西安建筑科技大学学报(自然科学版)

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.

引言
1 试验材料
2 试验内容
3 试验结果与分析
4 试验结果与分析
5 扩宽路堤边坡稳定性分析
6 数值模拟算例结果及分析
7 结论

图1 黄土的颗粒分析曲线<br/>Fig.1 Particle analysis curve of loess

图1 黄土的颗粒分析曲线
Fig.1 Particle analysis curve of loess

图2 玄武岩纤维(6 mm)<br/>Fig.2 Basalt fiber/6 mm

图2 玄武岩纤维(6 mm)
Fig.2 Basalt fiber/6 mm

表1 玄武岩纤维物理力学参数<br/>Tab.1 Basalt fiber physical and mechanical parameters

表1 玄武岩纤维物理力学参数
Tab.1 Basalt fiber physical and mechanical parameters

表2 石灰化学成分<br/>Tab.2 Chemical composition of lime

表2 石灰化学成分
Tab.2 Chemical composition of lime

表3 正交试验的因素水平表<br/>Tab.3 Factor level table for orthogonal test

表3 正交试验的因素水平表
Tab.3 Factor level table for orthogonal test

表4 正交试验结果<br/>Tab.4 Orthogonal test results

表4 正交试验结果
Tab.4 Orthogonal test results

表5 纤维灰土抗剪强度的极差、方差及影响分析表<br/>Tab.5 Analysis of the extreme difference, variance and influence of shear strength of fiber ash soil

表5 纤维灰土抗剪强度的极差、方差及影响分析表
Tab.5 Analysis of the extreme difference, variance and influence of shear strength of fiber ash soil

图3 不同龄期抗剪强度指标随纤维掺量变化<br/>Fig.3 Shear strength indexes at different ages varying with fiber content

图3 不同龄期抗剪强度指标随纤维掺量变化
Fig.3 Shear strength indexes at different ages varying with fiber content

图4 有限元计算模型/m<br/>Fig.4 Finite element calculation model/m

图4 有限元计算模型/m
Fig.4 Finite element calculation model/m

表6 水平因子
Tab.6 Level factor

表7 土的物理力学性质指标<br/>Tab.7 Physical and mechanical properties of soil

表7 土的物理力学性质指标
Tab.7 Physical and mechanical properties of soil

表8 新路堤填土相关计算力学参数表<br/>Tab.8 New embankment fill calculation related to mechanical parameters table

表8 新路堤填土相关计算力学参数表
Tab.8 New embankment fill calculation related to mechanical parameters table

图5 纤维掺量与安全系数及特征点位移、应力关系曲线<br/>Fig.5 Fiber blending capacity and safety factor,characteristic point displacement and stress curve

图5 纤维掺量与安全系数及特征点位移、应力关系曲线
Fig.5 Fiber blending capacity and safety factor,characteristic point displacement and stress curve

图6 不同养护龄期下安全系数与纤维掺量关系曲线(L=6 mm,K= 8 m)<br/>Fig.6 Relationship between safety factor and fiber content under different curing ages(L=6 mm, K=8 m)

图6 不同养护龄期下安全系数与纤维掺量关系曲线(L=6 mm,K= 8 m)
Fig.6 Relationship between safety factor and fiber content under different curing ages(L=6 mm, K=8 m)

图7 不同坡度系数下安全系数与扩宽度关系曲线(H=5 m)<br/>Fig.7 Relationship between safety factor and expansion width under different slope coefficients(H=5 m)

图7 不同坡度系数下安全系数与扩宽度关系曲线(H=5 m)
Fig.7 Relationship between safety factor and expansion width under different slope coefficients(H=5 m)

图8 路堤坡度系数与安全系数关系曲线<br/>Fig.8 Curve of embankment slope coefficient and safety factor

图8 路堤坡度系数与安全系数关系曲线
Fig.8 Curve of embankment slope coefficient and safety factor

图9 不同坡度系数下安全系数与路堤高度关系曲线(K=6 m)<br/>Fig.9 Relationship between safety factor and embank ment height under different slope coefficients(K=6m)

图9 不同坡度系数下安全系数与路堤高度关系曲线(K=6 m)
Fig.9 Relationship between safety factor and embank ment height under different slope coefficients(K=6m)

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备注

引言

1 试验材料

2 试验内容

3 试验结果与分析

4 试验结果与分析

5 扩宽路堤边坡稳定性分析

6 数值模拟算例结果及分析

7 结论

期刊信息