土工格栅加筋路堤影响因素研究

Research on Effecting Factors of Embankment Reinforced with Geogrid

在野外修筑了4段连为一体的试验路堤,其中3段含土工格栅加筋层,格栅层间距各不相同.用土压力盒测量了每段路堤底部的竖向土压力.在试验研究的基础上建立有限元模型,模型得到了试验数据的验证.用该模型对土工格栅加筋路堤进行了计算分析,探讨了加筋层间距以及路堤土的内摩擦角、粘聚力和弹性模量对加筋路堤沉降和应力分布的影响规律.得到以下主要结论:(1)加筋路堤的表面沉降随格栅层间距的减小而减小,其根本原因是加筋路堤内部的竖向应力随格栅层间距的减小而降低,而水平应力却随之增加;(2)加筋路堤的整体性和竖向变形的均匀性随格栅层间距的减小而提高,这有利于改善路面结构的受力和变形条件,从而延长路面的使用寿命.

An experimental embankment is constructed including 4 sections, three of which are reinforced by geogrid with different reinforcement spacing, the other is without reinforcement. The vertical earth pressures under each section of the embankment are measured by earth pressure ceils. Based on the experimental study, a finite element model is presented, the results calculated by which are compared with the test data. A series of numerical analyses are carried out to examine the effect of reinforcement spacing, the internal friction angle, cohesion and modulus of embankment soil on the surface settlement and stress distribution of geogrid-reinforced embankment. The following main conclu- sions are obtained：（1） The surface settlement of a geogrid-reinforced embankment is decreased with decreasing of the reinforcement spacing because of the vertical stress＇ decreasing and the lateral stress＇ increasing at the same time. （2） Small differential vertical displacement occurs across the section of geogrid-reinforced embankment when the reinforcement spacing is smaller enough. This is helpful to the pavement for having an even supporting by the subgrade and a longer service time.