玄武岩纤维黄土抗剪强度变化规律与最优配合比分析

基于正交试验设计,进行固结不排水三轴(CU)试验,对试验结果进行极差和方差分析。并在控制含水率、压实度不变的条件下,研究玄武岩纤维黄土抗剪强度指标随纤维掺量的变化规律。结果表明:含水率、压实度、玄武岩纤维掺量、围压都是抗剪强度的显著影响因子;方差分析得到的局部最优配合比为含水率11%,压实度0.95,玄武岩纤维掺量0.4%;通过对最优配合比作进一步研究发现,黏聚力随纤维掺量的增加先增大后减小,当纤维掺量在0.4%左右时,黏聚力最大;纤维掺量为0.2%时,内摩擦角明显减小,纤维掺量为0.8%时,内摩擦角发生了较为显著的升高;其余的相差都不大,内摩擦角和掺量呈现上凹形曲线,实际工程中应控制纤维掺量不少于0.2%。

Experimental study on optimization of shear strength parameters of basalt fiber loess

Based on the orthogonal experimental design,the consolidated undrained triaxial(CU)test was carried out,and range and variance analysis were adopted to analyze the test results,the variation of shear strength index with the fiber content was studied while the water content and compaction degree remain constant.The results show that water content,compaction degree,basalt fiber content and confining pressure can significantly influence the shear strength.The local optimum mix ratio obtained by variance analysis is that water content accounts for 11%,compaction degree is 0.95 and the basalt fiber content is 0.4%.Further research on the optimal mix ratio found that the cohesive force increased first and then decreased with the increasing of fiber content.While the fiber content is about 0.4%,the cohesive force reached to maximum;while the fiber content is 0.2%,the internal friction angle is significantly reduced,as the fiber content is 0.8%,the internal friction angle increased significantly;and the variation of internal friction angle with the amount of the mixture shows a concave curve.In practical engineering,the fiber content should be no less than 0.2%.