微生物砂浆防护粉土坡面的强度与抗侵蚀性影响因素分析  

Influence factor analysis related to strength and anti-erosion stability of silt slope with microbial mortar protective covering

作　　者：邵光辉[1,2] 冯建挺 赵志峰[1,2] 刘鹏[1,2] 李泽[1] 周宁娜[1] 

机构地区：[1]南京林业大学土木工程学院,南京210037 [2]江苏省水土保持与生态修复重点实验室,南京210037

出　　处：《农业工程学报》2017年第11期133-139,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51578293);江苏高校优势学科建设工程资助项目(PAPD2015);国家大学生实践创新训练计划项目(201510298005Z)

摘　　要：微生物砂浆表面防护处理是处理粉土边坡扬尘与水流侵蚀问题的新技术。采用微生物砂浆层对粉土表面进行防护处理试验,通过微型贯入试验、水稳定性试验以及模拟降雨冲刷试验,分析了微生物砂浆防护层厚度、CaCl_2和尿素混合胶结溶液浓度、喷洒处理遍数等参数变化对微生物砂浆表面防护层的强度、水稳定性和土壤剥蚀率等性能的影响规律。结果表明,微型贯入仪可用于微生物砂浆表面防护层的强度测定,防护层的强度、水稳定性随胶结溶液浓度和喷洒处理遍数的增长而提高,最小有效厚度为5 mm。采用浓度为0.50 mol/L胶结溶液喷洒4遍,厚5 mm的防护层能够达到贯入阻力310 kPa,防护强度比77.5,崩解率2.3%,浸水强度损失率5.4%,具备较高的强度和较好的抗崩解性与强度水稳定性。粉土边坡在微生物砂浆防护前后,土壤剥蚀率能够从大于29.6降至6.8 g/(m^2·s)以下。该研究表明,微生物砂浆层用于粉土表面防护具有较好的抗冲刷性;微生物诱导结晶的方解石形成包裹砂颗粒的胶结微结构,能够使表面防护砂浆层具备良好的抗水流侵蚀性。Microbial mortar protective covering is a new technology for controlling silt slope surface dust and water erosion.The anti-erosion performance of the protective covering depends to a large extent on the strength and stability of covering.However,the factors that govern the protective property of covering have not been fully studied.Based on microbial induced calcite precipitation（MICP） technology,the surface protective covering experiments were carried out to treat silt slope surface against rainfall erosion.Indoor model tests on silt surface protective covering by microbial mortar were performed to investigate the properties such as strength,water stability and anti-erosion.Sand was covered on dredger fill silt surface to form a thin layer,and then some Sporosarcina pasteurii and a kind of cementing solution containing a mixture of CaCl_2 and urea were sprayed on the sand layer surface to obtain a crustose protective covering.The micro-penetration test was adopted to investigate the penetration resistances change of uncovered silt and protected silt covered with microbial mortar crust.The property of protective strength ratio measured by micro-penetration test was used to evaluate the strength of microbial mortar protective covering relative to uncovered silt surface.The collapse ratio and strength loss ratio were tested on the microbial mortar protective covering by immersed in water for 12 h to assess its water stability performance.The change laws of protective covering strength and water stability were drawn from different covering thickness,mixed cementing solution concentration of CaCl_2 and urea,and spraying times.On the basis of the tests of protective covering,the rainfall model experiments were conducted.A slope angle variable steel tank with the size of 1.4 m×0.3 m×0.06 m（length×width×height） was applied for holding test material and simulating the silt slope,which was subjected to strong rainfall scour under a rainfall simulating system.The soil detachment rates were investigated from th

关 键 词：粉土 侵蚀 砂浆 诱导碳酸钙沉积 水稳定性 土壤剥蚀率 防护工程 

分 类 号：S157.1[农业科学—土壤学]