不同筋材刚度下加筋土挡墙离心模型试验

加筋土挡墙由于优良的力学性能、低廉的造价、更好的地形适应性,已经越来越广泛地被应用于各种工程。但其在正常工作状态下的真正工作机理尚不完全清楚,目前的规范设计指南并不能反映加筋土挡墙内部应力真实分布情况。为了研究不同筋材刚度对加筋土挡墙性能的影响,通过土工离心试验监测了土工格栅应变、面板水平位移和土压力。试验结果表明:采用小刚度筋材时,筋材的变形更加显著,但对竖向土压力的分布基本没有影响;靠近面板区域的土压力都远小于理论值,格栅最大应变出现在墙的中下部;对于面板连接处的筋材应变不能简单地用传统土压力理论解释,还需考虑填土不均匀沉降引起的面板对加筋土拉拽作用等其他影响因素。试验结果可为正常工况下加筋土挡墙工作性能与筋-土相互作用机理的研究提供参考。

Centrifuge Tests of Reinforced Soil Retaining Wall withDifferent Reinforcement Stiffness

Reinforced soil retaining wall has been widely used in various projects because of its excellent mechanical properties, lower costs and better terrain adaptability. However, its real mechanism under working stress condition is not completely clear and current design guidelines could not reflect the real stress distribution in reinforced retaining wall. In order to research the behavior of reinforced retaining wall with different reinforcement stiffness, we monitor geogrid strain, horizontal displacement of facing, and earth pressure by geotechnical centrifuge tests. Results indicate that the deformation of reinforcement is more significant when using reinforcement of small stiffness,while the distribution of vertical earth pressure along the potential sliding surface is barely affected by stiffness. In both models, earth pressure adjoining to facing panel is much lower than theoretical value, and the maximum strain of geogrid appears in the mid-lower part of wall. Traditional earth pressure theory could not simply explain the reinforcement strain at panel connections. We should also take into account the pulling effect between panel and reinforced soil induced by differential settlement of backfill and other factors. The tests results offer reference for researching the behavior of reinforced soil retaining wall and the mechanism of interaction between soil and reinforcement under working stress conditions.