DOI: 10.15986j.1006-7930.2018.06.008
选用MgSO4溶液作为侵蚀液,研究了侵蚀液浓度、侵蚀时间对水泥改良砂力学特性的影响,探讨了MgSO4溶液对水泥改良砂的侵蚀规律,试验结果表明,对于水泥掺量2%的改良砂,MgSO4溶液对其无侧限应力应变曲线特征影响较小,而水泥掺量6%、10%的改良砂,当MgSO4溶液浓度小、侵蚀时间短时,在荷载作用下试样能依次经历气孔闭合阶段、线弹性阶段、微缺陷的稳态扩展阶段而破坏,而在MgSO4溶液浓度高、侵蚀时间长的条件下,试样经历气孔闭合阶段后即进入微缺陷的稳态扩展阶段,线弹性阶段特征则不明显.MgSO4溶液对水泥改良砂的侵蚀存在浓度阈值,浓度低于4 g/L时,水泥改良砂无侧限强度在4周内变化并不显著,而MgSO4溶液浓度高于4 g/L时,试样强度的衰减程度则很大.
Choosing MgSO4 solution as the erosion liquid, the effects of erosion concentration and erosion time on the mechanical character of cement modified sand were studied, the erosion law of MgSO4 solution to cement modified sand is discussed, experimental results show that for sand modified by 2 percent cement, MgSO4 solution has little impact on the sand's unconfined stress-strain curve, while for sand modified by 6 and 10 percent cement, when MgSO4 solution concentration is low and erosion time is not long, the specimen would go through successively the Stomatal closure stage、linear elasticity stage、micro-defects's steady expansion stage and then emerges failure under the effect of stress, but when MgSO4 solution concentration is dense and the erosion time is long enough, specimen would enter micro-defects's steady expansion stage after going through the Stomatal closure of the compaction part under the impact of stress, the characteristics of the linear elasticity stage are not obvious. MgSO4 solution has a concentration threshold for the erosion of cement modified sand, when MgSO4 solution concentration is below 4 gram per liter, the unconfined strength of cemented sand does not decrease significantly within 4 weeks, but when the concentration of MgSO4 solution is higher than 4 gram per liter, cemented sand's strength would attenuate rapidly.
