重塑石灰土的强度恢复方法与机制初探  

Strength recovered method and mechanism for remolded lime soil

作　　者：谈云志[1] 喻波[1] 刘云[1] 左清军[1] 胡莫珍 郑爱[1] 

机构地区：[1]三峡大学三峡地区地质灾害与生态环境湖北省协同创新中心,湖北宜昌443002

出　　处：《岩土力学》2015年第3期633-639,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金项目资助(No.51009084);博士后科学基金项目(No.2013M542057);三峡大学土木与建筑学院创新基金项目(No.CX2014001)

摘　　要：石灰稳定土工程翻修改造后会产生大量的石灰土弃渣,为避免污染环境和节约工程投资,需重新利用破碎的石灰土进行填筑。但石灰土破碎后强度急剧降低,需要添加胶凝材料提升其力学性能。以重塑石灰土为研究对象,通过添加5%石灰或水泥进行再改良,对比分析两种再改良土的强度和压缩性等力学指标,结果表明,石灰再改良土的力学特性优于水泥再改良土。借助粒度分析、电镜扫描、X衍射和热重分析试验手段揭示了石灰再改良土性能优越的内在机制,发现石灰再改良土中的石灰和石灰土团粒能形成很好的胶结;但水泥未能和石灰土团粒形成有效胶结,自身形成了边-面和边-边接触的片状多孔架构。重塑石灰土残存的氢氧化钙是引起水泥再改良土性能劣于石灰再改良土的主要诱因。There are large amounts of crushed lime stabilized soils after the rebuilding of engineering projects which are constructed with limed soils many years ago. It＇s necessary to reuse them to avoid environmental pollution and to save construction investment.But the strength of crushed lime soil would significantly reduce. So, the gel materials are added to enhance the mechanical properties of crushed lime soil. The remolded lime soil is re-stabilized through adding 5% lime or cement. Comparisons of strength and compressibility between the lime re-stabilized soil and cement re-stabilized soil are made. The resu＞s show that the mechanical properties of lime re-stabilized soil are better than those of cement re-stabilized soil. Furthermore, it reveals the internal mechanism of superior performance for lime re-stabilized soil with particle size analysis, scanning electron microscope, X-Ray diffraction and thermo gravimetric analysis tests. It is found that the lime and limed-aggregates in lime re-stabilized soil can be cemented up well.But cement fails to form effective cementation with limed-aggregates. The cement re-stabilized soil forms edge-plane and edge-edge contact porous structure. The Calcium hydroxide remained in the remolded lime soil is the major factor which makes the property of cement re-stabilized soil inferior to the lime re-stabilized soil.

关 键 词：重塑石灰土 强度再生 红黏土 微观形貌 

分 类 号：TU43[建筑科学—岩土工程]