稻壳灰-水泥固化淤泥土力学特性及微观机理研究  

Mechanical properties and micro-mechanisms of RHA-cement solidified sludge

作　　者：李丽华 韩琦培[1,2] 杨星 肖衡林 李文涛 黄少平[1,2] Li Lihua;Han Qipei;Yang Xing;Xiao Henglin;Li Wentao;Huang Shaoping(School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068,China;Ecological Road Engineering Research Center,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,湖北武汉430068 [2]湖北工业大学湖北省生态道路工程研究中心,湖北武汉430068

出　　处：《土木工程学报》2023年第12期166-176,共11页China Civil Engineering Journal

基　　金：武汉市应用基础前沿专项(2020020601012278);湖北工业大学杰出人才基金(XJ2021000501);湖北省创新群体项目(2020CFA046)。

摘　　要：我国许多地区河道湖泊环境受损,淤泥淤积速度加快,淤泥质软土地区易发生严重的地基或边坡失稳,通过固化/稳定化技术对淤泥土进行资源化利用具有重要意义。提出利用稻壳灰和水泥进行淤泥固化处理,通过无侧限压缩试验、三轴固结不排水试验评价固化土力学特性;并结合核磁共振、X射线衍射和电子显微镜扫描试验,分析稻壳灰掺量对固化土孔隙尺寸、矿物成分、微观形貌的影响规律,揭示稻壳灰-水泥固化淤泥土的机理。研究表明:稻壳灰能显著提高固化淤泥土强度,稻壳灰-水泥土强度随稻壳灰掺量的增加先增后减,随龄期的增长而增加;当水泥掺量8%时,稻壳灰最优掺量为15%,稻壳灰-水泥土应力应变曲线为应变软化型,抗剪强度参数随着养护龄期增大而增大。稻壳灰-水泥土养护28d试样的XRD图中出现水化硅酸钙(CSH)衍射峰,而T2分布曲线中大孔峰值及面积明显降低,同时观察到SEM图中大量网状水化硅酸钙凝胶,该凝胶能够起到填充土体孔隙、联结土颗粒的作用。The environment of rivers and lakes in many areas of China is damaged,the rate of sludge deposition is accelerated,and the sludge area is prone to serious ground or slope instability.It is of great significance to utilize the solidification/stabilization technology for a resource use of sludge.In this work,it is proposed to use rice husk ash(RHA)and cement to solidify sludge,and the mechanical properties of solidified soil are evaluated by the tests on unconfined compressive strength and undrained triaxial consolidation of the soil.By nuclear magnetic resonance test,Xray diffraction and scanning electron microscope,the effects of RHA ingredient on pore size,mineral composition,and micro-morphology are analyzed,and the solidification mechanism of RHA-cement for sludge is revealed.The results show that the strength of sludge can be significantly improves by RHA,the strength of RHA-cement soil increases firstly and then decreases with the increase of RHA content,and it also increases with the increase of age.When the content of cement is 8%,the optimal content of rice husk ash is 15%.The stress-strain curve of RHA-cement soil appears to be the strain-softening type,and the shear strength parameters increase with the curing age.Calcium silicate hydrate(CSH)diffraction peak may appear in the XRD pattern of the RHA-cement soil sample with a curing period of 28 days,while the peak and area of macropore in T2 distribution curve amy decrease obviously,and a large number of reticulated calcium silicate gels,which fill the pores of soil and bond soil particles,are observed in the SEM diagram.

关 键 词：淤泥 稻壳灰 无侧限抗压强度 三轴试验 微观结构 

分 类 号：TU447[建筑科学—岩土工程]