徐州市铜山县柳新采煤塌陷复垦区的井工采煤区土地塌陷及复垦对土壤颗粒组成、土壤结构、容重等造成严重影响。借助激光粒度仪检测了塌陷地及其复垦土壤颗粒粒径分布,分别采用干筛和湿筛法对团聚体进行了筛分。运用分形原理研究了土壤的分形维数,并采用团聚体平均直径、破坏率、水稳性团聚体含量等指标分析了复垦对团聚体稳定性的影响。结果表明,土壤颗粒组成在塌陷地和未塌陷地区总体表现为上层到下层黏粒含量逐渐增加、粉粒逐渐减少;复垦对土壤颗粒组成进了重新分配,层次间表现明显紊乱特征。土壤分形维数变化范围在2.00~2.20之间,平均分形维数表现为未塌陷地〉复垦土壤〉塌陷地,分别为2.193、2.164、2.086,复垦土壤表现为复垦14 a〉复垦24 a〉复垦1 a。复垦过程中土壤水稳性团聚体比例、团聚体平均直径均有很大程度提高,且复垦时间越长,提高越大,水稳性团聚体破坏度逐渐降低,团聚体稳定性也逐渐增强。统计分析表明,土壤颗粒分形维数、土壤团聚体稳定性与土壤颗粒组成具有一定的相关性。复垦重建过程改善了塌陷地土壤状况,土壤颗粒组成、分形维数及团聚体结构趋于向正常土壤方向转变。
Land subsidence and land reclamation area have profound impact on soil structure, soil mechanical composition and water sports in Liuxin coal mine, Tongshan County, Xuzhou. Soil particle size distribution (SPD) fractal dimension was measured by laser diffraction particle size analyzer and soil aggregate was sieved by the method of dry sieve and wet- screening. Fractal theory was used to study the SPD fractal dimension, and factors such as soil aggregate average diameter, destruction rate, water-stable aggregates were analyzed to study the influence of the reclaimed aggregate stability. The research showed that in subsidence and no subsidence clay gradually increases and silt gradually decreases from the upper to the lower. The reclamation makes SPD redistributed, showing obvious chaos characteristics in the soil layer. SPD fractal dimension changes between 2.00 to 2.20, with SPD fractal dimension ranking as No Subsidence 〉 Reclamation 〉 Subsidence, 2.193, 2.164, 2.086, respectively, while the reclamation as Reclamation of 14 years 〉 Reclamation of 27 years 〉 Reclamation of 1 year. In the process of land reclamation, the water-stable aggregates proportion and aggregate average diameter have significantly improved, and the longer the time of reclamation, the greater the increase, the lower water-stable aggregates damage degree, the more durable the soil aggregates. Statistical analysis showed that SPD fractal dimension, soil aggregates stability and SPD has certain correlations. After the reclamation, the soils of the subsidence turn for the better, and SPD, fractal dimension and soil aggregate structure slightly enhanced in normal soil.