干湿循环作用下掺铁尾矿砂水泥土耐久性研究

Study on the Durability of Iron-doped Tailings Cement Soil Under Dry-wet Cycle

为了探究掺铁尾矿砂水泥土在特殊环境条件下的耐久性,对掺铁尾矿砂水泥土进行了干湿循环试验,并与相同条件下素水泥土进行了对比。通过干湿循环试验研究发现,高掺量水泥强度损失较低。铁尾矿砂的掺入会延缓水泥土受干湿循环次数增加所产生的强度损失,但随着干湿循环次数增加其强度损失与素水泥土逐渐接近,干湿循环导致的铁尾矿砂水泥土强度降低主要表现在黏聚力大幅下降,内摩擦角变化较小。利用极限偏应力(σ_(1)-σ_(3))_(max)、c,φ值与孔隙率η、胶结物体积含量Gv等参数的关系,建立了干湿循环循环作用下铁尾矿砂水泥土强度损伤模型,通过计算值与试验值对比,该损伤模型可以有效地预测铁尾矿砂水泥土在干湿循环下的极限偏应力(σ_(1)-σ_(3))_(max)及c,φ值。

In order to explore the durability of iron-doped tailings cement soil under complex environmental conditions,the dry-wet cycle test of iron-doped tailings cement soil was carried out,and compared with plain cement soil under the same conditions.The dry and wet cycle test found that the strength loss of high-content cement is low.The incorporation of iron tailings sand will delay the strength loss caused by the increase of the number of dry and wet cycles of cement soil,but with the increase of the number of dry and wet cycles,its strength loss gradually approaches that of solid cement soil,and the decrease in the strength of iron tailings cement soil caused by dry and wet cycles is mainly reflected in the large decrease in cohesion and small change in internal friction angle.Using the relationship between ultimate deflection stress(σ_(1)-σ_(3))_(max),c,φvalue and porosityη,cementite volume content G v and other parameters,the strength damage model of iron tailings cement soil under the action of dry and wet cycle and freeze-thaw cycle was established,and the damage model can effectively predict the ultimate deflection stress(σ_(1)-σ_(3))_(max) and c,φvalue of iron tailings cement soil under dry and wet cycle by comparing the calculated value with the experimental value.