人工冻结作用下淤泥质黏土冻胀特性试验研究

冻结法施工在上海软土地区隧道附属设施建设中(如隧道旁通道、地下泵房等)得到较多地应用。上海地铁隧道一般位于第④层饱和淤泥质黏土层中,饱和淤泥质黏土层冻胀变形使地铁隧道管片破裂、渗水或漏泥,严重影响隧道管片质量与地铁安全运营。以上海第④层饱和淤泥质黏土为研究对象,通过室内冻胀试验,研究冷端温度对土体的冻胀力以及冻胀率的影响规律,结果显示土样冻胀率以及冻胀力与冷端温度具有较好的线性关系。通过冻结温度试验测出了土体的冻结温度,同时建立了第④层饱和淤泥质黏土的冻结温度场,进一步揭示了冻结锋面的发展与时间的关系。研究成果为上海地铁隧道冻结法设计、施工与地铁安全运营提供了有价值的参考。

Frost-heaving behaviors of mucky clay by artificial horizontal freezing method

With the development of undergroud structures in Shanghai,the ground freezing method has been more and more widely used in the construction of appurtenant parts of tunnels(such as the soil reinforcement of passways and pump house of tunnels).Exploring frost-heaving behaviors of artificial freezing soil is a key technology and an important research about artificial freezing method for municipal underground space.After the frost-heaving tests,the relationship between frost-heaving and freeezing end temperature is studied.The frost-heaving ratio and the frost-heaving stress are in linear relation with the freeezing end temperature.The freezing temperature of soil is measured by freezing temperature tests,and the freezing temperature distribution field of the soil samples is established.The relationship between freezing front and time is further revealed.