滤纸基质吸力率定曲线的率定方法

发布时间：2018-01-30 15:13

本文关键词： 非饱和土滤纸基质吸力率定　出处：《矿冶工程》2017年05期 　论文类型：期刊论文

【摘要】：针对以往采用压力板仪率定滤纸基质吸力试验方法无法真实反映滤纸实际测量时所处土体环境的问题,提出了一种新的率定滤纸基质吸力试验方法。研究结果表明,采用压力板仪利用新方法测定试样的基质吸力,试验前期排水较集中,随后逐渐减少,直至不排水或发生回吸;初始12 h内的排水量并不是一直随基质吸力增大而增多,而是在基质吸力100 k Pa时出现峰值;土水平衡过程中,试样并非一直处于排水状态,因为回吸,累计排水量会出现峰值;达到土水平衡状态时的最终实际排水量和累计排水量随基质吸力增大而增加。基质吸力越大,达到土水平衡所需时间越长。在基质吸力较小的条件下,同一基质吸力下采用新的试验方法测得的滤纸达到平衡时的含水率高于原有方法测得的含水率。Van Genuchten模型能较好拟合高液限红粘土土水特征曲线和滤纸基质吸力率定曲线。滤纸基质吸力率定曲线的准确性受率定环境的影响很大,在进行率定试验时不仅要考虑环境温度和平衡时间,更要考虑所测土体的土性以及滤纸与所测土体的接触方式。
[Abstract]:Aiming at the problem that the suction test method of filter paper based on pressure plate instrument can not truly reflect the soil environment in the actual measurement of filter paper. A new method of matrix suction test for constant filter paper was proposed. The results showed that the suction of the sample was measured by a new pressure plate instrument, the drainage was concentrated in the early stage of the test, and then decreased gradually. Until no drainage or suction occurs; In the initial 12 h, the displacement did not increase with the increase of the matrix suction, but the peak value appeared at 100 KPA of the matrix suction. In the process of soil-water balance, the sample is not always in the drainage state, because the accumulative displacement will appear the peak value; The final actual displacement and cumulative displacement increase with the increase of the matrix suction. The larger the matrix suction, the longer the time to achieve soil-water balance. The moisture content of filter paper measured by the new test method under the same substrate suction is higher than that measured by the original method. The Genuchten model can fit well the characteristic curve of high liquid limit red clay soil and the curve of filter paper matrix suction. The accuracy of filter paper matrix suction determination curve is greatly affected by the setting environment of filter paper. It is necessary to consider not only the environmental temperature and equilibrium time, but also the soil properties and the contact mode between the filter paper and the measured soil.
【作者单位】：湖南城建职业技术学院;湖南科技大学岩土工程稳定控制与健康监测省重点实验室;
【分类号】：TU411
【正文快照】： 基质吸力是描述非饱和土力学性质的重要参数,水土特征曲线(即基质吸力与土壤含水率的关系曲线)是描述基质吸力的重要指标[1]。根据测试方式的不同,基质吸力测试方法分为直接法(张力计、轴平移技术等)和间接法(滤纸法、湿度计法、电/热传导传感器法等)两类[2],其中滤纸法通过测

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