang模型 出處:《中南大學(xué)學(xué)報(bào)(自然科學(xué)版)》2015年02期 論文類型:期刊論文
【摘要】:為了解路基填料級(jí)配改良后的物理力學(xué)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(jí)配的改良填料,采用大型三軸剪切儀對(duì)素土和復(fù)合礫進(jìn)行三軸剪切試驗(yàn)。在試驗(yàn)基礎(chǔ)上提出軸向應(yīng)變與側(cè)向應(yīng)變的二次函數(shù)關(guān)系,建立體積應(yīng)變與軸向應(yīng)變的函數(shù)方程,并對(duì)試樣三軸試驗(yàn)的體積應(yīng)變和切線泊松比進(jìn)行預(yù)測(cè)。研究結(jié)果表明:粗顆粒質(zhì)量分?jǐn)?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?jǐn)?shù)升高,試樣體變由剪縮趨勢(shì)逐漸轉(zhuǎn)為剪脹趨勢(shì);應(yīng)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?jǐn)?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(yù)測(cè)結(jié)果表明改進(jìn)模型能較合理地描述粗顆粒土填料的體積應(yīng)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(xué)土木工程學(xué)院;中南大學(xué)高速鐵路建造技術(shù)國家實(shí)驗(yàn)室;
【基金】:國家自然科學(xué)基金資助項(xiàng)目(51378514) 高速鐵路建造技術(shù)國家工程實(shí)驗(yàn)室基金資助項(xiàng)目(2008G031-Q)~~
【分類號(hào)】:TU411
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