LI Chi, WANG Shuo, WANG Yan-xing, et al. Field experimental study on stability of bio-mineralization crust in the desert[J]. 2019, 40(4): 1291-1298.DOI: 10.16285/j.rsm.2018.0677.
Field experimental study on stability of bio-mineralization crust in the desert
Microbial induced calcite precipitation(MICP) technology is applied to the formation of in-situ bio-mineralization crust on the surface of desert
which enables floating dune to be semi-fixed and fixed
hinders wind erosion
and fundamentally blocks the source of sandstorm. Two bio-mineralization test plots(TP1 and TP3) were built using two different microbial strains on the Aeolian sand sur
face in Ulan Buh desert
Inner Mongolia Autonomous Region of China. The field-scale experiment methods and processes were designed to evaluate and analyze the strength of bio-mineralization crust and its long-term stability in the desert environment. Staphylococcus
extracted from local Aeolian sand
and Sporoscarcina pasteurii
a traditional bio-mineralized bacterium
were used to induce the formation of calcium carbonate crystals. Through penetration tests in site
the penetration resistance developed along the depth of bio-mineralization crust was recorded on the 7
th
14
th
28
th
60
th
and 210 th day. The strength of bio-mineralization crust was converted according to the value of average penetration resistance at 2.0 cm of the crust. The variation of strength of bio-mineralization crust with mineralization time was summarized. From visual observation in site
the bio-mineralization crust began to form on the 4
th
day. The average thickness ranges from 2.0 cm to 2.5 cm on the 7
th
day
and the strength of bio-mineralization crust induced from Staphylococcus was 1.05 times than that of Sporoscarcina pasteurii. For the bio-mineralization crust TP3 induced from Sporoscarcina pasteurii after freeze-thaw cycles on the 210 th day
the average thickness decreased from 0.7 cm to 1.0 cm
the strength was reduced by 19% and the content of calcium carbonate was reduced by 15%-30% compared with that on the 7
th
day. However
the strength of bio-mineralization crust TP1 induced from Staphylococcus on the 210
th
day was reduced only by 2%
which is a little less than that on the 7
th
day. MICP technology can be applied to the formation of in situ bio-mineralization crust in desert. The bio-mineralization crust developed from Staphylococcus has better strength performance and long-term stability in desert environment than that from Sporoscarcina pasteurii.