Sintering of Salt-affected Soils

A new method is proposed for soil improvement of salt-affected soils in regions where a sufficient amount of rainfall occurs in summer. The subsoil is made coarse by soil sintering, and the capillarity from groundwater is cut off. In this paper, basic experiments of soil sintering were conducted, based on the thermophysical properties of the salt-affected soils reported in previous papers. The results show that when the soil layer is deep, a long time is required for complete sintering. For instance, the time for the temperature at the 0.04 m in depth to reach maximum (960°C ) was 278 hr. This is fundamental fault of soils whose thermal conductivity (800°C) is small (e.g., 0.1 Wm−1K−1) and thermal diffusivity (800°C) is also small (e.g., 1.19×10−7 m×s−1). The soil should be dry as much as possible when sintering. If the soil water content decreased to 8.7% d.b. (dry) from 26.6% d.b. (wet), the required heating time to reach 960°C at the soil surface was saved to about 200 s from about 500 s.