Effect of Accelerated Physical Weathering of Coarse Soils and Wetting and drying Cycle on Some Soil Physical Properties

Abstract

soil samples were collected in May the 5th, 2021 from wadi Al-Muhammadi) Al-Mohammadi valley(in Al-Anbar governorate in western Iraq. The trail consisted of four treatments. In the first treatment, the sample Is passed through a 2000 μm metal sieve, while in the fourth treatment the sample is crushed or milled to size 70μm sieve. In the second treatment, the mixture ratio of soil was 25:75 (natural: Crushed). In the third treatment, the mixture ration of soil was 50:50 (natural: crushed). This paper determined in the soil coefficients for penetration, the density sustainability, soil porosity, as well as scanning soil aggregates using an electronic microscope samples passed through cycle of wetting and drying the results showed that the decrease was evident in soil penetration resistance in recent cycles in conjunction with the decrease in soil bulk density significant because of mechanical pulverization and cycles of wetting and drying along with an increase in soil porosity. the proportion of soil cracks resulting from shrinkage and swelling has been calculated and It was found that it increases with the percentage of clay in the soil. The electron microscope images show the soil was influenced by the mechanical pulverization during the first three cycles, as for the wetting and drying cycles, their effect appeared in the last cycles, the partial transformation of mica to mineral 2:1 was observed with the progression of wetting and drying cycles.