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采用十二烷基三甲基胺乙内酯(甜菜碱)处治辽西某地膨胀土路基,以提高膨胀土路基结构强度。同时设计试验,揭示甜菜碱处治膨胀土的机理。在测定所用膨胀土基本物理性质参数的基础上,通过CBR试验、无侧限抗压试验、自由膨胀试验、干湿循环后的无侧限抗压试验等,验证甜菜碱对膨胀土的处治作用。试验结果表明甜菜碱能够提高膨胀土的强度和抵抗干湿循环的能力,同时降低膨胀土自由膨胀率,试验条件下的经济掺量为0.6%。此外根据双电层理论分析了甜菜碱处治膨胀土的机理。进而通过吸附试验和阳离子交换试验证明,甜菜碱分子内氮原子上的正电荷、长脂肪碳链、羧基均具有处治膨胀土的作用。
Adopting dodecyltrimethylaminobutyrolactone (betaine) to treat the expansive soil roadbed in a certain area in western Liaoning to improve the structural strength of expansive soil subgrade. At the same time, the experiment was designed to reveal the mechanism of betaine treatment of expansive soils. Based on the determination of the basic physical properties of expansive soils, the effect of betaine on the expansive soils was verified through CBR test, unconfined compressive test, free-expansion test and unconfined compressive test after wet-dry cycle . The results show that betaine can increase the strength of expansive soils and resist wetting and drying cycles, and reduce the expansive soils at the same time. The economic content of betaine is 0.6% under the test conditions. In addition, the mechanism of the treatment of expansive soils with betaine was analyzed based on the theory of electric double layer. Furthermore, it was proved by adsorptive test and cation exchange test that positive charge of nitrogen atom, long aliphatic carbon chain and carboxyl group in betaine molecule all have the effect of treating expansive soil.