基于主动加热型FBG的土体干密度原位测量方法研究  

Feasibility study on actively heated FBG methods for dry density measurement

作　　者：刘洁 孙梦雅 施斌[1] 魏广庆 郭君仪 郑兴 LIU Jie;SUN Meng-ya;SHI Bin;WEI Guang-qing;GUO Jun-yi;ZHENG Xing(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China;NanZee Sensing Technology,Ltd.,Suzhou 215123,China)

机构地区：[1]南京大学地球科学与工程学院,江苏南京210023 [2]苏州南智传感科技有限公司,江苏苏州215123

出　　处：《岩土工程学报》2021年第2期390-396,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金重点项目(41230636);国家重大科研仪器研制项目(41427801)。

摘　　要：针对现有干密度原位测量技术的局限性,提出了一种基于主动加热型FBG的土体干密度原位测量方法(简称H-FBG干密度法),该法通过土体的导热系数,建立温度特征值(T_(t))与干密度ρd之间的关系,进而对干密度进行原位测量;在室内试验的基础上,讨论了该方法的最优加热参数,研究了土类型与含水率对测量结果的影响,证明了该方法的可行性。试验结果表明:T_(t)随着ρd增加而降低,指数函数模型相较于幂函数模型和线性模型的T_(t)-ρd曲线拟合效果要好;H-FBG干密度法最优加热参数为15W/m和5min;高含水率土体受微观结构的影响,随着ρd增加T_(t)变化率减小。An in-situ method based on the actively heated fiber Bragg grating for monitoring dry density is proposed(abbreviated to H-FBG)to make a progress in the existing technique.The relationship between the temperature characteristic value(Tt)and the dry density(ρd)is established through the thermal conductivity for the in-situ monitoring of the dry density.A series of indoor tests are carried to verify the feasibility of the method,the effects of moisture content and types of soils are discussed,and the heating parameters are determined.The results show that Tt decreases with the increasingρd,and it is described well using the exponential function.15 W/m and 5 min can be the best heating parameters applied for the measurement.The temperature of the soils with a higher water content decreases slowly owing to the effects of micro-structure of soils.The results may provide the theoretical and technical foundation for the further application of the proposed method.

关 键 词：H-FBG干密度法 土体 原位测量 特征值 导热性 

分 类 号：TU41[建筑科学—岩土工程]