| 摘要: |
| 【目的】研制具有较强透水性、保水性和较高强度的棉秆纤维轻量土，为海绵城市建设提供支持。【方法】采用正交试验设计，将棉秆纤维含量、EPS颗粒含量、水泥含量、砂含量4个因素作为棉秆纤维轻量土的影响因素，每个因素取5个水平，通过L25（54）正交试验，研究棉秆纤维轻量土在不同配合条件下的强度特性、渗透特性和密度特性，并分析棉秆纤维、EPS颗粒、水泥和砂含量对棉秆纤维轻量土性能的影响。【结果】当棉秆纤维含量、水泥含量、砂含量和EPS颗粒含量分别为4，25，120和12 g/kg时，所得棉秆纤维轻量土满足地基承载力要求且透水性能最好，其抗压强度为114.59 kPa，渗透系数为6.84×10-5 cm/s。棉秆纤维含量、EPS颗粒含量、水泥含量、砂含量4个因素对棉秆纤维轻量土抗压强度影响的权重依次为5.94%，16.91%，68.33%和8.82%，对渗透系数影响的大小顺序为水泥含量＞EPS颗粒含量＞砂含量＞棉秆纤维含量，对密度影响的大小顺序为EPS颗粒含量＞砂含量＞水泥含量＞棉秆纤维含量。棉秆纤维轻量土无侧限抗压强度与EPS颗粒含量呈负相关，与水泥含量呈正相关；棉秆纤维轻量土密度与EPS颗粒含量和砂含量呈幂函数相关。增加20~40 g/kg的水泥含量可使棉秆纤维轻量土渗透系数下降10~1 000倍，添加4 g/kg的棉秆纤维含量使轻量土的饱和含水率较原状黄土增大2%~4%，即可有效提高轻量土的持水性能。【结论】将4 g/kg棉秆纤维含量、25g/kg水泥含量、120 g/kg砂含量和12 g/kg EPS颗粒含量混合，可以配制出适合海绵城市建设的棉秆纤维轻量土。 |
| 关键词: 海绵城市 轻量土 棉秆纤维 抗压强度 渗透特性 |
| DOI： |
| 分类号: |
| 基金项目:陕西省重点研发计划项目（2017ZDXM-SF-074）；陕西省教育厅2018年度专项科学研究计划项目（18JK0247） |
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| Mixing ratio of lightweight soil with cotton stalk fibers |
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YANG Tao,ZHANG Aijun,MI Wenjing,et al
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| Abstract: |
| 【Objective】This study prepared lightweight soil with strong water permeability,water retention and high strength to support the construction of sponge city.【Method】Using orthogonal test design,four factors of cotton stalk fibers,EPS,cement and sand were analyzed.Each factor had 5 levels.Through L25 (54) orthogonal tests,the strength,permeability and density of lightweight soil with cotton stalk fibers under different mixing conditions were studied,and the effects of cotton stalk fiber,EPS granule,cement and sand on the performance of lightweight soil were analyzed.【Result】When the cotton stalk fiber,cement,sand and EPS content were 4,25,120 and 12 g/kg,the lightweight soil with cotton stalk fibers met the requirement of foundation bearing capacity and had the best water permeability.The compressive strength was 114.59 kPa and the permeability coefficient was 6.84×10-5 cm/s.The weights of cotton stalk fiber,EPS granule,cement and sand on compressive strength of lightweight soil with cotton stalk fibers were 5.94%,16.91%,68.33% and 8.82%,respectively.The order of influence on permeability coefficient was cement>EPS>sand>cotton stalk fiber,while on density was EPS>sand>cement>cotton stalk fiber.The unconfined compressive strength of lightweight soil was negatively correlated with the amount of EPS particles,and positively correlated with the amount of cement.The density of lightweight soil was related to the amount of EPS particles and the amount of cement.Increasing the cement content by 20-40 g/kg can reduce the permeability coefficient of lightweight soil by 10-1 000 times.Adding 4 g/kg cotton stalk fiber can increase the saturated water content of lightweight soil by 2%-4% compared with undisturbed loess,indicating that the water holding capacity of the lightweight soil can be improved effectively.【Conclusion】Lightweight soil with cotton stalk fibers suitable for sponge city construction can be formulated by mixing 4 g/kg cotton stalk fiber,25 g/kg cement,120 g/kg sand and 12 g/kg EPS. |
| Key words: sponge city lightweight soil cotton stalk fiber compressive strength permeability |
