摘要
通过对不同掺灰率、不同干湿循环次数下的保养开展养生和未养生的重塑膨胀土与石灰改良土不同干湿循环次数条件下的三轴剪切试验以及电镜扫描试验可知,重塑膨胀土在养生条件和未养生条件下c、值随干湿循环次数增加均呈降低趋势,但经历养生后试样的下降幅度更大;石灰改良土的应力-应变曲线在养生-未养生条件下均为应变软化型,当未养生时,随干湿循环次数的增加c、值逐渐上升,当养生后,随干湿循环次数的增加,c值先减后增,值先增后减,且增减幅度掺灰率的提升而增加;由电镜扫描结果可知,未掺灰的试样经养生后试样内部层、片状结构逐渐发育完善,胶结能力提升,但无化合反应,颗粒尺寸变化较小;当掺加石灰改良后,未养生条件下在干湿循环过程中试样内部发生剧烈的化合置换反应,增加了颗粒间的胶结能力及粒径尺寸,而养生过后的试样内部石灰与土体的反应较为充分,但受掺灰率影响,试样内部仍存在部分膨胀性离子,随干湿循环过程的进行,试样内部裂隙逐渐发育,石灰与试样内部膨胀性离子进一步反应,最终导致值呈现不规律性变化。
Through the triaxial shear test and scanning electron microscope test of the cured remolded expansive soil and lime improved soil under different dry and wet cycles and the curing under different lime mixing rates and different dry and wet cycles, it can be seen that the c and value of the remolded expansive soil under the curing conditions and the non curing conditions decrease with the increase of dry and wet cycles, but the decline of the sample after curing is greater;The stress-strain curve of lime improved soil is strain softening under the curing and non curing conditions. When the curing is not carried out, the c and value gradually increase with the increase of the number of dry and wet cycles. When the curing is completed, the c value first decreases and then increases with the increase of the number of dry and wet cycles, and the value first increases and then decreases, and the increase and decrease range increases with the increase of the ash mixing rate;It can be seen from the scanning results of the electron microscope that after curing, the inner layer and sheet structure of the sample without ash are gradually developed and perfected, and the cementation ability is improved, but there is no chemical reaction, and the particle size changes little;When lime is added for improvement,severe chemical replacement reaction occurs in the sample during the dry wet cycle without curing, which increases the cementation ability and particle size between particles. The reaction between lime and soil in the cured sample is relatively sufficient, but due to the influence of the lime mixing rate, there are still some expansive ions in the sample. With the dry wet cycle, the cracks in the sample gradually develop, The lime further reacts with the expansive ions in the sample, resulting in an irregular change in the value.
作者
韩赟
宋正民
穆彦虎
赵成江
HAN Yong;SONG Zhengmin;MU Yanhu;ZHAO Chengjiang(Gansu Civil Aviation Airport Group Co.,Ltd.,Lanzhou 730087,China;China Railway 14th Bureau Group 4th Engineering Co.,Ltd.,Jinan 250000,China;State Key Laboratory of Frozen Soils Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Northwest Research Institute Co.,Ltd.,of CREC,Lanzhou 730000,China)
出处
《建筑结构》
CSCD
北大核心
2022年第S02期2194-2201,共8页
Building Structure
关键词
膨胀土
剪切模量
三轴试验
干湿循环
养生周期
expansive soils
shear modulus
triaxial test
wetting-drying cycles
curing period
