一种复合加固剂改良砂土的强度试验研究

摘要

This paper aims to examine composite curing method based on polymeric soil consolidator and fiber material to reinforce the sand.Especially the test uses different concentrations of polyurethane curing agent and different content polypropylene fiber.All of the composite soil samples are subjected to the direct shear test and the unconfined compression test in this experiment.The results and the mechanism are discussed.The following are found.When the composite reinforcing agent in curing agent concentration is certain,unconfined compressive strength and cohesion of sands increase first and then decrease as the fiber content increases.They reach their peak values at the fiber contents of 0.3％ and 0.2％.When the fiber content of composite reinforcement agent is certain,the unconfined compressive strength and cohesion restriction of sands increase as the curing agent concentration increases,but the angle of internal friction has little change.Finally,composite reinforcing agent is a combination of physical and chemical reinforcement methods.It can quickly and effectively improve the strength of sand,and also provide a reference for the further research and application of composite reinforcement materials.%本研究采用聚丙烯纤维和聚氨酯型固化剂复合加固材料(简称复合加固剂)对砂土进行改良,对不同配比的复合加固剂改良砂土的强度,进行了无侧限抗压和直剪试验研究,并对其改良机理进行较为深入的分析.试验结果表明,复合加固剂改良砂土的无侧限抗压强度和剪切强度均得到了一定程度的提高.当复合加固剂中固化剂的浓度一定时,砂土的无侧限抗压强度和黏聚力均随着纤维含量的增加先增加后减少,分别在纤维含量0.3％和0.2％左右达到峰值;当复合加固剂中纤维含量一定时,砂土的无侧限抗压强度和黏聚力均随着固化剂浓度增加而增加,而内摩擦角变化不大.综合试验结果和施工可行性,建议复合固化剂在改良砂土应用中的最佳配比为聚氨酯固化剂浓度30％,聚丙烯纤维含量0.2％.复合加固剂是结合物理和化学加固方式,能够有效地提高砂土强度.本研究结果为复合加固材料的进一步研究和应用提供一定的参考依据.