掺钢渣土强度的干湿循环劣化效应及机理研究

Mechanism of Alteration in Mechanical Property of Soil Mixed with Steel Slag Affected by Dry-Wet Cycles

以掺钢渣土为主要研究对象,采用"透水石上吸水-自然风干"方法模拟路床材料的干湿循环状态,研究了掺钢渣土强度的干湿循环劣化性能,从强度破坏模式与微观机理分析石灰对钢渣活性激发的影响。结果表明:随着干湿循环次数的增加,试件含水率呈增大趋势并趋于稳定,变化幅度在3%以内。掺钢渣土无侧限抗压强度与劈裂强度的干湿循环劣化效果明显,其中石灰土的衰减幅度最大,分别为59.5%与55.3%,石灰钢渣土最小。劈裂抗拉强度与无侧限抗压强度比值结果发现,石灰土与石灰钢渣土随干湿循环次数变化,该比值f_t/f_(cu)基本稳定,在12.3~19.4之间,但钢渣土f_t/f_(cu)均小于12.8;钢渣土劈裂抗拉强度衰减幅度显著高于无侧限抗压强度,劈裂抗拉强度更能反映钢渣土的干湿循环劣化性能。干湿循环后掺钢渣土试件抗压强度与试件核心区的干湿循环劣化程度密切相关,而劈裂强度则更多的反映试件外围部分的强度特征。对比钢渣土与石灰钢渣土强度形成机理,验证钢渣在碱性环境中更易形成强度大的沸石类矿物。在工程应用中,建议掺入适量石灰。

The soil mixed with steel slag is taken as study object, the ＂absorbing water from permeable stone and drying naturally＂ method is used to simulate the dry-wet cycle of embankment materials. The strength deterioration performance after wetting and drying cycles is studied for the soil mixed with steel slag. , and the impact of lime on activation of steel slag is analyzed from the strength failure mode and micro mechanism. The results show that with the increase of the number of wetting and drying cycles, the water content of the specimen increases and tends to be stable, the variation range within 3%. The effects of the drying-wetting cycles on unconfined compressive strength and splitting strength are obvious, the biggest attenuation amplitude is for the lime soil which are respectively 59.5% f and 55.3%, and the soil mixed with lime and steel slag is the least. Splitting tensile strength and unconfined compressive strength ratio for lime soil and lime stabilized soil with wetting and drying cycles ft/fcu is between 12.3-19.4, but the ft/fcu for soil mixed with steel slag is less than 12.8. Splitting tensile strength of Soil mixed with steel slag is significantly higher than that of unconfined compression strength, which can reflect the dry wet cycle deterioration performance. The compressive strength has close relations with deterioration degree of the core zone, and tensile strength can reflect outer parts of the strength characteristics more. The appropriate amount of lime is recommended to be added in practical applications.