兰州地区黄土的冻结温度  

Freezing Point of Loess in Lanzhou,China

作　　者：邱国庆[1] 王雅卿[1] 曾凯文 盛文坤[1] 

机构地区：[1]中国科学院兰州冰川冻土研究所

出　　处：《冰川冻土》1990年第2期105-115,共11页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金

摘　　要：兰州东岗镇剖面下部黄土的冻结温度T_f与土的含水量W和Na^+与Cl^-含量(mmol/100g)有以下的相关关系:T_f=-4.27W^(-1.03)[NA^+]^(0.54)[Cl^-]^(0.48)。在冻结开始瞬间,可认为W等于未冻水含量W_u,T_f等于土温T,于是此式可改变为Anderson-Tice公式的形式:W_u=40.53│T│^(-0.98),据Tice等人的实验资料,对兰州九洲台剖面黄土,有W_u=30.21│T│^(-0.97);而对于兰州白塔山剖面黄土,有W_u=26.47│T│^(-0.98),这些来源不同而结果相近的式子,说明含盐量与第一个系数的关系比之它与T的指数的关系更为密切。The loese obtained from the lower part of the profile in Donggangzen, Lanzhou was applied to be the material for freezing test. The freezing points of soil samples which are different in dry density .water content and salinity were measured. After eliminating progressivly the unimportant factors according to the standard regression coefficient, the final result of regression analysis shows that the freezing point Tf (℃) of soil depends mainly on the water content W(%)and contents of Na+and Cl-(in mmol / 100 g soil): Tf=-4.27W-1.03[Na+]0.54[Cl-]0.48 (1) There are 3 inferences derived from Equation (1). A. At the beginning moment of freezing process, W is equal to unfrozen water content Wu, and Tf is equal to soil temperature T,therefore Equ.(l) can be changed in the form of Anderson-Tice Formula: Wu = 40.53|T|-0.98 (2) Based on Tice 's data by NMR (Nuclear Magnetic Resonance method for determining the unfrozen water content), the regression equation for loess of Jiuzhoutai profile,Lanzhou can be given as Wu = 30.21|T|-0.97 (3) for the loess of White Pagoda Hill, Lanzhou, it gives Wu = 26.47|T|-0.98 (4) The fact that Equations (2), (3) and (4) whilch resulted from different point are similar to each othershows that Equ .(1) conforms to the regulation known previously and implies that the power of T might depend mainly on the composition of particle sizes , the other coefficient might depend mainly on salinity. B. Also the Anderson-Tice formula can be changed into the freezing point Formula,e.g. (3) can be Tf=-33.56W-1.03 and (4) can be Tf=-28.30W-1.02. C. The dry and saline loess at high possition may not be frozen as deep as 1.03m of the measurement at the meteorological station.In some places, it may be frozen in a short period in Winter.

关 键 词：冻结温度 回归分析 黄土 冻土 

分 类 号：P642.131[天文地球—工程地质学] P642.14[天文地球—地质矿产勘探]