微生物矿化技术改良砒砂岩风化土的冻融特性试验研究  

Experimental Study on Freeze-Thaw Characteristics of Weathered Arsenic Sandstone Soil Improved by Microbial-Induced Calcium Precipitation

作　　者：王燕星 高瑜[2] 杨国辉[2] 牛恒茂 刘斌[1] 任雪丹 WANG Yanxing;GAO Yu;YANG Guohui;NIU Hengmao;LIU Bin;REN Xuedan(Secondary School of Architectural Engineering and Surveying,Inner Mongolia Construction Vocational and Technical College,Hohhot 010051,China;College of Civil Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)

机构地区：[1]内蒙古建筑职业技术学院建筑工程与测绘二级学院,呼和浩特010051 [2]内蒙古工业大学土木工程学院,呼和浩特010051

出　　处：《工业建筑》2024年第9期10-18,共9页Industrial Construction

基　　金：内蒙古自治区基本科研业务费研究项目(基于微生物诱导矿化技术的建筑垃圾再生绿色材料技术研究);内蒙古工业大学科学研究项目(2021074)。

摘　　要：砒砂岩地区严重的水土流失使当地植被稀少、生态环境恶劣,同时砒砂岩岩体经风化后形成的碎屑不断迁移到黄河等河流中,成为黄河中上游粗泥沙的主要来源。为此,将微生物矿化技术应用于砒砂岩及其风化土的加固和改良解决其遇水溃散的难题。在实现砒砂岩风化土矿化加固的基础上,采用宏观力学性能测试结合孔隙测定微细观结构测试手段,研究冻融循环作用后矿化风化土的性能变化和衰退机理。结果表明:矿化试样经盐蚀冻融循环后,其强度降低,内部孔隙不断变化,不同大小的孔径发育或相互转化。盐环境对试样强度性质造成的削弱程度大于去离子水中试样的劣化程度,复合盐环境中试样强度性质的削弱大于单一盐环境中的试样。混合盐环境下经历5次冻融循环后试样就侵蚀破坏了,抗冻融能力降低至0.125 6,同时期去离子水环境中试样抗冻融能力降低至0.416 7,相差将近3倍;因冻胀作用、干湿作用和颗粒间连接的破坏,试样孔隙度增大,不同类型孔的分布量累积变化率随冻融循环次数的增加而增大。试样强度的降低,实际是内部骨架力学性能降低的宏观体现,试样内部孔隙骨架因抵抗冻胀力能力的不断减弱,造成宏观上强度的不断降低,随着试样抵抗变形潜能的释放,冰的体积膨胀系数和孔隙收缩系数不断变大,混合盐由于内部胶结破坏多而孔隙骨架的变形能力弱,膨胀系数最大,收缩系数最小。Severe soil erosion in arsenic sandstone areas not only reduces the local vegetation and deteriorates the ecological environment,but also the debris formed by weathered arsenic sandstone constantly migrates into the Yellow River and other rivers,becoming the main source of coarse sediment in the middle and upper reaches of the Yellow River.Therefore,the microbial-induced calcium precipitation technique was applied to arsenic sandstone and its weathered soil to cure and improve their water disintegration.On the basis of the mineralization and cementation for weathered soil of arsenic sandstone,macroscopic mechanical properties tests combined with microstructural tests of pore sizes were conducted to study the property changes and deteriorative mechanisms of the weathered soil after freeze-thaw cycles in the salt corrosion environment.The test results indicated that the strength of the soil-mineralized specimens decreased after freeze-thaw cycles in the salt corrosion environment,and the internal pores changed continuously with different sizes of pores developing or transforming into each other.The attenuation in the intensity properties of soil-mineralized specimens in the salt corrosion environment was greater than that in the deionized water environment,and the attenuation in the intensity properties of soil-mineralized specimens in the composite salt environment was greater than that in the single salt environment.After five rounds of freeze-thaw cycles in the mixed salt environment,the soil-mineralized specimens were damaged and the freeze-thaw resistance was reduced to 0.1256,and simultaneously,the freeze-thaw resistance of the soil-mineralized specimens in the deionized water environment was reduced to 0.4167 in the same period,a difference was nearly three times;the porosity of the soil-mineralized specimens increased as a result of the frost heave action,wet-dry action and the destruction of inter-particle connections,and the cumulative ratio of change in different types of pores increased with the round o

关 键 词：微生物诱导矿化技术 砒砂岩 风化土 冻融循环 核磁共振 

分 类 号：TU41[建筑科学—岩土工程]