Study on Compaction of Reclaimed Soil of Nonmetallic Mining Area in Northern Foothills of Tianshan Mountains in Xinjiang, China

This study focused on the changes of the compaction of the reclaimed soil after the reclamation process and the one-year maintenance period of the nonmetallic mines in north foothills of Tianshan Mountains in Xinjiang. The plate load experiment method was employed to simulate the compaction effect of various times of compaction from the reclamation machine on a different thickness of the reclaimed soil. The experimental data were analyzed by multivariate statistical analysis. The experimental results showed both compaction frequency and thickness of the reclaimed soil were key factors affecting the compaction of the reclaimed soil, and the interaction between them had a dramatic impact on the soil compaction. The difference of the porosity between the three-time compacted soil by the compaction machine and the noncompacted soil was significant. The effect of a single compaction dampened with the increasing times of compaction. The porosity of the 50cm and 70cm thick topsoil continuously decreases with the increasing times of compaction at the depth of 10cm from the surface soil. The porosity at the 30cm depth of the 50cm and 70cm thick topsoil decreased first and then increased with the increasing times of compaction. At the end of the one-year maintenance period, samples from different depths of the reclaimed soil of various thicknesses were collected to investigate the changes of porosity. The results showed the porosity of the reclaimed soil at different depths was changed due to irrigation. The porosity of the uncompacted soil decreased progressively from the surface to the deep region. The porosity of the compacted soil at the 10cm depth was lower than that at the 30cm depth due to soil sealing, whereas the porosity decreased with the increasing depth in the deeper region. The results from this study could provide a fundamental reference for the reclamation of nonmetallic mines in northern foothills of Tianshan Mountains in Xinjiang, China.