胶结土改性分散性土冻融特性与微观机理研究  

Freeze-thaw characteristics and micromechanism of cemented soil modified dispersived soil

作　　者：王宇 李兆宇 苏安双 于沭[3] 庄广志 WANG Yu;LI Zhao-Yu;SU An-Shuang;YU Shu;ZHUANG Guang-Zhi(Heilongjiang Provincial Hydraulic Institute,Harbin 150080,China;Heilongjiang Seasonal Frozen Soil Region Enginerring Frozen Soil Key Laboratory,Harbin 150080,China;China Institute of Water Resources Hydropower Research,Beijing 100038,China)

机构地区：[1]黑龙江省水利科学研究院,哈尔滨150080 [2]黑龙江省季节冻土区工程冻土重点实验室,哈尔滨150080 [3]中国水利水电科学研究院,北京100038

出　　处：《黑龙江大学工程学报》2023年第1期83-91,共9页Journal of Engineering of Heilongjiang University

基　　金：黑龙江省自然科学基金联合引导项目(LH2019E124);黑龙江省重点研发计划指导类项目(GZ20210208)。

摘　　要：利用胶结土对堤防工程筑堤分散性土进行改性,通过分散性鉴定试验、冻融循环试验、无侧限抗压强度试验及SEM扫描电镜试验,分析了改性效果,揭示了冻融循环对土体无侧限抗压强度的影响规律,并给出了改性机理。结果表明,胶凝材料总用量6%,双掺石灰、粉煤灰和三掺水泥、石灰、粉煤灰两种改性方案可有效抑制土的分散性,转变为非分散性土;胶结土的应力-应变曲线均为应变软化型,破坏应变在2%以内,无侧限抗压强度提高2.5~4倍;胶结土的无侧限抗压强度随冻融循环次数的增加而降低,相比分散性土降低幅度明显减小;胶结土中石灰、水泥水化反应形成的胶结网络增加了土颗粒间的联结力,粉煤灰起到物理充填作用提高土体密实度,宏观表现为无侧限抗压强度的提升,有效抑制冻融循环对土体强度的衰减。The dispersive soil of a dike project in Heilongjiang Province is modified by cemented soil.Through the dispersion identification test,freeze-thaw cycle test,unconfined compressive strength test and SEM scanning electron microscope test,modification effect,influence law of freeze-thaw cycle on unconfined compressive strength of soil and modification mechanism are analyzed.The test results show that the total amount of binding material is 6%,and the two modification schemes of double mixing lime and fly ash and three mixing cement,lime and fly ash can effectively inhibit dispersion of soil and change into non dispersive soil;The stress-strain curves of cemented soil are strain softening,the failure strain is less than 2%,and the unconfined compressive strength is increased by 2.5~4 times;The unconfined compressive strength of cemented soil decreases with the increase of freeze-thaw cycles,which is significantly lower than that of dispersed soil;The cementation network formed by the hydration reaction of lime and cement in cemented soil increases the bonding force between soil particles,and fly ash plays the role of physical filling and improves the compactness of soil.The macro performance is the improvement of unconfined compressive strength,which can effectively inhibit the attenuation of soil strength caused by freeze-thaw cycle.

关 键 词：胶结土 分散性土 冻融循环 无侧限抗压强度 改性机理 

分 类 号：TU411[建筑科学—岩土工程]