土工格栅与饱和细砂的界面特性试验研究
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摘要
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 k Pa)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 k Pa)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。
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.
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.
引文
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[17]张俊峰,王协群,邹维列,等.土-格栅界面强度参数和剪切刚度试验研究[J].长江科学院院报,2014,31(3):77-83.
[2] PALMEIRA E M. Soil-geosynthetic Interaction:Modeling and Analysis[J]. Geotextiles and Geomembranes,2009,27(5):368-390.
[3] LIU C N,JORGE G Z,CHEN T C,et al. Behavior of Gogrid-sand Interface in Direct Shear Mode[J]. Geotechnical and Geoenvironmental,2009,135(12):1863-1871.
[4] LIU C N,HO Y H,HUANG J W. Large Scale Direct Shear Tests of Soil/pet-yarn Geogrid Interface[J]. Geotextile and Geomembranes,2009,27(6):19-30.
[5] ABU-FARSAKH M,CORONEL J,TAO M. Effect of Soil Moisture Content and Dry Density on Cohesive Soil-geosynthetic Interactions using Large Direct Shear Tests[J].Journal of Materials in Civil Engineering,2007,19(7):540-549.
[6] ZHOU J,CHEN J F,XUE J F,et al. Micro-mechanism of the Interaction between Sand and Geogrid Transverse Ribs[J]. Geosynthetics International, 2012, 19(6):426-437.
[7] ARULRAJAH A,RAHMAN M A,PIRATHEEPAN J,et al. Evaluation of Interface Shear Strength Properties of Geogrid-reinforced Construction and Demolition Materials using a Modified Large-scale Direct Shear Testing Apparatus[J]. Journal of Materials in Civil Engineering,2013,26(5):974-982.
[8]刘飞禹,王攀,王军.不同剪切速率下格栅-土界面循环剪切及其后直剪特性[J].岩石力学与工程学报,2016,35(2):387-395.
[9]吴海,张涛,王攀,等.不同土工合成材料下新型加筋土界面特性[J].工业建筑,2015,45(8):104-109.
[10]赵占军.土工格栅拉拔特性及加筋土剪胀性试验研究[J].工业建筑,2016,46(3):88-92.
[11]王军,林旭,刘飞禹,等.砂土与格栅界面相互作用的直剪试验研究[J].岩土力学,2014,35(1):113-120.
[12]蔡剑韬.土工格栅加筋膨胀土拉拔试验研究[J].岩土力学,2015,36(1):204-208.
[13]徐超,廖星樾.土工格栅与砂土相互作用机制的拉拔试验研究[J].岩土力学,2011,32(2):423-428.
[14]徐超,孟凡祥.剪切速率和材料特性对筋-土界面抗剪强度的影响[J].岩土力学,2010,31(10):3101-3106.
[15]王建秀,黄天荣.双向土工格栅与中砂界面作用特性试验研究[J].建筑材料学报,2013,16(4):657-662.
[16]王家全,周健,黄柳云,等.土工合成材料大型直剪界面作用宏细观研究[J].岩土工程学报,2013,35(5):908-915.
[17]张俊峰,王协群,邹维列,等.土-格栅界面强度参数和剪切刚度试验研究[J].长江科学院院报,2014,31(3):77-83.