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基于一维室内固结试验,分析了初始状态和干湿循环状态下红黏土固结变形特性,并对固结试验过程中的保湿方法进行了改进。研究结果表明,压缩试验的保湿方法建议采用预先补水+湿毛巾覆盖的措施,需要补充水分的多少根据散失的水量来定。当含水率介于最佳含水率-2%~最佳含水率之间,孔隙比、压缩变形系数、压缩系数变化幅度不大。当含水率大于最佳含水率后,孔隙比、压缩变形系数、压缩系数随含水率的增加变化幅度较大。从控制路基工后沉降的角度考虑,建议路基压实时的含水率介于最佳含水率-2%~最佳含水率之间。压实红黏土应力~应变关系可用ε/p=Kp~n式来表达。干湿循环后红黏土压缩系数明显比初始状态的压缩系数要大,且随着循环次数的增加,压缩系数增大,前3次循环压缩系数增加较大,第4次和第5次循环压缩系数趋于稳定。建议在路基沉降计算中采用长期压缩系数a_(1-2)指标(即第4次或第5次循环的压缩系数),使得计算结果更加符合实际情况。
Based on the one-dimensional indoor consolidation experiment, the deformation characteristics of red clay under initial condition and dry-wet cycle are analyzed, and the moisture conservation method in consolidation test is improved. The results show that the compression test moisturizing method is recommended to pre-pay + wet towel coverage measures, the amount of water to be added depends on the amount of water lost to be set. When the moisture content is between the best moisture content of 2% ~ the best moisture content, the void ratio, compressive deformation coefficient, compression coefficient change range is not big. When the moisture content is greater than the optimum moisture content, the void ratio, compressive deformation coefficient and compressibility coefficient vary greatly with the increase of water content. From the perspective of control subgrade settlement, it is suggested that the moisture content of subgrade compaction is between the best moisture content of 2% ~ the best moisture content. Compaction of red clay stress ~ strain relationship can be used ε / p = Kp ~ n expression. The compression coefficient of red clay after the wet-dry cycle is obviously larger than that of the initial state. With the increase of the number of cycles, the compression coefficient increases, the compression coefficient of the first three cycles increases greatly, and the compression of the fourth and fifth cycles The coefficient tends to be stable. It is suggested that the long-term compressibility a_ (1-2) index (that is, the compression coefficient of the 4th or 5th cycle) should be adopted in the subgrade settlement calculation to make the calculation more in line with the actual situation.