| Sand dune movement is one of the important factors limiting the development of ecological environment,which brings immeasurable losses to human daily production and life.The current traditional sand fixation measures generally have the disadvantages of high cost,poor sustainability and easy to pollute the environment.Therefore,the development of scientific and reasonable sand fixation technology is the focus of wind erosion control.In this paper,we conducted an experimental study on microbial curing of sand barriers to prevent wind erosion based on microbial induced calcium carbonate precipitation(MICP)technology for wind erosion in sandy areas,and designed two curing methods by adding Bacillus pasteurii bacterial solution and different concentrations of cementing solution(1.5mol/L and 2.0 mol/L)to sandy soils to cure the sandy soils into sand barriers and compare their curing effects to determine the microbial We also set different wind speed gradients(6m/s,8 m/s,10 m/s,12 m/s,14 m/s,16 m/s)and different placement intervals(35 cm,40 cm,45 cm)to investigate the wind erosion resistance of the sand barriers at 5 cm,10 cm and 15cm of exposed ground surface,in order to provide new materials and methods for wind and sand control.The main findings are as follows.The main conclusions are as follows:(1)The microbially cured sand barriers prepared by PVC plastic molds were effective,and the dry density of the microbially cured sand barriers increased from 1.61 g/cm~3 of the original sand to 2.43 g/cm~3,and the calcium carbonate content increased from 0.66%to4.47%.(2)The dry density of microbially cured sand barrier was maintained at 1.75～2.15g/cm~3 and the calcium carbonate content ranged from 1.21%to 4.37%when the concentration of cementing solution was 1.5 mol/L.The dry density of microbially cured sand barriers was maintained at 1.85-2.43 g/cm~3 and the calcium carbonate content ranged from 1.44%to 4.47%at 2.0 mol/L.The curing effect of 2.0 mol/L curing solution was better,so 2.0 mol/L curing solution was used to cure sand barriers in this experiment.(3)With the increase of wind speed,the sand-blocking efficiency of microbial curing sand barriers with different deployment specifications showed a gradual decrease.There is a positive correlation between sand transport height and wind speed.In the low wind speed section(6 m/s,8 m/s),the highest sand control efficiency of microbial curing sand barriers with 35 cm,40 cm and 45 cm intervals were 93.71%,95.44%and 94.92%,respectively,and the highest sand transport heights were 42 cm,40 cm and 38 cm,respectively,When the wind speed exceeds 10 m/s,the highest sand control efficiency is 78.76%,82.14%,75.44%,and the highest sand transport height is 62 cm,62 cm,60 cm respectively.(4)The larger the sand barrier interval is,the better the sand barrier with higher height is deployed to prevent wind and sand.The sand barrier interval is 35 cm,and when the wind speed varies from 6 to 12 m/s,the microbial curing sand barrier with a height of 5 cm has the best effect in preventing wind erosion.When the sand barriers were spaced 40 cm apart and the wind speed was set at 6 and 8 m/s,5 cm sand barriers had the best sand control effect,and when the wind speed was set at 10,12,14 and 16 m/s,15 cm sand barriers had the best sand control effect.When the sand barriers are 45 cm apart,15 cm sand barriers have the best sand control effect in the wind speed range of 6-12 m/s.(5)Microbial curing sand barriers can effectively play the role of wind and sand control.For the wind speed range of 7～9 m/s at the southeast edge of Tengger Desert,it is recommended to choose 15 cm height and 45 cm interval microbial curing sand barriers for application. |
PDF Full Text Request