摘要
基于拉曼光时域反射计(ROTDR)技术,提出了冻土瞬态温度场的分布式光纤监测方法。应用该方法对初始含水率分别为20%,40%与60%的下蜀土试样在一个冻融循环内的瞬态温度场进行了实时监测;获得了监测数据的时空矩阵;提取出未冻土、正冻土、正融土与融土瞬态温度场的多项形态分布,包括局部形态分布、负温边界形态分布、既定位置形态分布以及既定时刻形态分布等;识别出环境负温骤升行为对冻土瞬态温度场形态分布的扰动特征;表明了传感光纤护套对其温度响应具有延迟效应。试验结果还表明:正冻土温度变化速率与其初始含水率间存在反相关性,而正融土温度变化速率与其初始含水率间无单调相关性。
A monitoring method for transient temperature field of frozen soil using distributed optical fiber sensors was developed based on Raman optical time-domain reflectometry （ROTDR）. Three Xiashu soil specimens with their respective water content of 20%, 40% and 60% were monitored under a cycle of freezing and thawing, when the method was employed in real time. A space-time matrix of the monitored data was obtained. Several distribution features of the transient temperature field, including local distribution, negative temperature boundary distribution, specific-position distribution and specific-time distribution, were extracted from the matrix in the respective phases of unfrozen soil, freezing soil, thawing soil and thawed soil. The disturbed feature resulted from an abrupt temperature rising of the environment was identified. It was discovered that the coating of sensing fiber resulted in a lagging effect of temperature response. It was also shown that there was an inverse correlation between the speed of temperature variation and the initial water content for freezing soil, but no monotonic correlation for the thawing soil.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2007年第5期723-728,共6页
Chinese Journal of Geotechnical Engineering
基金
国家杰出青年科学基金资助项目(40225006)
国家自然科学基金资助项目(40572154)
关键词
冻土
瞬态温度场
拉曼光时域反射计
时空矩阵
温度变化速率
frozen soil
transient temperature field
Raman optical time-domain reflectometry
space-time matrix
speed of temperature variation
