Seasonal freezing-thawing process and hydrothermal characteristics of soil on the Loess Plateau, China  

作　　者：CHOU Ya-ling WANG Li-jie 

机构地区：[1]Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Lanzhou University of Technology,Lanzhou 730050,China

出　　处：《Journal of Mountain Science》2021年第11期3082-3098,共17页山地科学学报（英文）

基　　金：This study was funded by the National Natural Science Foundation of China(grant number 51769013);the Basic Research Innovation Group of Gansu Province(20JR5RA478).

摘　　要：In seasonally frozen soil regions,freezing-thawing action and hydrothermal effect have strong influence on physical and mechanical behavior of shallow soil.A field experiment on the Loess Plateau in Northwest China was carried out to analyze the freezing-thawing process and hydrothermal characteristics of shallow soil considering the climate influence.The results show that the maximum seasonal freezing depth under bare ground surface in this area is from 20 cm to 50 cm.The ground temperature shows a similar changing trend with air temperature,but it has lagged behind the air temperature,and the ground temperature amplitude exponentially decreases with the increase of soil depth.The seasonally frozen soil has experienced four typical stages:unfrozen period,alternate freezing period,freezing period and alternate thawing period.The freezing-thawing process is characterized by unidirectional freezing and bidirectional thawing.The water content of shallow soil is significantly affected by air temperature,evaporation and precipitation,and the soil water content shows a"low-high-low"changing trend with the increase of depth.The soil temperature and water content interact with each other,and are often coupled.The variation trend of soil moisture with time is consistent with the change trend of the ground temperature with time in each soil layer,andthe degree of consistency is higher in the near surface soil than that in the lower layer.Also,the spatial-temporal characteristics of soil moisture and temperature is that the volumetric water content and ground temperatureof near surface soil have strong variability,and the range valueKa and coefficient of variation Cvof soil water content and ground temperaturein different seasons show a decreasing trend with the increase of depth.

关 键 词：Seasonally frozen soil Freezing-thawing process Hydrothermal characteristics Loess Plateau 

分 类 号：P642.14[天文地球—工程地质学]