摘要
以河南安阳典型弱膨胀土为研究对象,分别对素土及离子土固化剂(Ionic Soil Stabilizer,简称ISS)改良土进行一系列的理化试验研究,通过标准吸湿含水率试验分析土体吸湿持水能力的变化;通过X射线衍射、傅立叶红外光谱测试、阳离子交换量及可交换阳离子成分测定、Zeta电位、比表面积,扫描电镜试验分析土体矿物组分、晶体结构、电化学性质及表面属性等反映土体胀缩本质因素的变化规律。试验结果表明:膨胀土经离子土固化剂处理后,吸湿持水能力下降,膨胀能力变弱,土样矿物成分未发生明显变化,但蒙脱石类矿物d001晶层间距变小,层间水合度降低;通过离子交换,ISS置换出膨胀土体颗粒表面亲水性阳离子,促使土体阳离子交换量减小,可交换阳离子主要成分为Ca2+;改良土体ξ电位降低,土颗粒间连接力增强,比表面积减少。ISS改良机理可解释为通过离子交换,吸附,包裹等一系列复杂的表面物化反应,降低黏土矿物晶层间"水敏性",改变土颗粒表面的双电层结构,促使结合水膜厚度减薄,从而降低了土体的膨胀性,水稳定性。
A series of experiments are conducted to analyze the physicochemical properties of the typical weak expansive soil of Anyang before and after treated by ionic soil stabilizer（ISS）.Standard moisture absorption content test is used to analyze the water-holding capacity of soil.XRD and FITR tests are employed to identify mineral component and crystal structure,cation exchange capacity and exchangeable cation composition.Zeta potential test is used to analyze the electrochemical properties.The surface area of the expansive soil is also measured.The test results show that the water-holding capacity of the expansive soil decreases after improved by ISS,correspondingly,the swelling capacity weakens.The mineral component of tested soil has no significant change,however the interlayer spacing（d001） shifts to a smaller one,indicating the loss of hydration between interlayer of montmorillonite.Through ion exchange,ISS replaces surface hydrophilic cations in the particles of the expansive soil and promotes a reduction of cation exchange capacity,and the main component of the exchangeable cations is Ca2＋.Moreover,Zeta potential and surface area decrease,which enhances the connection between soil particles.The mechanism of action of ISS on the expansive soil can be explained as follows：through a series of complex surface physicochemical reactions including cation exchange,absorption and coverage,the water sensitivity and hydrophilic between interlayers weaken,the structure double electric layer is changed,and the thickness of absorbed water is reduced,consequently,water stability and engineering properties are greatly improved.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2011年第4期648-654,共7页
Chinese Journal of Geotechnical Engineering
基金
高等学校博士学科点专项科研基金项目(200804910504)
关键词
离子土固化剂
膨胀土
黏土矿物
理化性能
改性机制
ionic soil stabilizer
expansive soil
clay mineral
physicochemical property
mechanism of improvement
作者简介
作者简介：刘清秉（1984-），男，安徽无为人，博士研究生，从事土力学及特殊土改良研究。E-mail：liuqingbing_1357@163．com。
