摘要
目的研究MJS加固水泥土的热物理特性,解决MJS与冻结止水联合加固冻结设计的水泥土热物理参数取值问题.方法通过自制冻结温度测试系统测定MJS水泥土冻结温度,通过ISOMET便携式热特性分析仪测定导热系数及容积热容量,采用SHR-6型水泥水化热测定仪测定水化热.结果MJS水泥土冻结温度随水泥掺量增大而降低,随龄期增长先降低后升高再降低,冻结温度在-0.64^-1.40℃;冻结与常温MJS水泥土导热系数均随龄期增长及水泥掺量增大而减小;常温MJS水泥土容积热容量随龄期增长而减小、随水泥掺量增大先减小后增大,冻结MJS水泥土容积热容量随龄期增长及水泥掺量增大而缓慢减小;随水泥掺量增大,MJS水泥土水化放热速率峰值提高,而到达放热速率峰值的时间均为水化15 h左右;水化热在28 d龄期内,随龄期增长和水泥掺量增大而增大,龄期28 d时,水泥掺量由40%每增加1%,水化热增加0.95%.结论MJS水泥土热物理参数受水泥掺量及龄期影响较大,人工冻结加固方案设计应充分考虑水泥掺量和龄期的影响.
The thermal physical properties of MJS reinforced cement soil were studied to solve the cement soil thermophysical parameter problem of the freezing design in MJS and frozen water stop combined reinforcement method.The freezing temperature of MJS cement soil was measured by the self-made freezing temperature testing system.The thermal conductivity and volumetric heat capacity were measured by ISOMET portable thermal characteristic analyzer,hydration heat with SHR-6 cement hydration heat tester.The freezing temperature of MJS cement soil decreases with the increase of cement content,and decreases firstly,then increases and finally decreases with the increase of age.The freezing temperature ranges from-0.64℃to-1.40℃.The thermal conductivity of frozen and normal temperature MJS cement soil decreases with the increase of age and cement content.At room temperature,the volume heat capacity of MJS cement soil decreases with the increase of age,and it decreases firstly and then increases with the increase of cement content.The volume heat capacity of frozen MJS cement soil decreases slowly with the increase of age and the increase of cement content.With the increase of cement content,the heat release rate peak of cement soil hydration increases.The time to reach the peak of exothermic rate is about 15h of hydration.Hydration heat increases with the increase of age and cement content during the 28d period.At the age of 28 days,for every 1%increase in cement content from 40%,the hydration heat of cement soil increase by 0.95%.The cement content and age affect the thermal physical properties of MJS cement soil greatly,so they should be fully considered in the design of the artificial freezing method.
作者
杨平
陈驰
张存
何文龙
YANG Ping;CHEN Chi;ZHANG Cun;HE Wenlong(College of Civil Engineering,Nanjing Forestry University,Nanjing,China,210037;China Railway Liuyuan Group Co.Ltd.,Tianjin,China,300308)
出处
《沈阳建筑大学学报（自然科学版）》
CAS
CSCD
北大核心
2020年第4期661-669,共9页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家自然科学基金项目(41902286)。
关键词
MJS水泥土
冻结温度
导热系数
容积热容量
水化热
MJS cement soil
freezing temperature
thermal conductivity
volumetric heat capacity
the hydration heat
