含硫尾砂充填体长期强度性能及其影响因素

来源期刊:中南大学学报(自然科学版)2018年第6期

论文作者:吴爱祥 姜关照 李红 王贻明 王洪江

文章页码:1504 - 1511

关键词:含硫尾砂;灰砂比;料浆质量分数;强度性能;硫酸盐侵蚀

Key words:sulfur tailings; cement sand ratio; slurry mass fraction; strength property; sulfate attack

摘    要:针对含硫尾砂胶结充填体经常出现的后期强度劣化现象,进行含硫和无硫尾砂充填体强度对比试验,研究灰砂比和料浆对含硫尾砂充填体长期强度性能的影响,并采用XRD和SEM对含硫尾砂充填体中水化产物进行分析。研究结果表明:尾砂含硫量(质量分数)为6.1%,主要硫化物为黄铁矿时,充填体120 d强度下降达到47.4%。灰砂比为1:8时,充填体各龄期强度显著增加,后期强度劣化得到改善。灰砂比为1:16时,充填体长期强度稳定在0.85 MPa左右。充填料浆质量分数对充填体强度影响也较为显著,质量分数为74%~76%时,充填体后期强度下降幅度最小。当充填体内部结构较疏松时,次生石膏可以填充水化产物之间的空隙,在一定程度上改善充填体长期强度性能。充填体结构较为致密时,次生石膏会破坏其微观结构,降低充填体后期强度。

Abstract: Aimed at the common later strength failure phenomenon in cemented sulfur tailings backfill, sulfur and non sulfur tailings backfill strength tests were carried out, and the effect of cement sand ratio and slurry concentration on the cemented sulfur tailings backfill long-term strength property was studied, XRD and SEM were used to analyze the hydration products in sulfur tailings backfill. The results show that the sulfur content of tailings is 6.1%, the main sulfide is pyrite, the 120 d strength of the filling body drops to 47.4%. When the cement sand ratio is 1:8, the strength of the filling body increases significantly at different ages, and the strength degradation at later stage is improved. Cement sand ratio is 1:16, and the long-term strength of the filling body is maintained at about 0.85 MPa. The influence of the filling slurry concentration on the strength of the filling body is also significant. When the concentration is 74%-76%, the decrease of backfill strength is the smallest. The secondary gypsum can fill the voids between the hydration products when the filling structure is loose, which can improve the filling body long-term strength property to some extent. When the filling body structure is dense, the secondary gypsum will destroy its microstructure and reduces the later strength of the filling body.

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