根系与格栅复合加筋土的力学特性试验研究

Experimental Study on Mechanical Properties of Composite Reinforced Soil with Root System and Grid

在土工格栅加固的边坡上种植生态植物,可以形成有效的生态护坡。为研究植物根系与土工格栅形成复合加筋土的力学机制,依托广西贵隆高速生态护坡工程,进行了素土、根系加筋土、格栅加筋土、根系与格栅复合加筋土的三轴固结不排水试验,对比分析了3种加筋土的力学特性。结果表明:植物根系、土工格栅均能提高加筋土的强度,其中根系与格栅的复合加筋效果最好;相较于素土、根系加筋土、格栅加筋土,根系与格栅复合加筋土的黏聚力分别增加了265.0%、101.0%、33.2%;保持最佳的土工格栅布置形式不变,根系与格栅复合加筋土的黏聚力随着含根量的增加出现先增后减的变化趋势,当含根量为0.5%时,黏聚力达到最大。对加筋土的三轴试验曲线进行分析,发现3种加筋土的应力-应变关系均符合邓肯-张模型,并获得了加筋土的邓肯-张模型参数,进一步通过试验数据对模型参数进行了验证。

Effective ecological slope protection can be achieved by planting ecological plants on slope reinforced by geogrid.The mechanical mechanism of composite reinforced soil consisting plant root system and geogrid is investigated via triaxial consolidation undrained tests on plain soil,root-reinforced soil,grid-reinforced soil,and root-grid composite reinforced soil with the ecological slope protection project of Guangxi Guilong Expressway as the research background.The mechanical properties of the three reinforced soils are also compared.Results demonstrate that both plant roots and geogrids can increase the strength of reinforced soil,while the composite reinforcement combining roots and geogrids has the best effect.Root-geogrid reinforced soil sees an increase by 265.0%,101.0%,and 33.2%in its cohesion,respectively,compared with plain soil,root-reinforced soil,and geogrid-reinforced soil.Under the optimum geogrid layout,the cohesion of root-geogrid reinforced soil first increases and then reduces with the rising of root content,and reaches its maximum when root content is 0.5%.Analysis on the triaxial test curves of the reinforced soils reveal that the stress-strain relationship of the three reinforced soils is in accordance with the Duncan-Chang model,and the Duncan-Chang model parameters of the reinforced soils are obtained and verified through test data.