干旱区生态环境知识资源中心

Estimation of the thermal regime (i.e., the variation of soil temperature, theta, and heat flux, phi) in soilmass is a key issue in the realms of agronomy, forestry, ecology, micrometeorology, and geotechnical engineering. Usually, it is predicted by solving heat-conduction equations (HCEs) numerically and/or analytically by imposing assumptions such as (1) the sinusoidal variation in temperature (caused by the change in the ambience as a result of the solar cycle) at the top soil surface and/or (2) the uniform initial temperature of the soil mass. However, these solutions sometimes yield an improper thermal regime because of simplified assumptions that are not always suitable for natural soil surfaces. In this paper, the novel algorithm ATHERES (algorithm for thermal regime estimation in soils), which can be used for predicting thermal regime in sandy soil mass, is presented. The proposed approach eliminates the necessity for solving the HCE, and thus, the obtained thermal regime in sandy soil mass is free from the assumptions associated with conventional approaches. Performance of the proposed approach was demonstrated by using the results obtained from a series of laboratory tests on sandy soils of different particle sizes. The study reveals that the ATHERES is capable of incorporating naturally occurring temperatures and flux boundary conditions, including the initial condition of a nonzero thermal gradient. (C) 2017 American Society of Civil Engineers.