摘要
【目的】研究微生物诱导碳酸钙沉淀技术(Microbially induced calcium carbonate precipitation,MICP)对红黏土物理性质及红黏土边坡稳定性的影响。【方法】采用三轴固结不排水剪切试验、变水头渗透试验比较微生物改良前后的红黏土抗剪强度和渗透性变化,用ABAQUS有限元软件模拟降雨作用下不同改良深度红黏土边坡的稳定性。【结果】微生物改良红黏土有效内摩擦角提高了18.73%,有效黏聚力提高了116.47%,渗透系数降低两个数量级。有限元结果表明,用微生物对红黏土边坡进行改良防护,边坡的位移得到较好的限制,随着改良深度的加深,对位移限制作用逐渐减弱,但改良深度穿过边坡滑移面时又会提高位移限制效果。微生物改良对边坡水平位移的约束效果要优于对竖向位移的约束效果。边坡塑性区的分布随改良深度的加深逐渐往边坡内部转移。对红黏土边坡浅层土的改良显著提高了边坡安全系数,随着改良区域的加深,边坡安全系数增幅减小。改良深度到达5 m时,改良区域穿过了边坡的滑动面,此时边坡的最大总位移减小93.66%,最大塑性应变减小98.46%,安全系数由1.07增至1.46,边坡到达一个十分稳固的状态。【结论】研究确定了MICP土体加固技术应用在红黏土边坡防护是可行的,确定了当改良区域穿过边坡滑动面时边坡的安全性能满足要求,相对于土体整体改良降低了防护成本,为生态边坡防护提供了一种新的思路和相关理论参考。
【Objective】The objective of this article was to investigate the effect of microbially induced calcium carbonate precipitation(MICP)on the physical properties of red clay soils and the stability of red clay slopes.【Method】The triaxial consolidation undrained shear test and variable head infiltration test were used to compare the changes in the shear strength and permeability of the red clay soil before and after microbial improvement,and the ABAQUS finite element software was used to simulate the stability of red clay slopes with different improvement depths under the action of rainfall.【Result】The effective internal friction angle of the microbially modified red clay increased by 18.73%,the effective cohesion increased by 116.47%,and the permeability coefficient decreased by two orders of magnitude.The finite element results showed that the displacement of the slope was better limited by improving the protection of the red clay slope with microorganisms,and the effect of displacement limitation gradually decreased with the depth of improvement,but the effect of displacement limitation was improved again when the improvement depth crossed the slope slip surface.The restraining effect of microbial improvement on the horizontal displacement of the slope was better than the restraining effect on vertical displacement.The distribution of the plastic zone of the slope gradually shifted to the inner part of the slope as the depth of improvement increased.The improvement of the shallow layer of red clay slopes significantly improved the slope safety factor,and the increase in the slope safety factor decreased as the improvement area deepened.When the improvement depth reached 5 meters,the improvement area crossed the sliding surface of the slope.At this time,the maximum total displacement of the slope was reduced by 93.66%,the maximum plastic strain was reduced by 98.46%,the safety factor was increased from 1.07 to 1.46,and the slope reached a very stable state.【Conclusion】The study has proved that MICP s
作者
周磊
易文
江伟健
金丽萍
杨为环
ZHOU Lei;YI Wen;JIANG Weijian;JIN Liping;YANG Weihuan(School of Civil Engineering,Central South University of Forestry&Technology,Changsha 410004,Hunan,China;School of Design and Art,Hunan University of Technology and Business,Changsha 410205,Hunan,China;Zhejiang Runcheng Environmental Protection Group Co.Ltd.,Hangzhou 311500,Zhejiang,China)
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2023年第7期179-188,共10页
Journal of Central South University of Forestry & Technology
基金
国家林业局948项目(2015-4-38)
湖南省交通科技计划项目(202212)。
关键词
微生物改良土
边坡生态防护
边坡稳定性分析
强度折减法
红黏土
microbially improved soil
slope ecological protection
slope stability analysis
strength reduction method
red clay
