电场作用下水玻璃改良膨胀土正交试验研究

在交流电场条件下水玻璃改良膨胀土影响因素众多,本文利用正交试验的方法研究了Na₂O含量、模数、通电电压和时间4个影响因素对改良膨胀土膨胀率的影响,得出了优化固化条件并初步揭示了其改良机理。试验结果表明,各因素对改良膨胀土膨胀率影响的主次顺序为:Na₂O、模数、通电电压和时间。Na₂O含量越大,通电电压越高,生成的硅酸凝胶越多,改良膨胀土的无荷膨胀率越低;在一定范围内膨胀率随模数增大而增大,但达到极值点后会有少量降低,因为模数过高带来的大量SiO₂会使土颗粒间连接不够紧密;随通电时间增加,改良膨胀土膨胀率先稳定下降再上升,存在下极值点;对比未通电与通电的试验结果表明交流电场条件对膨胀土改良效果有良好的增强作用。综合各试验结果得出最优固化条件为:Na₂O含量2.4%、模数1.6、通电电压100 V、通电时间60 s,为电场作用下水玻璃改良膨胀土的工程应用提供参考。

Orthogonal Test Study on the Improvement of Expansive Soil by Sodium Silicate under Electric Field

There are many factors affecting the improvement of expansive soil by sodium silicate under AC electric field. In this paper, the influence of Na₂O content, modulus, on-line voltage and time on the improvement of expansive soil expansibility is studied by orthogonal test. The optimum solidification conditions are obtained and the improvement mechanism is preliminarily revealed. The test results show that the order of influence of various factors on the expansibility of improved expansive soil is Na₂O, modulus, on-line voltage and time. The higher the Na₂O content and the higher the electrified voltage, the more silicic acid gel, the lower the unloaded expansion rate of the modified expansive soil. In a certain range, the expansion rate increases with the increase of modulus, but it will decrease a little after reaching the extreme value. Because a large number of SiO₂ brought by the high modulus will make the connection between the soil particles insufficiently tight. The experimental results show that the electric field condition has a good effect on the improvement of expansive soil. The optimum solidification conditions are as follows: Na₂O content 2.4%, modulus 1.6, electrification voltage 100V and electrification time 60s, which can provide reference for engineering application of sodium silicate modified expansive soil under electric field.