玄武岩纤维灰土力学特性及扩宽路堤边坡稳定性分析

Mechanical properties of basalt fiber ash soil and stability analysis of widened embankment slope

为了探明玄武岩纤维与石灰改良黄土的力学特性及作为扩宽路堤填料时的稳定状态,通过正交设计,进行固结不排水三轴(CU)试验,得到含水率、压实度、纤维掺量、纤维长度等4因素下的最优水平组合,在此基础上,通过控制纤维长度、含水率和压实度不变,将4种不同掺量(0.2%、0.4%、0.6%、0.8%)的6 mm长度玄武岩纤维和石灰复合掺入黄土中,对纤维掺量、纤维长度及龄期对加筋效果的影响进行分析;其次,根据室内试验数据,基于有限元基本原理对纤维灰土扩宽路堤的稳定性进行数值模拟.结果表明:纤维加筋灰土能够显著提高黄土的抗剪强度指标,且黏聚力随纤维掺量增加先增大后减小,0.6%时为最优;7 d龄期纤维灰土黏聚力较3 d龄期有明显提高;安全系数与填土材料关系特征明显,安全系数随纤维掺量先增加后减小;安全系数随扩宽路堤的扩宽宽度和坡度系数增加均呈近似线性增长,随路堤高度增加呈近似线性减小特征.

In order to explore the mechanical properties of basalt fiber and lime improved loess and its stable state as embankment filler,the consolidated undrained triaxial(CU)test was carried out through orthogonal design,and the optimal horizontal combination of four factors,such as moisture content,compactness,fiber content and fiber length,was obtained.On this basis,by controlling the fiber length,moisture content and compactness unchanged,the optimal horizontal combination of four factors was obtained.Six kinds of 6 mm basalt fiber and lime with different content(0.2%,0.4%,0.6%,0.8%)are mixed into loess,and the influence of fiber content,fiber length and age on reinforcement effect is analyzed.Secondly,according to the indoor test data,based on the basic principle of finite element,the stability of fiber reinforced lime soil widening embankment is numerically simulated.The results show that:fiber reinforced lime soil can significantly improve the shear strength index of loess,and the cohesion first increases and then decreases with the increase of fiber content,and 0.6%is the best.Results show that the cohesion of fiber lime soil at 7 d age is significantly higher than that at 3 d age.The relationship also between safety factor and filling material is obvious,and the safety factor increases first and then decreases also with the increase of fiber content.The safety factor increases linearly with the increase of widening width and slope coefficient,and decreases linearly with the increase of embankment height.