加筋粉煤灰砂混合料大型三轴试验研究

为进一步研究粉煤灰砂混合料的性能,在不同固结和排水条件下对较优质量比例的粉煤灰砂混合料试样进行不加筋及复合加筋三轴试验。分析粉煤灰砂混合料试样在不同固结排水试验、不同筋材加筋和不同加筋层间距条件下的应力-应变性能。试验结果表明:在不固结不排水试验条件下,粉煤灰混合料抗剪性能最优;在加筋性能改善方面,轮胎加筋效果最佳,其次为三向土工格栅、双向土工格栅和格室加筋;随着加筋层间距减小,相应加筋效果系数增加,相应破坏时的主应力差值也不断增加,但加筋层间距不宜过小,20 cm时相应加筋性能较优。同时,随着围压增加,其破坏时的偏应力随之增加,相应的加筋效果会有所下降。上述结果揭示了加筋粉煤灰砂混合料三轴试验力学特性,可为粉煤灰砂混合料作为建筑回填材料和废弃物资源化应用提供理论依据。

Large-scale Triaxial Tests on Reinforced Fly Ash and Sand Mixture

Large-scale triaxial tests are conducted on sand specimens mixed with 20% fly ash under different consolidation and drainage conditions to investigate the behavior of fly ash and sand mixtures. The stress-strain behavior of fly ash and sand mixture with different reinforcements and different spacings between layers of reinforcement under different consolidation and drainage conditions is examined. Test results reveal that the shear performance of fly ash and sand mixture is the optimum under unconsolidated undrained condition. The effectiveness of tire reinforcement is the best,followed by triaxial geogrid,biaxial geogrid and geocell reinforcement. The corresponding coefficient of reinforcement effect and principal stress difference at failure both increase with the reducing of the spacing between reinforcement layers. Nevertheless,the spacing between reinforcement layers should not be too small; the reinforcement effect is good when the spacing is 20 cm. In addition, as confining pressure increases,the deviatoric stress at failure increases, while the corresponding reinforcement effect shrinks.The aforementioned results revealed the mechanical properties of reinforced fly ash-sand mixture under triaxial test, hence serving as theoretical basis for the application of fly ash-sand mixture.