砂土剪切特性的荷载与粒径效应研究

发布时间：2018-04-22 16:47

本文选题：砂土 + 剪切特性　；参考：《中国矿业大学学报》2014年02期

【摘要】：采用自行研制的DRS-1型高压直剪试验系统进行了法向压力0.4~12.0MPa条件下3种不同粒组砂的直剪试验.结果表明,砂土的剪切力学特性与剪切体变特性受法向压力与粒径共同影响,称为荷载效应与粒径效应.剪切耗能因子与剪切体变参数Δh′随法向压力的增大呈非线性减小,这一趋势随粒径增大而更加明显.剪切耗能因子随砂土粒径的增大而增大,但在高压条件下可以忽略.剪切体变参数Δh′受粒径影响,在低压与高压下呈现不同的规律.法向压力影响颗粒破碎程度,进而影响砂土剪切耗能方式,即砂土剪切特性的荷载效应机制.粒径效应在不同法向压力下的机制不同:低法向压力下,粒径影响颗粒变位带状区的厚度;高法向压力下,粒径影响砂土颗粒剪切破碎程度.
[Abstract]:The direct shear tests of three kinds of sand with different granulation groups under normal pressure 0.4~12.0MPa conditions were carried out by using the DRS-1 type high pressure direct shear test system developed by ourselves. The results show that the shear mechanical properties and shear body variation characteristics of sand are affected by normal pressure and particle size, which are called load effect and particle size effect. The shear energy dissipation factor and the variable parameter 螖 h'of shear body decrease nonlinear with the increase of normal pressure, and this trend is more obvious with the increase of particle size. The shear energy dissipation factor increases with the increase of sand particle size, but can be neglected under high pressure. The shear body variable parameter 螖 h'is affected by particle size and has different rules under low pressure and high pressure. Normal pressure affects the degree of particle breakage, and then affects the shear energy dissipation mode of sand, that is, the load effect mechanism of the shear characteristics of sand. The mechanism of particle size effect under different normal pressure is different: under low normal pressure, particle size affects the thickness of grain shift zone, and under high normal pressure, particle size affects the degree of shear fracture of sand particles.
【作者单位】：中国矿业大学深部岩土力学与地下工程国家重点实验室;中国矿业大学力学与建筑工程学院;
【基金】：国家自然科学基金项目(50974117) 江苏省普通高校研究生科研创新项目(CXZZ12_0936) 深部岩土力学与地下工程国家重点实验室开放基金项目(SKLGDUEK1109)
【分类号】：TU411

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