采用强度折减法对两个高度分别为60m和40m的上工格栅加筋高边坡的设计断面进行稳定分析,综合考虑塑性区贯通、特征点位移突变、计算不收敛,以及土工格栅的容许抗拉强度等确定相应的安全系数。计算表明采用不同的破坏标准,强度折减法会得到不同的安全系数;如果筋材强度始终得到保证,单纯由土材料的强度损失诱发边坡失稳,这种情况对应的安全系数是比较高的。考虑筋材强度,边坡会在较小的折减系数下因为筋材强度不足而失稳。有限元法能够得到不同情况下各层筋材的受力情况,可以据此进行加筋力的分配,这是极限平衡法所不具备的。
The strength reduction method is employed to study the stability of two geogrid reinforced soil slopes. The heights of the slopes are 60 m and 40 m, respectively. Safety factors are calculated according to the criteria of run-through of plastic zone, displacement mutation of feature point, convergence of iteration and allowable tensile strength, respectively. The results show that different safety factors may be achieved in the light of different criteria for failure. Larger safety factor may be obtained if the strength of the reinforcement is high enough and the slope instability is merely induced by the reduction of soil strength. The slope may fail at lower reduction factor owing to the insufficient strength of reinforcement. The tensile stress in each layer of reinforcement can be obtained by means of the finite element method and be used to assign the reinforcement strength required, while the limit equilibrium method is not available in this case.