加筋土边坡筋材拉力分布与分区

基于离心模型试验成果, 建立了不同坡高和坡度加筋土边坡有限元模型, 采用强度折减法计算了边坡安全系数达到1.30时的筋材最大拉力; 通过归一化筋材拉力和边坡高度, 分析了坡高和坡度对筋材拉力沿坡高分布的影响, 并结合实际加筋土边坡筋材拉力实测数据, 探讨了筋材拉力分布与分区。分析结果表明: 数值计算的边坡滑动面位置和形态以及破坏时的安全系数与离心模型试验结果吻合; 边坡高度对筋材拉力分布影响不大, 而坡度对其影响显著, 随坡度增大, 筋材最大受力区域由边坡中部逐渐向底部转移; 从总体筋材拉力分布来看, 边坡上部1/3和下部2/3高度范围内各层筋材最大拉力之和分别占总加筋力的1/4和3/4, 边坡上部所需的筋材拉力较小, 若按假定筋材拉力沿坡高均匀分布的1区方法进行总加筋力的分配, 会使得加筋土边坡下部的安全度降低; 宜按坡度进行加筋土边坡总加筋力的分区, 对于坡度不大于1.0∶1的边坡, 总加筋力按高度相等的3个区分配, 顶、中、底区加筋力分别为总加筋力的1/3、1/2、1/6, 对于坡度为1.0∶1~2.0∶1的边坡, 以其上部1/3高度为顶区, 下部2/3高度作为底区, 顶、底区加筋力分别为总加筋力的1/5、4/5, 而对于坡度不小于2.0∶1的边坡, 也等分为3个区, 顶、中、底区加筋力分别为总加筋力的1/6、1/3、1/2;可收集更多的实测数据充实筋材拉力数据库, 应对加筋土边坡加筋力按坡度分区方法进行进一步的完善和验证。

Distribution and zoning of reinforcement loads for reinforced soil slopes

Based on the result of centrifuge model test, the finite element models of reinforced soil slopes with different slope heights and angles were established.The maximum reinforcement loads in the slopes were calculated by using the strength reduction method when the safety factor was 1.30.The influence of slope height and angle on reinforcement load distribution along the height was analyzed by normalizing reinforcement load and slope height.Furthermore, thedistribution and zoning of reinforcement loads were discussed by combining with the measured reinforcement loads of field reinforced soil slopes.Analysis result shows that the computed location and shape of slope sliding surface and the safety factor at slope failure are in agreement with the centrifuge model experiment results.The distribution of reinforcement load is little influenced by slope height, whereas greatly influenced by slope angle.With the increase of slope angle, the location of maximum reinforcement load transfers from the mid height to the bottom of slope.According to the total distribution of reinforcement loads, the sums of maximum loads in reinforcement layers within the top 1/3 and the bottom 2/3 of slope account for 1/4 and 3/4 of total reinforcement tensile force, respectively.The upper part of slope requires less reinforcement loads.If using one zone method that assumes a uniform reinforcement load distribution along slope height to distribute total reinforcement tensile force, the lower degree of safety of slope will decrease.The total reinforcement tensile force of reinforced soil slopes can be distributed into zones according to slope angle. When the slope angle is no more than 1.0∶1, the total reinforcement tensile force can be distributed into three zones with equal height. The reinforcement tensile force within the top, middle and bottom zones account for 1/3, 1/2 and 1/6 of total reinforcement tensile force, respectively.When the slope angle is in the range from1.0∶1 to 2.0∶1, its upper 1/3 of height is regarded as top zone, and the bottom 2/3 of height is regarded as bottom zone.The reinforcement tensile force within the top and bottom zones account for 1/5 and 4/5 of total reinforcement tensile force, respectively.When the slope angle is no less than 2.0∶1, it can be also divided equally into three zones.The reinforcement tensile forces within the top, middle and bottom zones account for 1/6, 1/3 and 1/2 of total reinforcement tensile force, respectively. More measured data can be collected to enrich the database of reinforcement loads, so that the zoning method of reinforcement tensile force according to slope angle for reinforced soil slopes can be further completed and validated.