火山喷出物发育土壤的比重及颗粒组成的特征研究

发布时间：2018-01-08 09:12

  本文关键词：火山喷出物发育土壤的比重及颗粒组成的特征研究　出处：《沈阳农业大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 火山灰土 土壤比重 土壤颗粒组成 静水沉降法 筛析法

【摘要】：在对火山喷出物发育土壤进行系统分类时,为了判断是否为火山灰土,需要对土壤样品进行火山灰特性的判定。火山灰特性是一系列性质的集合。在某种条件下,判定土壤是否具有火山灰特性,需要测定其2～0.02 mm粒级的含量。然而,现行火山灰特性的鉴定标准中没有明确规定土壤颗粒组成的测定方法。本研究以东北地区新生代喷发的玄武岩质和粗面岩质火山喷出物发育土壤为研究对象,测定两种岩性土壤小于0.1 mm和小于1 mm两个粒径范围土粒的比重,并进行土壤颗粒组成测定方法的研究与比较,以期为修订和完善火山灰特性的鉴定标准提供科学依据。研究结果表明:(1)玄武岩质火山喷出物发育的土壤,较高发育程度的、粒径小于0.1 mm和粒径小于1 mm 土粒的比重分别为2.78 g cm-3和2.62 g cm-3;低发育程度的、粒径小于0.1 mm和粒径小于1 mm 土粒的比重分别为2.62 gcm-3和2.55 gcm-3。弱发育程度的粗面岩质火山喷出物发育的土壤,粒径小于0.1 mm和粒径小于1 mm 土粒的比重分别为2.56 g cm-3和2.50 g cm-3。同种岩性发育的土壤,粒径小于0.1 mm 土粒的比重较粒径小于1 mm 土粒的比重大。相同粒径范围的土粒,玄武岩质火山喷出物发育土壤的比重较粗面岩质火山喷出物发育土壤的比重大。土壤比重值随着土壤发育程度的加强而增大。(2)静水沉降法测定火山喷出物发育土壤的颗粒组成时,需要实测粒径小于0.1 mm土粒的比重,进而计算各粒级土粒的沉降时间。实验数据统计分析表明:依据斯托克斯定律,在其他条件不变的情况下,比重每增加0.01个单位,较粗颗粒(0.05 mm、0.02 mm)沉降时间缩短1～2 s;黏粒(0.002 mm)缩短约5 min。水温每增加1 ℃沉降时间缩短9～12 min左右。(3)基于粒径小于1 mm土粒比重测定的砂粒、粉粒和黏粒的含量,与基于2.65 gcm-3的比重值测定的各颗粒含量的平均差值分别为17.99gkg-1 15.99gkg-1和14.1gkg-1;基于粒径小于0.1 mm 土粒比重测定的砂粒、粉粒和黏粒的含量,与基于2.65 g cm-3的比重值测定的各颗粒含量的平均差值分别为15.3 g kg-1 13.8 g kg-1和13.2 g kg-1 土壤比重值对土壤各粒级含量的影响程度为:砂粒粉粒黏粒,进而影响土壤质地定名,当土壤比重值改变0.01个单位时,就可能影响质地的命名。(4)基于粒径小于0.1 mm 土粒比重的静水沉降法测定的粒级含量与筛析法测定的同粒级含量相比,大多数土壤样品筛析法比静水沉降法测定的含量偏粗,筛析法和静水沉降法在大粒径(0.5～0.05 mm)的绝对误差含量相对较大,小粒径级(0.05～0.02 mm)的绝对误差含量相对较小。由于不同方法测定的粒级含量存在差距,所以,火山灰特性中需要明确规定土壤颗粒含量的测定方法。
[Abstract]:In order to determine whether the volcanic ash soil is a volcanic ash soil, a systematic classification of volcanic exhalation soil is carried out in order to determine whether it is a volcanic ash soil or not. It is necessary to judge the volcanic ash characteristics of soil samples. The volcanic ash characteristics are a set of properties. Under certain conditions, it is determined whether the soil has volcanic ash characteristics. It is necessary to determine the content of its 2 ~ (2) O ~ (2 +) ~ (2) mm particle size. There is no clear method for determining the composition of soil particles in the current criteria for determining the characteristics of volcanic ash. In this study, basaltic and coarse-surfaced volcanic exhalations from Cenozoic eruptions in Northeast China were studied. The specific gravity of soil particles in the range of less than 0.1 mm and less than 1 mm in two lithologic soils was measured, and the determination methods of soil particle composition were studied and compared. In order to provide scientific basis for revising and perfecting the identification standard of volcanic ash characteristics, the research results show that the soil developed by basaltic volcanic exhalation is of higher development degree. The specific gravity of soil particles with particle size less than 0. 1 mm and less than 1 mm were 2.78g cm-3 and 2.62g cm-3, respectively. Of low development. The specific gravity of soil particles smaller than 0. 1 mm and less than 1 mm were 2.62 gcm-3 and 2.55, respectively. Gcm-3. Soils with a weak degree of development of coarse-faced volcanic eruptions. The specific gravity of soil particle size less than 0. 1 mm and less than 1 mm is 2.56g cm-3 and 2.50g cm ~ (-3), respectively. The specific gravity of soil particles with diameter less than 0.1 mm is larger than that of soil particles with diameter less than 1 mm. The proportion of soil developed by basalt volcanic exhalation is larger than that by coarse-faced volcanic exhalation. The soil specific gravity value increases with the enhancement of soil development degree. The particle composition of the soil developed by volcanic ejection was determined by static water sedimentation method. It is necessary to measure the specific gravity of soil particle size less than 0.1 mm, and then calculate the settlement time of each particle. The statistical analysis of the experimental data shows that: according to Stokes' law, under other conditions unchanged. When the specific gravity increases by 0.01 units, the settling time of the coarse particles is shortened by 1 ~ 2 s than that of the coarse particles by 0.05 mm ~ 0.02 mm. Clay (0.002 mm) is shortened by about 5 mins, and the sedimentation time of water is shortened by 9 ~ 12 min for each increase of water temperature. The sand is measured based on the specific gravity of soil particle size less than 1 mm. The content of powder and clay. The average difference of particle content was 17.99gkg-1 15.99gkg-1 and 14.1gkg-1, respectively, compared with the specific gravity value based on 2.65 gcm-3. The content of sand, silt and clay based on the specific gravity of soil particle less than 0.1 mm. The average difference between the particle content and the specific gravity value based on 2.65 g cm-3 was 15.3 g kg-1 13.8g kg-1 and 13.2 g kg-1, respectively. The influence of soil specific gravity on the content of soil particles is as follows: sand silt clay. Then the soil texture was named, when soil specific gravity changed 0.01 units. For the nomenclature that may affect texture, the particle size content determined by the hydrostatic sedimentation method based on the specific gravity of soil particles less than 0.1 mm is compared with that of the same grain size content determined by the sieve analysis method. Most soil sample sieve analysis method than static water sedimentation method to determine the content of coarse, sieve out method and static water sedimentation method in the large particle size of 0.5 ~ 0.05 mm) the absolute error content is relatively large. The absolute error content of 0.05 ~ 0.02 mm) is relatively small. Because of the difference between different methods, the content of particle size is different. The determination method of soil particle content should be clearly defined in the characteristics of volcanic ash.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S152
，

本文编号：1396487