A study of the engineering characteristics of reinforced loose sand by modified nano-Si materials
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摘要: 为了改变松散砂土的低强度和低抗侵蚀性，本文以纳米硅材料为基础，采用聚丙烯酰胺类作为改性剂，对松散砂土进行加固研究。分别研究在不同浓度的纳米硅材料以及不同掺量的改性剂的共同作用下，加固松散砂土的无侧限抗压强度、抗剪强度以及其崩解特性的变化规律，并对其加固机理进行分析。试验结果表明，改性后的纳米硅材料对松散砂土的无侧限抗压强度、抗剪强度以及抗崩解能力都得到较大的提高。当纳米硅材料浓度一定时，砂土的抗压强度和抗剪强度随着改性剂掺量的增加出现先增大后减小的趋势；在纳米硅浓度20%、改性剂掺量0.2%时抗压强度达到最大值970 kPa；在纳米硅浓度20%，改性剂掺量0.3%时黏聚力和摩擦角分别为173.2 kPa和39.3°；在加固松散砂土的抗崩解试验中，当纳米硅浓度大于20%、改性剂掺量大于0.1%时，加固后的砂土在水中侵泡8 d后砂样的崩解率低于50%；当纳米硅浓度20%，改性剂掺量0.2%时，加固砂土不崩解。综合试验结果，建议纳米硅溶液的浓度在20%，改性剂的掺量为0.2%作为改性纳米硅材料加固松散砂土的最优配比。Abstract: In order to change the low strength and low erosion resistance of loose sand, the reinforcement of loose sand is exaimed in this paper, which is based on nano-silicon material and takes polyacrylamide as modifier. Under the joint action of different concentrations of nano-silicon material and different amount of modifier, the unconfined compressive strength, shear strength and disintegration characteristics of the the consolidated loose sand are studied respectively, and the reinforcement mechanism is analyzed. The experimental results show that the unconfined compressive strength, shear strength and anti-disintegration ability of the modified nano-silica material are greatly improved. When the concentration of nano-silicon is constant, the compressive strength and shear strength of sand increase at first and then decrease with the increasing modifier content. When the concentration of nano-silicon is 20% and the amount of modifier is 0.2%, the compressive strength reaches the maximum 970 kPa. When the concentration of nano-silicon is 20% and the amount of modifier is 0.3%, the adhesion force and friction angle are 173.2 kPa and 39.3 °, respectively. In the anti-disintegration test of the consolidated loose sand, when the concentration of nano-silicon is more than 20% and the amount of modifier is more than 0.1%, the disintegration rate of the reinforced sand sample is less than 50% after 8 days of invading in water. When the concentration of nano-silicon is 20% and the amount of modifier is 0.2%, the stabilized sand will not disintegrate. Comprehensive test results suggest that the concentration of nano-silicon solution of 20% and the amount of modifier of 0.2% are the best proportions of the modified nano-silicon material to strengthen loose sand.
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Key words:
- nano-silicon /
- modifier /
- sand /
- reinforcement /
- disintegration characteristics
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