砒砂岩与风沙土复配后的粒度组成变化

Grain size composition change after feldspathic sandstone and aeolian sandy soil compounding

从粒度组成变化情况上探索砒砂岩作为一种固沙新材料的可能性,可为毛乌素沙化治理、保持水土、发展农业种植提供科学支撑。将砒砂岩与风沙土分别按1∶0、1∶1、1∶2、1∶5和0∶1质量比复配,用激光粒度分析仪对其粒度组成及级配特性进行分析研究。结果表明:砒砂岩与风沙土复配后,改变了风沙土以砂粒为主、结构松散、易风蚀的特点,随着砒砂岩质量的增加,<0.05 mm粒径的质量分数增加,质地呈现砂土-砂壤-壤土-粉壤的转变;且风沙土的粒度分布范围小、均质性强等特点得到一定程度改善,砒砂岩与风沙土复配后,其粒度分布范围变广,当砒砂岩与风沙土复配的质量比为1∶5(不均匀系数为54.71,曲率系数为2.54)或1∶2(不均匀系数为76.21,曲率系数为1.12)时,其颗粒级配连续,且级配特性良好。因此,从粒度组成上看,砒砂岩具有固沙的可能,质地条件随砒砂岩质量的增加而变好,级配特性以砒砂岩∶风沙土按1∶2或1∶5质量比进行复配为宜。

The purpose of this research was to explore the possibility of feldspathic sandstone as a kind of new sand-fixing material from the grain size composition change statistics and particle size distribution charactertistics,to provide a scientific support for desertification control,soil and water conservation and development of farming in Mu Us Sandy Land,and at the same time,to improve the living standards of local people. Methods of mixing feldspathic sandstone and aeolian sandy soil according to the kinds of mass ratios of mf∶ ms= 1∶ 0,1∶ 1,1∶ 2,1∶ 5,and 0∶ 1（ where mfis the quality of the feldspathic sandstone,msis the quality of the aeolian sandy soil） were used,then,the particle graded composition and particle size distribution characteristics of feldspathic sandstone and aeolian sandy soil compound soil were studied with Malvern 2000 laser particle size analyzer. The results showed that after feldspathic sandstone and aeolian sandy soil compounding,the texture characteristics of compound soil changed for the better.These features of sand-based,loose structure,easy to wind erosion of aeolian sandy soil were improved gradually after feldspathic sandstone and aeolian sandy soil compounding. The mass content of 〉0. 05 mm particle increased with feldspathic sandstone mass increasing and the mass content of 〈0. 05 mm particle decreased with feldspathic sandstone mass increasing. The texture presented this kind of changetrend from sand to sandy loam to loam to silt loam. The small particle size distribution,good particle homogeneity and other shortcoming of aeolian sandy soil were improved to a certain degree,and the particle size distribution became broad after feldspathic sandstone and aeolian sandy soil compounding.The grain grading was continuous and the particle grading characteristics were good when the mass ratio of feldspathic sandstone and aeolian sandy soil compound soil was 1∶ 5（ the nonuniform coefficient was 54. 71 and the curvature coefficient was 2. 54） or 1 ∶ 2（ the nonuniform coefficient was 76. 21,the curvature coefficient was 1. 12）. After feldspathic sandstone and aeolian sandy soil compounding,not only the shortcoming of particle size composition of aeolian sandy soil was improved,but also this problem of high clay content of feldspathic sandstone was resolved,which effectively prevented the soil compaction problem of feldspathic sandstone. After feldspathic sandstone and aeolian sandy soil compounding,and particles of various sizes were mixed,the grain grading was continuous from microscopic particles of view,which provided a scientific base for land desertification control. Consequently,feldspathic sandstone has the possibility of sand-fixing from grain size composition of view. The texture characteristics changes for better with feldspathic sandstone mass increasing,and when the mass ratio of feldspathic sandstone and aeolian sandy soil is 1∶ 2 or 1∶ 5 which compound better for particle grading characteristics.