基于自感测的机敏格栅加筋膨胀土边坡服役性能演化与评估研究

Geogrid as a reinforced material has been successfully used in the treatment of expansive soil slope. But the research on the reinforcement mechanism and the design theory is lagging behind the engineering practice. The monitoring and evaluation of the service performance of geogrid reinforced expansive soil slope under the complex environment is an urgent problem to be solved. Based on the force-sensitivity effect of the flexible conductive film, a new smart geogrid with distributed deformation self-sensing function is developed. The geogrid showed the double effect of soil reinforcement and deformation monitoring.The force sensitive characteristics of smart geogrid is studied.The characteristic of deformation of reinforced expansive soil undergoing cycles of wetting and drying is studied.The relation between deformation of reinforced expansive soil and flexible conductive film sensing information is built. The performance of the geogrid-soil interaction is studied by pull-out test. Then evolution characteristics of the service performance of the geogrid reinforced expansive soil slope are studied by slope model test and numerical simulation. Finally,evaluating service performance of reinforced slope is setup based on flexible conductive film sensing information . The outcomes of the research may prove useful in the construction and safety condition diagnosis of reinforced expansive slope projects. The new technique will bring great benefits in engineering and environmental protection.

土工格栅作为一种加筋材料已经成功应用于膨胀土边坡处治中，但加筋机制和设计理论方面的研究落后于工程实践，复杂环境下格栅加筋膨胀土边坡服役性能的监测与评估是亟待解决的课题。本项目基于柔性导电膜的力敏效应，研发具有分布式变形自感测功能的机敏土工格栅，将其应用于膨胀土边坡处治，不仅起到加筋作用，同时也监测柔性加固的膨胀土边坡性能演化与稳定性。项目研究机敏土工格栅的力敏特性；研究干湿循环作用下加筋膨胀土的变形特性，建立加筋膨胀土变形与导电膜感测信息对应关系；通过拉拔试验，研究筋土界面特性；通过边坡模型试验和数值模拟，研究荷载、干湿循环作用等环境下加筋膨胀土边坡服役性能演化特征；建立基于导电膜感测信息的加筋膨胀土边坡服役性能评估的模型。项目的研究为加筋膨胀土工程的设计与施工提供科学依据，为加筋膨胀土工程安全状态诊断提供了新的技术手段，具有重要的理论意义和工程应用价值。

本项目基于柔性导电膜的力敏效应，研发了具有分布式变形自感测功能的机敏土工格栅，将其应用于膨胀土边坡处治。项目的研究具有重要的理论意义和工程应用价值。本项目通过理论分析、室外试验和数值模拟相结合的手段，完成的研究工作和取得的成果如下：（1）通过拉伸试验，得到的机敏土工格栅拉伸过程中的应力-应变关系曲线，研究了机敏土工格栅的力敏特性，对机敏土工格栅的应变灵敏系数进行了标定；（2）通过一系列的室内试验，建立了膨胀土的胀缩性与导电膜电阻变化率，光纤应变等信息对应关系。通过室内拉拔试验和数值仿真，研究筋土相互作用特性，得到了筋土界面参数。（3）通过边坡模型试验，研究荷载、干湿循环作用等环境下加筋膨胀土边坡服役性能演化特征。采用数值模拟软件，分析了土工格栅间距等参数对加筋膨胀土边坡服役性能的影响。（4）在试验的基础上，结合数值模拟，提出了加筋边坡服役性能的评估方法。建立了电阻变化率、应变值与加筋边坡安全系数之间的关系，采用有限元软件评估了加筋膨胀土边坡服役性能。