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以桂林红黏土为研究对象,采用压力板法、滤纸法和饱和盐溶液蒸气平衡法3种方法研究在全吸力范围内原状样和压实样的土水特性,并结合压汞试验研究其孔隙分布。试验结果表明:当吸力约小于10 MPa时原状样的土水特征曲线略低于压实样,主要原因是原状样内部裂隙随吸力的增加而不断发展;当吸力约大于10 MPa时两者的土水特征曲线几乎重合。原状和压实桂林红黏土样的土水特征曲线与典型的土水特征曲线不同,即在过渡段均不是单一直线。此外,原状样为单峰孔隙结构,压实样则为双峰孔隙结构,原状样的最终收缩变形量比压实样大。不同干密度的压实样内部颗粒间孔隙分布几乎相同,而积聚体间孔隙或积聚体内孔隙相对较大孔隙存在差异;由此可解释在高吸力范围内不同干密度压实样的含水率与吸力关系土水特征曲线几乎重合;以饱和度与吸力关系表示时,干密度越大,土水特征曲线越高。
Taking Guilin red clay as the research object, this paper studied the soil-water characteristics of the original sample and the compacted sample in the full suction range by pressure plate method, filter paper method and saturated salt solution vapor balance method, distributed. The results show that when the suction is less than 10 MPa, the soil-water characteristic curve of the original sample is slightly lower than that of the compacted sample. The main reason is that the internal fractures of the original sample continue to develop with the increase of suction force. Soil water characteristic curve almost coincide. The original and compacted Guilin red clay-like soil-water characteristic curve is different from the typical soil-water characteristic curve, that is, it is not a single straight line in the transitional section. In addition, the original sample is a single-peaked pore structure, while the double-peaked pore structure is observed for the compacted sample. The final shrinkage deformation of the original sample is larger than that of the compacted sample. Compacted samples with different dry densities had almost the same pore distribution among the intergranular particles, but there were differences between the larger pores in the intergranular pores or in the aggregates; thus, it was possible to account for the difference between the moisture content of the compacted samples with different dry densities The soil-water characteristic curve of suction relationship almost coincides; when the relationship between saturation and suction is expressed, the greater the dry density, the higher the soil-water characteristic curve.