The fundamental mechanisms controlling shear strength and deformability behavior of clay-fiber mixtures have still not been well established, nor the constraints that may affect their performance of shearing under different drainage conditions. This study aims to understand the behavior of a clay soil mixed with polypropylene fibers using results from drained and undrained triaxial compression tests, and to provide necessary calibration data for a shear strength prediction model. In drained tests, shear strength increased with fiber inclusion for a given mean effective stress, represented by an increase in apparent cohesion. In the undrained tests, the shear strength was not affected by pore water pressure generation. Results from the drained and undrained tests indicate that the fiber content had a greater influence on the apparent cohesion than on the friction angle. Drainage affected the improvement in the peak shear strength of fiber-reinforced soils, with superior improvement in the drained tests. As the percent improvement in shear strength decreased with increasing effective confining stresses for both tests, the difference in behavior in the drained and undrained tests was attributed to the strain at failure, with failure occurring at large strains in the drained tests but at smaller strains in the undrained tests.

控制粘土-纤维混合物剪切强度和变形行为的基本机制仍未完全确定，也没有确定可能影响其在不同排水条件下剪切性能的约束条件。本研究旨在利用排水和不排水三轴压缩试验的结果了解与聚丙烯纤维混合的粘土的行为，并为剪切强度预测模型提供必要的校准数据。在排水试验中，对于给定的平均有效应力，剪切强度随着纤维夹杂物的增加而增加，表现为表观内聚力的增加。在不排水试验中，剪切强度不受孔隙水压力产生的影响。排水和不排水试验的结果表明，纤维含量对表观内聚力的影响大于对摩擦角的影响。排水影响了纤维增强土的峰值剪切强度的提高，排水试验的改善效果显着。由于剪切强度的提高百分比随着有效围压的增加而降低，排水和不排水试验中的行为差异归因于失效应变，在排水试验中发生大应变时发生失效，但在排水试验中发生较小应变时不排水的测试。