人工冻结水泥改良土冻胀融沉特性研究

Study on Frost Heave-Thaw Settlement Characteristics of Artificially Frozen Cement Improved Soil

针对人工冻结法缺陷引起冻胀融沉的施工问题,采用室内试验的方式,研究不同水泥掺量和养护龄期作用下冻结水泥改良土冻胀融沉性能,并通过数值模拟与试验数据相互验证。研究表明,随水泥掺量的增加,样本冻胀融沉率逐渐降低;水泥掺量达到8%时,样本的冻胀融沉抑制率最优;养护龄期在14 d后,冻胀融沉率基本不变;在12%水泥掺量下,模拟值与实测值的冻结锋面发展规律较为接近;冻结初期,冻结锋面向下传递速率较快,越靠近暖段冻结锋面传递速率越慢,两者到达冻结锋面80 mm处,模拟值较快,差值为1.5 h。研究结果表明数值模拟能有效反映水泥改良土的冻胀机理。

For the frost heave-thaw settlement construction problems caused by the defects of artificial freezing method,this paper adopts the method of laboratory test to study the frost heave-thaw settlement performance of frozen cement impoved soil under dif⁃ferent cement contents and curing ages and verifies it throught the numerical simulation and test data.The results show that with the in⁃crease of cement content,the frost heave-thaw settlement rate of the sample decreases gradually.When the cement content reaches 8%,the inhibition rate of frost heave-thaw settlement is the best.After 14 days of curing,the frost heave-thaw settlement rate re⁃mained basically unchanged.At 12%cement content,the frozen front development law of the simulated value is close to that of the measured value.At the beginning of freezing,the downward transfer rate of the frozen front is faster,and the closer the frozen front is to the warm section,the slower the transfer rate is.The simulated value is faster when the two sides reach 80mm of the frozen front,and the difference is 1.5 h.The results show that numerical simulation can effectively reflect the frost heave mechanism of cement im⁃proved soil.