Abstract:In order to further reveal infiltration mechanism of intermittent infiltration of layered soil under surge irrigation, through the analysis of experimental data and theoretical research, Brook-Corey and Green-Ampt (BC-GA) improved infiltration model of layered soil under intermittent infiltration of surge irrigation was built. Relationship between water suction and wetting depth of intermittent wetting front of layered soil was built, which showed that the suction value Sf was decreased with the increase of wetting depth zf. Soil saturated hydraulic conductivity, retained moisture content, intake suction value, water conductivity coefficient, shape coefficient and depth change in the sand layer were proved to be the main influence parameters of migration distance of layered soil under intermittent infiltration. When the number of cycles was increased, the saturated hydraulic conductivity of the upper soil was decreased, saturated water moisture content was reduced and the suction was increased. Only the intake suction value in the sand layer was increased with the increase of cycle number. Calculation of intermittent infiltration characteristics and wetting front migration characteristics of sandy soil with different burial depths based on BC-GA model pointed out that the cumulative infiltration amount under the same sand layer depth was decreased and the wetting front migration distance under the same sand layer depth was increased. The cumulative infiltration volume and the wetting front was increased under the same water supply period. When the water supply period reached the maximum, the buried depth of the sand layer would reduce the cumulative infiltration amount and the wetting front migration distance. The research result could lay a scientific foundation for further development of surge irrigation technology.
