考虑颗粒破碎特性的机场高填方变形与稳定性分析

Deformation and stability analysis of airport high coarse-granular fills considering particle breakage characteristics

近年来,中国西南山区的机场高填方建设进入快速发展阶段,具有良好工程特性的堆石料等粗粒土广泛应用于高填方。机场高填方内部应力较高,粗粒土等填筑材料会产生颗粒破碎,分析颗粒破碎特性对高填方变形和稳定性的影响具有重大工程意义。使用离散元颗粒流法对高填方建立数值模型,采用强度折减法模拟了高填方的变形演化过程,利用Russell和Muir Wood颗粒破碎准则,对颗粒破碎和颗粒不破碎两种情况分别进行了离散元的数值模拟分析,对比研究了考虑颗粒破碎对高填方变形和稳定性的影响。研究结果表明:粗粒土颗粒破碎后产生的小颗粒将滑移充填颗粒间的空隙,使高填方变形量增加,高填方土体的抗剪强度降低,进而使高填方的安全系数降低,严重影响高填方的稳定性。

In recent years,the airport high coarse-granular fill construction in the southwest mountain area of China has entered a stage of rapid development,and coarse-grained soils such as rockfill materials with comparatively good engineering characteristics are widely used in high coarse-granular fill.The internal stress of high coarse-granular fill is large,and coarse-grained soil will cause particle breakage.It is of great engineering significance to analyze the impact of particle breakage characteristics on the deformation and stability of high coarse-granular fill.Modeling high coarse-granular fills using discrete element particle flow method.The deformation evolution process of the high coarse-granular fill is simulated through the strength reduction method.Based on the Russell & Muir Wood particle breakage criterion,two cases of particle breakage and don’t breakage were simulated and analyzed respectively.In addition,we also focus on the effect of particle fragmentation on the deformation and stability of the high coarse-granular fill.DEM modelling results indicate that the small-size grains abraded from the host coarse-granular grains will slip and fill the gaps among the host grains,leading to an increase in deformation and a decrease in the shear strength,and further resulting in a decrease in safety factor and stability of high coarse-granular fill.