土工格栅施工损伤现场足尺试验研究

对两种不同规格型号的聚酯纤维单向土工格栅分别开展上设中粗砂保护层、上下均设保护层和无保护层 3 种工况的施工损伤现场足尺试验，共进行了 6 场试验，通过室内拉伸试验得到不同工况下格栅经施工损伤后的拉伸强度，给出了不同工况下格栅的施工损伤系数。通过对不同方式保护效果的对比分析，发现：在格栅上表面与粗颗粒填料间设置 10 cm 厚中粗砂保护层，对降低格栅筋材施工损伤程度以及提高其可用强度有明显效果；上设保护层和上、下均设保护层两种工况格栅的施工损伤系数较接近，说明格栅施工损伤主要源自上层填料的影响；填料粒径是影响格栅施工损伤程度的主要因素，而筋材自身技术规格的差异对施工损伤系数取值的影响较小。

Full-scale field tests on installation damage of geogrids

Six groups of full-scale field tests on installation damage of two kinds of PET uniaxial geogrid placed in gravel are performed.Geogrids are installed in three different manners,i.e.,directly in gravel,an additional sand layer above grids,additional sand layers both above and under grids,to simulate different installation conditions.Residual tensile strengths of geogrids exhumed after installation are tested,and installation damage factors are decided for grids under different working conditions.The effectiveness of sand layer for decreasing installation damage is assessed.The tests indicate that it is effective to place a 10 cm-thick sand layer over grids to decrease installation damage and increase the allowable tensile strength of grids.Reduction factors under two conditions with an additional sand layer are quite close,which reveals that the reduction of strength is mainly ascribed to the installation procedure of fill materials above grids.The level of installation damage depends mainly on the grain size of fill materials and parameters of compaction,and the difference of specifications of geogrids has rather small influence.