考虑孔隙率和不均匀系数的土石混合体颗粒流分析

为研究低含石率情况下,由土体主导的土石混合体的力学特性,采用分层欠压和随机生成多边形相结合的建模方法,建立土石混合体颗粒流模型,提出不均匀系数作为衡量土石混合体非均质性的指标。通过室内试验校核了颗粒模型的细观参数,并开展双轴数值模拟试验,研究在低含石率情况下,含石率、土体孔隙率和不均匀系数3个因素对土石混合体力学特性的影响。结果表明:在低含石率情况下,土石混合体的强度受土体孔隙率影响较大,随着土体孔隙率的减小,土石混合体的强度有较大提高;块石的存在破坏了土体的均匀性和连续性,反而在低含石率情况下,随着含石率增大,土石混合体整体强度有微小减小的现象;土石混合体的不均匀系数对体应变影响较大,不均匀系数越大,体应变的膨胀现象越明显。

Particle flow analysis of soil-rock mixture considering porosity and heterogeneity

In order to study the mechanical properties of soil-rock mixtures dominated by the soil under a low rock content, the modeling method combining multi-layer method under compaction and random polygon generating method is adopted to establish the particle flow model of soil-rock mixture, and the inhomogeneous coefficient S is proposed as an index of the heterogeneity of soil-rock mixture. The mesoscopic parameters of the particle model were checked by a laboratory test, and the numerical simulation of the biaxial test was also carried out, for checking the effects of three factors on the mechanical properties of the soil-rock mixtures under the condition of low stone content, including the rock content, the porosity and the inhomogeneous coefficient S. In the case of low stone content, the strength of the soil-rock mixture is greatly influenced by the porosity of the soil. With the decrease of the soil porosity, the strength of the soil-rock mixtures is greatly improved. The existence of block stone destroys the uniformity and continuity of the soil. On the contrary, the overall strength of the soil-rock mixture decreases with the increase of the rock content. The inhomogeneous coefficient S has great influence on bulk strain. The greater the coefficient of heterogeneity is, the more obvious the expansion of volumetric strain is.