Design of lightweight soil mixture ratio of cotton stalk fiber EPS particles
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摘要: 为满足湿陷性黄土地区海绵城市道路建设需求,研制了一种具有轻质、高强并兼具一定渗透性的棉秆纤维EPS颗粒轻量土作为路基换填材料。该轻量土由棉秆纤维、聚苯乙烯(EPS)颗粒、水泥、黄土和水混合而成。通过室内试验对不同棉秆纤维掺量及长度、不同EPS颗粒掺量及粒径、不同水泥掺量轻量土的密度、强度、变形和渗透性进行研究,进而设计棉秆纤维EPS颗粒轻量土配合比。结果表明:轻量土各成分中,EPS掺量和水泥掺量对轻量土密度的影响最大;水泥掺量与轻量土强度之间为正相关关系,与渗透系数之间为负相关关系;EPS掺量和粒径与轻量土强度之间为负相关关系,与渗透系数之间为正相关关系;棉秆纤维的加入改善了轻量土的塑性性能,并使轻量土的渗透性有一定程度的提高。各因素对轻量土强度影响的大小顺序为:水泥掺量>EPS掺量和粒径>棉秆纤维掺量和长度。满足湿陷性黄土地区海绵城市道路建设需求的棉秆纤维EPS颗粒轻量土最优配合比为:黄土∶棉秆纤维(长度9 mm)∶EPS颗粒(粒径0.5~1.0 mm)∶水泥∶水=1000∶4∶18∶35∶400。Abstract: To satisfy the demand of spongy city road construction in collapsible loess areas, a kind of cotton stalk fiber EPS particle light soil with light weight, high strength, and certain permeability was developed as a roadbed replacement material. This lightweight soil is a mixture of cotton straw fibers, polystyrene (EPS) granules, cement, loess, and water. In the present study, the density, strength, deformation and permeability of lightweight soil with different cotton stalk fiber contents and lengths, different EPS particle contents and particle sizes, and different cement contents were tested by a series of geotechnical tests. The mixture ratio of cotton stalk fiber EPS particle lightweight soil was designed. The results show that among the various components of lightweight soil, the content of EPS and cement content have the most significant effect on the density. Besides, there is a positive correlation between cement content and strength, and a negative correlation with the permeability coefficient. The EPS content and particle size are negatively correlated with the strength of the lightweight soil, and positively correlated with the permeability coefficient; the addition of cotton stalk fiber improves the plasticity of the lightweight soil and improves the permeability of lightweight soil to a certain extent. The order of magnitude of the effect of various factors on the strength of lightweight soil is: cement content>EPS content and particle size>cotton stalk fiber content and length. The optimal mix ratio of lightweight soil to satisfy the demand of spongy city road construction in collapsible loess areas is: loess soil∶cotton stalk fiber (length 9 mm)∶EPS particles (particle size 0.5-1.0 mm)∶cement∶water = 1,000∶4∶18∶35∶400.
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表 1 轻量土各成分掺量及规格
Table 1. The mixture ratio and specifications of lightweight soil
因素 掺量/(g·kg−1) 粒径/长度/mm 棉秆纤维 0、2、4、6 5、9、13、17 EPS颗粒 12、15、18 0.5~1.0、1.0~2.0、2.0~4.0 水泥 25、30、35 水 400 - -
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