中文摘要：

在聚对苯二甲酸乙二醇酯（PET）焊接土工格栅的基础上，设计了不同形式的土工格栅，通过三轴剪切试验研究了不同形式土工格栅加筋砂的强度及破坏形态，分析了单向土工格栅横肋间距对加筋砂强度的影响，探讨了格栅基本单元内部筋材布置形式对加筋砂强度的影响．结果表明，不同形式的土工格栅具有不同的加筋效果．其中：多向土工格栅的加筋效果最佳，但材料用量最多，为土工格栅基本单元的2．21倍；双向土工格栅的加筋效果优于单向和三向土工格栅；单向土工格栅在低围压下的加筋效果比三向土工格栅的好，而在高围压下的加筋效果比三向土工格栅的差，且其加筋效果随着横肋间距的减小而增强；单向土工格栅的良好加筋效果主要体现于提高加筋砂的黏聚力，而双向、三向和多向土工格栅的良好加筋效果主要体现在于提高加筋砂的内摩擦角．

英文摘要：

Based on the polyester welded biaxial geogrid （PET25-25）, different forms of geogrid were de- signed, such as uniaxial, biaxial, triaxial and multiaxial ones. By means of triaxial compression tests, the strength property and failure modes of these forms were obtained. Besides, the influence of the space be- tween transverse ribs in uniaxial geogrid on the strength and the configuration of reinforcement inside the basic geogrid element were studied. It can be seen from the test results that different forms of geogrid had different reinforcing effects~ the multiaxial geogrid had the best reinforcing effect, consuming the greatest amount of material, 2.21 times of the basic geogrid element~ biaxial geogrids performed better in reinfor- cing than uniaxial and triaxial ones~ the comparison of uniaxial geogrids and triaxial ones were different in different confining pressures, that is, in low confining pressure, uniaxial geogrids performed better than triaxial ones, in contrast, in high confining pressure, triaxial ones did better. In addition, the reinforeing effect of uniaxial geogrids inereased with the space of transverse rib decreasing; uniaxial geogrids mainly improved the cohesion of reinforced sand, however, other forms of geogrid mainly increased the friction angle.