筋土界面特性是加筋土结构设计的重要技术指标,是揭示土工合成材料加筋机理的关键。采用GDS界面剪切仪研究了剪切速率、竖向应力及网孔尺寸对土工格栅与饱和细砂界面特性的影响。试验结果表明:剪切速率较小(≤1.0 mm/min)时,剪切速率对界面抗剪强度影响不大;剪切速率在1.0~10 mm/min范围内,随着剪切速率的增大,界面抗剪强度先增大后减小;界面抗剪强度随着竖向应力的增加而增大,竖向应力增强了土工格栅对土颗粒的嵌锁作用,限制了土颗粒的剪切移动,从而提高了土体的抗剪强度;剪切速率为1.0 mm/min,竖向应力较小(50~100 kPa)时,小网孔尺寸土工格栅加筋效果更明显;剪切速率为0.1 mm/min,竖向应力较大(200~300 kPa)时,大网孔尺寸土工格栅加筋效果更明显。研究结果对土工格栅在加筋土中的应用具有参考价值。
Abstract
As pivotal technical indicators in designing geosynthetic and reinforced soil structures, the properties of interface between soil and reinforcement reveal the reinforcement mechanism of geosynthetics. In the present study, the influences of shear rate, vertical stress, and geogrid's mesh size on the performance of interface between geogrid and saturated fine sand were investigated using GDS interface shear apparatus.Results revealed that 1) Small shear rate (≤1.0 mm/min) had only slight impact on the shear strength of interface. 2) When shear rate ranged between 1.0 and 10 mm/min, the shear strength of interface increased initially but decreased afterwards with the growth of shear rate. 3) The rising of vertical stress enhanced the shear strength of interface by intensifying the interlocking effect of geogrid on soil particles and limiting the shear displacement of soil particles. 4) When shear rate was 1.0 mm/min and vertical stress was small (50-100 kPa), geogrid with small mesh size was more effective in reinforcement; when shear rate was 0.1 mm/min and vertical stress was large (200-300 kPa), geogrid with large mesh size was of better reinforcement effect. The results can facilitate the application of geogrids in reinforced soil.
关键词
土工格栅 /
饱和细砂 /
界面特性 /
界面剪切试验 /
剪切速率 /
网孔尺寸
Key words
geogrid /
saturated fine sand /
interface properties /
interface shear test /
shear rate /
mesh size
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基金
:山东科技大学科研创新团队资助项目(2015TDJH104)
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