本文選題：顆粒形狀 + 剪切特性��； 參考：《巖土力學》2017年08期

【摘要】：碎石顆粒的形狀對于集料的整體剪切性能有很大的影響,而現(xiàn)有的研究缺乏對于不規(guī)則塊體顆粒形狀的定量評價指標。利用離散元軟件PFC2D(Particle flow code,2D)研究,提出了不規(guī)則塊體的生成方法,建立了平面雙軸剪切試驗條件,通過對比室內(nèi)試驗結(jié)果完成了對模型的驗證以及細觀參數(shù)的選擇。通過對塊體進行分割后得到的多邊形相鄰頂角的差值進行分析,改進了棱角度指數(shù)的概念,在此基礎(chǔ)上分析了顆粒形狀對于級配不良的碎石集料的力學性質(zhì)的影響,研究結(jié)果表明:棱角度指數(shù)受劃分邊界數(shù)的影響較大,隨著劃分密度的增加,棱角度指數(shù)不斷減小并趨于穩(wěn)定;隨著軸向應(yīng)變的增加,碎石集料的剪應(yīng)力呈現(xiàn)出明顯的非線性增加,曲線的形態(tài)受顆粒形狀影響較大,除球形顆粒外,其他形狀顆粒集料均呈現(xiàn)出應(yīng)變硬化的特性。在棱角度指數(shù)較低時,抗剪強度和內(nèi)摩擦角緩慢增加,而當棱角度較大時,抗剪強度指標則增加較快,可以通過冪函數(shù)進行擬合。
[Abstract]:The shape of gravel particle has a great influence on the overall shear performance of aggregate, but the existing research lacks quantitative evaluation index for the shape of irregular block particle. Based on the study of discrete element software PFC2D(Particle flow code2D, an irregular block generation method is proposed, and the plane biaxial shear test conditions are established. The model verification and the selection of mesoscopic parameters are completed by comparing the results of laboratory tests. By analyzing the difference of adjacent vertex angle of polygon after block segmentation, the concept of angle index is improved, and the influence of particle shape on mechanical properties of broken stone aggregate with poor gradation is analyzed. The results show that the prism exponent is greatly affected by the number of partition boundaries. With the increase of partition density, the angularity index decreases and tends to be stable, and with the increase of axial strain, The shear stress of crushed stone aggregate showed an obvious nonlinear increase, and the shape of the curve was greatly affected by the shape of the particle. Except for the spherical particle, all the other shaped aggregates showed the characteristics of strain hardening. When the angle index is low, the shear strength and the angle of internal friction increase slowly, but when the angle is large, the index of shear strength increases faster, which can be fitted by power function.
【作者單位】： 北京交通大學土木建筑工程學院;中國鐵道科學研究院鐵道建筑研究所;
【基金】：國家自然科學基金(No.41371081,No.51378057)~~
【分類號】：U414

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