干湿循环条件下复合固化砂土抗压强度试验研究

Strength characteristics of fiber-reinforced solidified sand under dry-wet cycles

为探究水泥、石灰以及长安大学4号固化剂和多种纤维复合固化砂土在干湿循环后的力学性能,利用正交设计方案进行无侧限抗压强度试验,并将试样进行扫描电镜(SEM)试验和能谱仪(EDS)检测对其微观机理进行分析。研究结果表明:3种固化剂及纤维均能有效提高复合固化砂土的无侧限抗压强度,其中龄期和固化剂品种对复合固化砂土的抗压强度影响最大,干湿循环次数次之,纤维掺量和固化剂掺量有一定的影响,而纤维品种对无侧限抗压强度的影响最小;纤维掺量0.45%,固化剂掺量8%时效果较好;纤维加筋固化砂土的无侧限抗压强度随着干湿循环次数的增加而显著下降。鉴于良好的抗干缩湿胀耐久性能,建议使用8%水泥与0.45%的改性聚丙烯纤维作为固化砂土的复合固化材料。

In order to investigate the mechanical properties of the cement, lime and multi fiber composite sand in dry wet circles, the unconfined compressive strength test was conducted on the basis of the orthogonal design scheme. Corresponding microcosmic mechanism was analyzed by scanning electron microscopy （SEM） test. Test results show that the influence of age and curing agent on the compressive strength of the composite solidified sand is maximum, the influence of number of cycles of wet and dry cycles is second. The amount of fiber and the amount of curing agent have a certain effect, the effect of fiber variety on unconfined compressive strength is the least. The effect is better when the fiber content is 0.45% and the curing agent content is 8%. The unconfined compressive strength of the solidified sand with fiber reinforced is significantly decreased with the increase of dry wet cycle times, 8% concrete and 0.45% modified polypropylene fiber is suggested.