Many researchers have conducted laboratory studies for assessing the interaction mechanism of soil and geosynthetics and have shown that the performance of flexible pavement is enhanced by geosynthetic reinforcement through extending their service life or decreasing the base course thickness. However, there is a lack of comprehensive comparisons between different studies. This paper reviews laboratory studies available in the literature and presents a review of the main contributions. This literature review reveals that improvement of the performance due to the geosynthetic reinforcement relates to various factors and variables, including geogrid stiffness and geometry, geogrid location/depth, asphalt surface and aggregate thicknesses, and subgrade stiffness. Based on synthesizing laboratory testing studies, a regression-based formulation is proposed to predict the Granular Equivalent (GE) factor of geogrid reinforcement of flexible pavements. The predictive model is robust as it includes the key parameters mentioned above. This formula was developed from a regression analysis by back calculating the variety of the results of the performed experimental tests using the AASHTO1993 design method to evaluate the equivalent base course thickness of reinforced sections compared to unreinforced sections. The benefit of this study is realizing and understanding the structural benefits of geogrids and applying GE factors to a pavement design to reduce the thickness of gravel and/or asphalt and consequently extend the service life and reduce maintenance costs. It is expected that the appropriate use of geogrids can be a significant cost saving per project.

许多研究人员进行了实验室研究，以评估土壤与土工合成材料之间的相互作用机理，并表明，通过延长使用寿命或减小基层厚度，土工合成材料增强了柔性路面的性能。但是，不同研究之间缺乏全面的比较。本文回顾了文献中提供的实验室研究，并对主要贡献进行了回顾。该文献综述表明，由于土工合成材料的增强，性能的提高与各种因素和变量有关，包括土工格栅的刚度和几何形状，土工格栅的位置/深度，沥青表面和集料厚度以及路基刚度。根据综合的实验室测试研究，提出了一种基于回归的公式来预测柔性路面土工格栅加固的颗粒当量（GE）因子。预测模型是鲁棒的，因为它包含上述关键参数。通过使用AASHTO1993设计方法反算所进行的实验测试的结果的多样性，通过回归分析来开发该公式，以评估与未增强段相比增强段的等效基层厚度。这项研究的好处是认识并了解土工格栅的结构优势，并将GE因素应用于路面设计中，以减少砾石和/或沥青的厚度，从而延长使用寿命并降低维护成本。预计适当使用土工格栅可以为每个项目节省大量成本。