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顺层边坡是一类包含层面和其他类型结构面影响的复杂边坡,其安全系数计算一直是个难题。笔者结合离散单元法与强度折减法对顺层边坡安全系数的计算过程和计算效果进行了探讨。用Fish语言编写了能在UDEC下执行的强度折减程序。在此基础上,探讨了刚度系数、层厚、层面倾角、层面内摩擦角、层面粘聚力、开挖坡角等因素对某高速公路典型顺层边坡稳定性的影响机制。计算结果表明:刚度仅对塑性区影响较大,对安全系数影响不大;层厚的增加对安全系数影响较小,但是随着厚度的增加变形破坏模式由楔形变为沿层面屈曲破坏;层面倾角接近破裂角时,安全系数降低(楔形滑动),反之则增加(屈曲破坏),直立时为倾倒破坏;强度参数增加,安全系数近于线性增加,破坏模式不变;开挖坡角增加,安全系数降低,破坏模式与层面倾角增加工况类似,安全开挖坡率不能大于1∶1.15。
The bedding slope is a kind of complex slope that contains the influence of the surface and other types of structural planes. The calculation of the safety factor has always been a difficult problem. The author combines the discrete element method and the strength reduction method to discuss the calculation process and calculation results of the safety factor of bedding slope. An Intensity Reduction program that can be executed under UDEC is written in Fish language. On this basis, the influence mechanism of stiffness coefficient, layer thickness, dip angle, internal friction angle, cohesion of layers, excavation angle and other factors on the stability of typical bedding slope of a freeway is discussed. The calculation results show that the stiffness has a great influence on the plastic zone and has little effect on the safety factor. The increase of the layer thickness has little effect on the safety factor. However, as the thickness increases, the deformation failure mode changes from wedge to buckling along the plane. When the inclination angle is close to the cracked angle, the safety factor decreases (wedge sliding), vice versa (buckling damage) and tilted upright; the strength parameter increases, the safety coefficient increases linearly and the failure mode remains unchanged; The safety factor is reduced, and the failure mode is similar to that of the increase of dip angle. The safe excavation slope can not be greater than 1: 1.15.