摘要
寒区土壤冻结深度的观测以往多采用丹尼林冻土器进行人工测量,由于受到天气、地形、低温和人为等因素的影响,往往难以开展。现多采用垂直埋管的方式对地温温度场进行测量,间接确定土壤冻结深度。本文以4种常用管材(铁管、PVC管、PMMA管、PPR管)为研究对象,分析了不同材质的垂直埋管对地温和冻结深度变化测量的差异性,得到如下结果:(1)冻融周期内,铁管、PVC管、PMMA管、PPR管测得的地温温度场有阶段性差异,土壤冻结前期和融化期差异较小,冻结稳定时期差异明显扩大,40~120 cm土层出现持续稳定差异,直接导致各管计算冻融深度的差异。(2)计算各管冻融深度过程中,冻结期采用线性内插冻融层面间起始冻结温度获得冻结锋面变化,融化期通过内插和线性外延土层温度场确定上下融化锋面变化,相比于传统内插温度场计算得到冻融深度变化的方法,能够更为真实地反映了土壤的冻结状况。(3)利用上述方法对4种不同材质管材的温度场测量结果进行插值分析,并将各管计算冻结融化深度与实际状况进行比较,得出保温材料插值计算冻深值偏小,冻融周期减少8~13 d,利用铁管温度场计算冻深值平均偏大约7.5 cm,但较保温材料能够更为精确反映土壤的冻结融化过程。(4)利用Stephen经验公式计算了试验场区冻融状况,绘制了计算冻融过程线,整个冻融过程结果与校正后人工观测结果基本吻合。
Denillin freezing meter was often used to monitor soil frozen depth in cold area, but manualmeasurement was easily influenced by the factors of weather, terrains, low temperature, human etc. Verti-cal buried pipes are always chosen to measure soil temperature field for confirming frozen depth indirectly.With the purpose of exploring the influence of different pipes（iron pipe, PVC pipe, PMMA pipe andPPR pipe） on measuring soil temperature and frozen depth, diversity of measurement results is analyzed.（1） Differences exist among the measured ground temperatures of the different pipes： smaller in the earlyfreezing and thawing stage, and enhanced in the stabilization freezing stage obviously. A steady differenceof soil temperature,which leads to a variability in calculating freezing-thawing depth,is found in the 40～120 cm layer.（2） The method, getting freezing front depth by interpolating-0.15° C isothermal on thefreezing and thawing layer in freezing period and obtaining thawing depth through linear extending 0°C iso-thermal on the thawing layer in thawing period,makes the calculation thawing point more accurate and re-flects the real condition of the freezing-thawing process of soil preferably in comparison with traditional in-terpolation.（3） There is a little difference in measuring freezing-thawing depth by using the method men-tioned above. The frozen depth of PVC, PPR and PMMA（thermal insulation material） pipes are smallerthan the actual condition,where the difference is remarkable. The thawing time of different pipes is 8～13days ahead of time in comparison with the revised freezing-thawing process. The iron pipe is a better pipewhich has a high precise in reflecting the freezing condition through the difference analysis,the average de-viation is 7.5cm in the freezing period.（4） The Stephen empirical formula is adopted in calculating thefreezing-thawing process of the test area,and the results verify the accuracy of the manual observation.
作者
汪恩良
张安琪
包天鹅
刘兴超
WANG Enliang ZHANG Anqi BAO Tiane LIU Xingchao(School of Water Conservancy and Civil Engineering, Northeast Agricultural University, Harbin 150030, China)
出处
《水利学报》
EI
CSCD
北大核心
2017年第1期86-95,共10页
Journal of Hydraulic Engineering
基金
国家自然科学基金项目(51541901)
黑龙江省博士后基金(LBH-Z13031)
哈尔滨市优秀学科带头人计划(2014RFXXJ103)
关键词
寒区
冻深测量
温度
插值法
差异性分析
cold area
frozen depth measurement
temperature
interpolation
variability analysis
作者简介
汪恩良（1971-），男，河北滦南人，博士，教授，主要从事工程冻土和水工建筑物冻害防治研究。E-mail：HLJWEL@126．com
