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吸力对非饱和土的性质有着重要的影响,探讨吸力与非饱和红黏土含水率之间的关系可以有效地服务地方经济。用蒸汽平衡法研究了高吸力段(3~368 MPa)广西贺州红黏土持水特性。研究表明,质量含水率或者饱和度随着控制吸力的增加而减小,随着吸力的降低而增大;本组试验在控制吸力值为21.82 MPa时,曲线存在突变点,此时试样吸排水速率发生比较大的变化;脱湿曲线与吸湿曲线间存在滞回效应,吸力值小于突变点的时候,滞回现象明显。不同初始含水率的土样对应的吸力与含水率间关系曲线基本重合,而吸力与饱和度间关系曲线则不重合,主要与含水率的变化和土体的胀缩变形不成正比有关,孔隙比和吸力间的关系曲线也进一步说明了这一点,因此分析红黏土土水特征时要根据实际情况选用坐标变量。所获结果为当地边坡土体持水特性分析提供了基础数据,有助于该地区工程实践的防灾减灾。
Suction has an important influence on the properties of unsaturated soils, and the relationship between suction and water content of unsaturated red clay can effectively serve the local economy. The water balance characteristics of red clay in He Su state of Guangxi Province (3 ~ 368 MPa) were studied by steam balance method. The results show that the mass water content or saturation decreases with the increase of the control suction and increases with the decrease of the suction. In this test, when the control suction value is 21.82 MPa, there is a sudden change in the curve. At this time, the sample suction Drainage rate has a relatively large change; there is a hysteresis effect between the dewetting curve and the hygroscopic curve. When the suction value is less than the abrupt point, the hysteresis is obvious. The curves of suction and water content of soil samples with different initial moisture contents basically coincide, while the curves of suction and saturation do not coincide with each other, mainly due to the fact that the change of moisture content is not directly proportional to the expansion and contraction deformation of the soil. And the relationship between the suction curve is also further illustrates this point, so the analysis of red clay soil water characteristics according to the actual selection of coordinate variables. The results obtained provide the basic data for the analysis of water retention characteristics of local slope soil so as to contribute to the disaster prevention and reduction of engineering practice in this area.