Effects of Three Kinds of Soil Amendments on Shear Strength of Aeolian Soil
Author:
Affiliation:

Clc Number:

Fund Project:

Thousand Youth Talents Plan Project (No.Y472241001)

  • Article
  • |
  • Figures
  • |
  • Metrics
  • |
  • Reference
  • |
  • Related
  • |
  • Cited by
  • |
  • Materials
  • |
  • Comments
    Abstract:

    【Objective】Application of soil amendments to assist desert governance has recently been considered as a promising strategy to improve sand fixing efficiency. However, researches in the past were focused mainly on effects of soil amendments on physicochemical and biological properties of the soil, while this study aimed to reveal those on shear strength of aeolian soils varying in soil water content, in an attempt to provide certain theoretical references for fixing aeolian sands, preventing wind erosion and restoring ecosystems in desert areas. 【Method】In order to explore factors affecting soil mechanics of aeolian soil, soil samples were collected at the edge of the Kumtag Desert for a pot experiment, designed to investigate changes in soil cohesion and internal friction angle via direct shear test. Three kinds of soil amendments were applied, separately into the pots, at set rates, that is, 0.5, 2.0 and 3.5 g•kg-1 for carboxymethylcellulose sodium (CMC); 5, 15 and 25 g•kg-1 for phosphogypsum (PG); and 15, 30 and 45 g•kg-1 for biochar (BC). For each group of treatments, two subgroups different in water content, i.e; 10% and 20%, were also designed. Cotton was planted in each pot and managed in line with the common practice for the crop in the field . At the end of the growth season, soil samples were collected from each pot dried for analysis of cohesion and internal friction angle. Fast shear tests were carried out with a EDJ-1 type direct shear-meter. Four vertical pressures,100, 200, 300 and 400 kPa were applied in the shearing tests, separately. 【Result】Results showed:(1)being the same in soil moisture content, the soil cohesions in the three amended groups were greater than those in the CK group in coherence. Compared with that in CK, cohesion increased by 156.15%~246.18% in Treatments CMC, by 81.06%~229.3% in Treatments PG, and by 71.91%~145.87% in Treatments BC in the subgroup of low water content, and by 126.3%~231.8%, 75.52%~209.9% and 57.79%~124.8%, respectively, in the subgroup of high water content. However, application of soil amendment did not have much effect on soil internal friction angle in aeolian soil.(2)with increasing application rate of soil amendments, soil cohesion significantly increased, showing a positive relationship and good regression between cohesion and soil amendment application rate. (3) being the same in amendment application rate, the soils low in soil water content were higher than their corresponding ones high in soil water content in both cohesion and internal friction angle, but the difference was not significant(P>0.05), and the former was 21.02%, 24.69% and 11.57% higher in Treatments CMC, 10.3%, 19.05% and 13.59% higher in Treatments PG and 16.49%, 9.48% and 16.93% higher in Treatments BC. 【Conclusion】In summary, application of soil amendments can significantly improve soil cohesion, but does not have much effect on soil internal friction angle. In terms of soil coherence enhancing efficiency, the three kinds of soil amendments exhibit an order of carboxymethylcellulose sodium> phosphogypsum> biochar. All the findings in this study demonstrate that low soil water content is more conducive to improvement of shear strength of aeolian soil, by enhancing soil cohesion, together with application of soil amendments, thus stabilizing aeolian soil and improving ecological environment of the desert area. Among the three kinds of soil amendments, CMC is the most effective one.

    Reference
    Related
    Cited by
Get Citation

XI Yinqiao, ZHAO Ying, LI Shengyu. Effects of Three Kinds of Soil Amendments on Shear Strength of Aeolian Soil[J]. Acta Pedologica Sinica,2018,55(6):1401-1410.

Copy
Share
Article Metrics
  • Abstract:
  • PDF:
  • HTML:
  • Cited by:
History
  • Received:November 27,2017
  • Revised:May 20,2018
  • Adopted:August 15,2018
  • Online: August 27,2018
  • Published: