Three-dimensional reconstruction and quantitative characterization of reconstruction soil pore at opencast coal mine dump based on CT scanning

Soil pore plays an important role in migrating water and nutrient,the pore of reconstructed soil reflects the quality of reclaimed soil. In this paper,the reconstruction soil of different reclamation years at Antaibao opencast coal mine including 23 years,20 years and 0 years old and the soil of original landform were chosen to be scanned to obtain the information of soil pore. Soil pore distribution in three-dimension was reconstructed at matlab platform,then quantitative characterization was realized by searching the number of soil pore groups and the volume of each group. The soil porosity was also calculated. The results indicate that the porosity and connectivity of reconstructed soil had been significantly improved as reclamation years increasing. The condition of reclaimed soil pore of 23 years old is the best,the porosity of 50-75 cm layer is the largest,and its value is 23. 93% . The second one is the 20 years old soil,the porosity of 25-50 cm layer is the largest,and its value is 14. 58% . The connectivity of unreclaimed soil pore was the worst as compacted by the large mechanism. The porosity of three soil layers are all close to 3%,the distribution of the pore is relatively uniform. The number of pore groups and the volume of the largest pore group all have a good linear relationship with the porosity. With the increasing porosity,the number of the pore groups is decreasing,the volume of the largest pore group is increasing. The volume of pore groups is very small except the largest one. In order to improve the condition of pore of unreclaimed soil,the vegetation restoration should be carried out as soon as possible.