纤维与粉煤灰改良粉土的正交试验分析

Orthogonal Test Analysis of Improved Silt with Fiber and Fly Ash

黄河三角洲地区粉土、粉砂分布广泛,为了使其满足作为路基填土等实际工程的要求,消除不良工程特性而需要对其进行改良。掺入适量的粉煤灰、石灰可以提高粉土的抗剪强度,但同时也会增加土的脆性。因此在改良土中掺入纤维来进一步提高其抗剪强度并改善其脆性。采用正交试验设计,选取了具有典型代表意义的九组试样进行三轴压缩试验、直接剪切试验与固结试验,分析了不同粉煤灰、石灰掺量,纤维掺量与纤维长度对改良土的抗剪强度与压缩性等工程特性的影响。获得了各项指标的粉煤灰与石灰掺量、纤维掺量与纤维长度的最佳配合比参考值。采用线性多元回归方法,建立了改良土力学指标与多种影响因素的经验公式,为黄河三角洲地区粉土的改良提供了可以借鉴的数据与经验。

Silt, silty sand is widely distributed in Yellow River Delta. In order to meet the requirements of the actual project such as roadbed fill and eliminate undesirable engineering characteristics, it is necessary to improve silt’s engineering characteristics. The appropriate amount of fly ash and lime can improve the shear strength of silt, but also increase the soil brittleness. So that the fiber is incorporated into the improved soil to further improve its shear strength and improve its brittleness. Orthogonal experimental design was used, nine groups of specimens with typical representative significance were selected to conduct triaxial compression tests, direct shear tests and consolidation tests. The effects of different fly ash, lime content, fiber content and fiber length on the shear strength and compressibility of the improved soil were analyzed. The best reference ratio of fly ash and lime content, fiber content and fiber length of various indicators was obtained. The empirical formula of improved soil mechanics index and various influencing factors was established by linear multiple regression method, which provides reference data and experience for the improvement of silt in Yellow River Delta.