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接触角变化将直接影响非饱和土中水–气交界面的性质。为研究张力计和轴平移技术测量吸力过程中接触角的变化情况及这种变化对测量结果的影响,以表面化学原理为基础,把退湿分为外力式退湿和蒸发式退湿2种形式;增湿分为外力式增湿和凝结式增湿2种形式。在此基础上分析退湿过程中,张力计和轴平移技术测量吸力时土体中的接触角特性。从理论上断定:退湿过程中,相同含水率下轴平移技术所测得的基质吸力要大于张力计所测;增湿过程中,相同含水率下轴平移技术测得的基质吸力则又小于张力计所测,并通过接触角测量试验和吸力测量试验验证了这一推断。2种测量方法在实际应用中应该对应不同的工况:对于雨水入渗,地下水位下降等非饱和土力学问题应该用轴平移技术试验结果;对于非饱和土的干缩问题则应该用张力计进行测量。
The change of contact angle will directly affect the properties of water-air interface in unsaturated soil. In order to study the change of contact angle during suction measurement by tensiometer and axial translation technique and the influence of this change on the measurement results, based on the surface chemical principle, the dehumidification is divided into two types: external force dehumidification and evaporative dehumidification Form; humidification is divided into external humidification and condensation humidification 2 kinds of forms. On the basis of this analysis, the contact angle characteristics of soils in the process of suction measurement were analyzed with tension meter and axial translation technology. It is theoretically concluded that the matrix suction measured by the axial translation technique with the same moisture content is greater than that measured by the tensiometer during the dehumidification process. The matrix suction measured by the axial translation technique with the same water content during the humidification process is less than Tensiometer measured, and through the contact angle measurement test and suction measurement test to verify this inference. Two kinds of measurement methods should correspond to different working conditions in practical application. For unsaturated soil mechanics problems such as rainwater infiltration and groundwater level drop, the results of axial translation test should be used. For the problem of shrinkage of unsaturated soil, tension meter Make measurements.