一种应用微电子流效应测定土壤含水量的新方法

摘要

土体含水量是岩土工程的重要参数。为了测量这一参数，在分析现有土壤含水量测试方法优缺点的基础上，提出了一种以微电子流效应测定土中含水量的新方法。该方法是将传感器与被测土样耦合在一起，然后对传感器施加100 MHz 的高频交流电流，并产生交流磁场，使被测土样中的电子作同频率的自旋极化运动，从而产生微电子流，通过微电子流的强弱来分辨出水分含量高低。对黄河粉土和桂林红黏土进行了试验，研究了在不同质量、不同密实程度条件下土样的吸水量和吸水速率，并用已知干密度和含水量的环刀样对传感器进行了初步标定。试验结果表明，该方法可以快速有效地测出土样持水量和吸水速率，可测定环刀样和小到0.3 g 土样的含水量。%Soil water content is an important parameter in geotechnical engineering.In order to test this parame-ter,the advantage and limitations of previous achievements about the method of water content detecting in soil are analyzed and a new method of micro-electronic current coupling effect is proposed.Sensor and soil sample measured are coupled together.A current of 100 MHz is applied to the sensor to produce AC magnetic field,so that the electron in the soil samples measured is made with spin polarization movement at the same frequency. Micro-electronic current comes from the spin polarization movement,and the strength of micro-electronic current is closely related to the water contented in soil,and there is a linear relationship between the micro-electronic current and the water content.The Yellow River silt and Guilin red clay are used in the test.The amount of wa-ter absorption and water absorption rate are studied in soil of various mass and different levels of density.A cali-bration of the sensor is made of the ring sample with known dry density and water content.The results show that the new method is effective and can measure the water content of the ring samples and soil sample small to 0.3 g.