块石细长比对土石混合体边坡稳定性的影响

Effects of rock’s elongation on stability of rock-soil-mixture slope

作为一种非均质岩土介质材料,土石混合体的宏观力学性质与内部块石细观结构密切相关。首先,基于单元初始应力赋值法,利用FLAC 3D内置FISH语言在较短的时间内计算出边坡安全系数,为后续探明块石细长比对土石混合体边坡稳定性的影响奠定了基础。接着采用上述方法对土石混合体边坡稳定性进行分析,发现块石细长比对土石混合体边坡剪切带和稳定性有较大的影响。随着块石细长比增加,一方面,剪切带的扩展形态由沿块石长轴两侧的土石界面分散分布逐渐过渡到沿潜在滑动面方向多级分布,且逐渐向坡顶延伸而形成贯通的剪切带后,边坡发生局部分级破坏;另一方面,边坡安全系数逐渐减小,表明块石细长比对边坡稳定性的影响越来越小。

As a representative heterogeneous material,macroscopic mechanical behavior of soil-rock-mixture is closely related with internal mesostructure of it.In order to prove the impact of the stability of the slope of the mixture of soil and stone,the FLAC 3D built-in FISH language is used to calculate the slope safety factor in a shorter time through the initial stress assignment method of the unit.On the basis of that,these models were used to analyze the stability of the soil-rock-mixture slope by the method of strength reduction finite difference that was self-improved,and obtained effect’s feature of shear band and slope stability for soil-rock-mixture slope caused by difference in rock’s elongation.As the rock’s elongation increases in the slope,on the one hand,extension forms of the shear band in slope had changed from dispersive distribution of the earth-rock interface along the long axis of the rock to hierarchical distribution along with potential slip surface,and gradually extends to the top of the slope to form a penetrating shear zone causing gradually failure of slope,on the other hand,safety factor for slope gradually decrease,and the rate of change also becomes slight,which demonstrates the influence of rock’s elongation to slope stability become insignificant.