铁矿尾砂配施有机物料对褐土压缩及回弹特性的影响

Effects of Iron Tailings Combined with Organic Materials on Compression and Rebound Characteristics of Cinnamon Soil

摘要:

为探讨铁矿尾砂配施有机物料对褐土压缩-回弹特性的影响，将混有铁矿尾砂和有机物料的土壤以18%含水率培养一昼夜，按1.25g/cm³容重装入土工试验专用环刀，采用快速固结试验方法，进行单轴压缩试验。结果表明：随铁矿尾砂施用量增加，在低应力时，土壤孔隙比减小量(∆e)变大；在高应力时，土壤△e变小。预固结压力值(P_c)和压缩指数(C_c)均随铁矿尾砂施用量增加而降低，P_c和C_c变化范围分别为72.91~119.30kPa、0.445~0.720，二者均与有机质含量呈极显著正相关关系(P<0.01)，与砂粒含量呈极显著负相关关系(P<0.01)。回弹指数(C_s)变化范围为0.0109~0.0169，与有机质及砂粒含量均无显著相关关系，有机物料是影响土壤C_s的主要因素。与对照相比，200g/kg铁矿尾砂配施有机物料处理使C_s降低12.77%，P_c和C_s分别提高6.93%和22.14%，降低压实风险。

Abstract:

This study is to explore the effects of iron tailings combined with organic materials on the compression and rebound characteristics of cinnamon soil. Cinnamon soil mixed with iron tailings and organic materials was cultivated for 24 h at 18% moisture content and loaded into the special ring knife for geotechnical test according to the bulk density of 1.25 g/cm³, then the uniaxial compression test was conducted by using the rapid consolidation method. The results show that with the increase of iron tailings application, soil void ratio reduction (△e) is increased at low applied stresses and reduced at high applied stresses. Both the pre-consolidation stress (P_c) and the compression index (C_c) are decreased with the increase of iron tailings application, and they vary between 72.91-119.30 kPa and 0.445-0.720, respectively. P_c and C_c are significantly positively correlated with organic matter content (P<0.01) and significantly negatively correlated with sand content (P<0.01). Organic material is the main factor affecting soil rebound characteristics. The rebound index (C_s) varies from 0.010 9 to 0.016 9, no significant correlation is found with the organic matter and sand contents. Compared with the control, the treatment of 200 g/kg iron tailings combined with organic materials can reduce soil C_s by 12.77% and increase P_c and C_s by 6.93% and 22.14% respectively, thus can remarkably reduce the compaction risk.