空间与颗粒参数对块石土边坡稳定性影响数值模拟研究

Analysis of Space and Particle Parameter Influence to Stability of Soil-rock Mixture Slope

块石土边坡具有物理力学性质复杂、非线性强等特性,受块石–土体空间分布、块石粒径等几何因素影响较大。为研究空间与颗粒参数对块石土边坡稳定性影响,基于已有的块石形状数据库随机生成方法,采用ABAQUS软件非线性分析方法,考虑含石量、最大粒径、空间分布等多种几何因素,建立大量有限元模型进行计算分析。结果表明:含石量增大,边坡安全系数上升,且含石量在50%~60%区间内上升速率最快;含石量增大,同粒径组边坡安全系数标准差增大,模型安全系数差异变大。最大粒径增大,块石分布对于边坡安全系数的影响增大,边坡稳定性先减小后增强,同粒径组边坡安全系数标准差增大。含石量和最大粒径增大,块石空间分布对于边坡稳定性影响增大。粒径大小、块石空间分布对于块石土边坡稳定性影响方式也不同,大粒径块石存在令滑动面向边坡内部发展,而密集小粒径块石大多是令滑面呈折线形,二者皆可增大边坡稳定性。当块石长轴与坡面夹角为90°、135°时,边坡塑性区呈发散分布,滑面更靠内部,稳定性更好;当块石长轴与坡面夹角为0°、45°,则与上述情况相反。在通常沉积条件下,边坡稳定性随长短轴比增加而降低,滑动面越发平滑,塑性区范围也更加集中。研究结果表明,几何参数不同,边坡稳定性差异较大,且具有一定规律性,在实际工程中有一定的参考价值。

The soil-rock mixture slope has the characteristics of complex physical and mechanical properties and strong nonlinearity,which is greatly affected by geometric factors such as the rock distribution and rock particle size.In order to investigate the effect of geometric parameters on the stability of soil-rock mixture slopes,the ABAQUS software nonlinear analysis method was utilized based on the random generation method of block-shape database proposed by the team.Considering a variety of geometric influencing factors such as the rock content,maximum rock particle size and rock distribution,a large number of finite element models for calculation and analysis were established.The results showed that the safety factor of slope increased with the increase of rock content and the increasing rate was largest when the rock content was in the range of 50%~60%.With the increase of rock content,the standard deviation of the safety factor of the slope in the same particle size group and the difference of model safety factor increased.With the increase of the maximum particle size,the impact of the rock distribution on the safety factor of the model and the standard deviation of the safety factor of the slope in the same particle size group increased,the stability of the slope first decreased and then increased.With the increase of rock content and maximum particle size,the influence of rock distribution on slope stability increased.The influence of the rock distribution on the stability of the soil-rock mixture slope varied with the rock particle size.The existence of large size rock made the sliding face the move away from free face of slope,while the dense small size rocks mostly made the sliding face hackly,both of which increased the stability of the slope.When the rock long axis and slope angle was 90°or 135°,the plastic zone of slope was divergent,the sliding surface was more internal,and the slope stability increased.When the angle between the long axis of the block stone and the slope was 0°or 45°,it was contrary to the above situation.Under normal sedimentary conditions,slope stability decreased with the increase of the ratio of axial length to axial length.The sliding face became smoother and the plastic zone became more concentrated.It can be concluded that the rock content,rock particle size and rock distribution had great influences on the slope stability.With different geometric parameters,slope stability varied greatly and had a certain regularity,which was of certain reference value to the practical projects.