摘要
为研究不同初始含水率和有机质含量下水泥土的抗压、抗折、抗剪强度变化规律及其相互关系,选取珠海典型软土制备不同水泥土试样,分别进行无侧限抗压试验、抗折试验、压缩试验以及三轴剪切试验。分析不同初始含水率、水泥掺量和有机质含量对水泥土抗压、抗折和抗剪强度的影响。结果表明:水泥土无侧限抗压强度与抗折强度均随初始含水率和有机质含量的升高而降低,且水泥掺量越大,降低的幅度越大。初始含水率从40%提高到80%,抗压强度降低幅度达80%;有机质含量从3%升至20%,抗折强度降低约30%,抗压强度降低幅度达35%,且初始含水率越高,有机质含量对强度的影响程度越大。压缩模量随水泥掺量的增加而提高,提高的幅度随含水率升高先增加后减小。三轴试样剪切破坏形式随着初始含水率的提高由脆性向塑性转变,内摩擦角和黏聚力随含水率的升高、水泥掺量的降低呈非线性下降趋势,初始含水率从40%增至80%时水泥土的内摩擦角降低0.25~0.42倍,黏聚力降低约0.52倍。基于试验结果,建立抗压强度与抗折强度、压缩模量、黏聚力之间的线性经验公式,并根据无侧限抗压强度与水泥掺量和有机质含量的经验关系,给出不同初始含水率和有机质含量下水泥土搅拌桩现场施工水泥掺量取值范围,为软土区域水泥土搅拌桩的设计和施工提供参考。
To investigate the variation and interrelationships of compressive strength,flexural strength,and shear strengths of cement soils with different initial water contents and organic matter contents,various specimens were prepared using typical soft soil in Zhuhai and unconfined compression test,flexural test,consolidation compression test,and triaxial shear test were conduced,respectively.The effects of different initial water content,cement dosage,and organic matter content on the compressive strength,flexural strength,and shear strength of the cement soils were analyzed.The results showed that the unconfined compressive strength and flexural strength of the cement soil reduces with the increase of the initial water content and organic matter content.With the increase of cement dosage,the magnitude of strength decrease also increases.As the initial water content increases from 40%to 80%,the compressive strength is reduced by up to 80%.As the organic matter content increases from 3%to 20%,flexural strength is reduced by about 30%,and compressive strength is reduced by up to 35%.The degree of influence of organic matter content on strength rises as the initial water content increases.The compressive modulus improves with the increase of cement dosage,and the range of improvement initially increases and subsequently falls with the increase of water content.The shear failure mode of triaxial specimen changes from brittleness to plasticity with the increase of initial water content.When the water content increases or the cement dosage decreases,the internal friction angle and cohesion show a non-linear downward trend.As the initial water content increases from 40%to 80%,the internal friction angle of cement soil decreases by 0.25~0.42 times,and the cohesion reduces by about 0.52 times.Based on the test results,the linear empirical formulas between the compressive strength and the flexural strength,compression modulus and cohesion were established,respectively.According to the empirical relationship between unconfined compressive strength and cement dosage and organic matter content,the value range of cement dosage in the field construction of cement-soil mixing piles under different initial water content and organic matter content is obtained,which provides a reference for the design and construction of cement-soil mixing piles in soft soil areas.
作者
杨斌财
刘维正
余勇
徐冉冉
李天雄
YANG Bincai;LIU Weizheng;YU Yong;XU Ranran;LI Tianxiong(School of Civil Engineering,Central South University,Changsha 410075,China;Zhuhai Communications Group Co.,Ltd.,Zhuhai 519000,China;National Engineering Research Center of High-speed Railway Contruction Technology,Changsha 410075,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2023年第10期3798-3808,共11页
Journal of Railway Science and Engineering
基金
珠海交通集团有限公司科技研究开发计划课题(JT-KT202001)
国家自然科学基金资助项目(52078500)
湖南省自然科学基金资助项目(2019JJ40344)。
关键词
水泥土
初始含水率
有机质
抗压强度
抗折强度
抗剪强度
cement soil
initial water content
organic matter
compressive strength
flexural strength
shear strength