冻结水泥土无侧限抗压试验研究

Test research on unconfined compressive strength of freezing cement soil

城市地铁盾构进出洞及联络通道施工中常常采用水泥土预先加固辅以人工冻结法补充加固的施工工艺,为掌握冻结水泥土的力学性能及相关设计参数,开展了系列冻结水泥土无侧限抗压性能室内试验研究,研究结果表明:水泥土无侧限抗压强度随温度的降低、水泥掺入比的增加呈线性增大,随养护龄期的增加呈对数增大;水泥土的抗压强度和弹性模量随着温度的降低基本呈线性增大,在常温下随水泥掺入比呈线性增大,在-10℃下随水泥掺入比呈指数增大,并随着养护龄期的增加呈对数增大;温度、水泥掺入比和龄期三个因素中温度对水泥土抗压强度的影响最大;随水泥掺入比、龄期的增加,冻结水泥土与常温水泥土强度及弹性模量差异呈指数规律减小,最终趋于稳定比值。

To provide the freezing design parameters for the project that needs the cement reinforced soil,the artificial ground freezing method for the added reinforcement in urban subway constructions is used.In order to master the mechanical properties and design parameters of frozen cement soil,a series of tests research on the unconfined compressive test of freezing cement soil in laboratory are conducted.The tests showe that with the decreasing temperature or the increasing cement content,the unconfined compressive strength of the cement soil linearity increases.With the increasing curing period,the unconfined compressive strength of the cement soil logarithmically increases.With the decreasing temperature,the elastic modulus of cement soil linearly increases.In normal temperature,the elastic modulus increases linearly with the increase in cement ratio.In temperature of-10℃,the elastic modulus exponential increases with the increase in cement ratio,and the elastic modulus logarithmically increases with the cement ratio increases.Of the three factors of temperature,cement ratio and age,the impact of temperature on the compressive strength of cement soil is the largest.With the increasing cement content and curing period,the ratio of the compressive strength ato the compressive strength of freezing cement soil and cement soil at room temperature exponentially decreases,and eventually stabilizes.