土工格栅户外老化试验初步研究

作为一类特殊的高分子材料，土工合成材料越来越广泛地应用于水利、交通、环境工程等各个领域。在其服役期限内，能否保持一定的力学性能对整个工程的稳定性至关重要。研究高分子土工合成材料的老化性状，从而准确预测土工合成材料在各种环境条件下的使用寿命，已成为目前岩土工程的研究热点之一。在长江科学院土工合成材料户外老化试验基地开展了HDPE土工格栅的户外光氧老化试验。试验结果表明:在9个月内，土工格栅的拉伸强度基本保持不变甚至还有增高的趋势，这可能是由于高分子内部的二级反应补偿了紫外线的老化。紫外线提供了化学交联所需的能量，使得聚合物分子发生交联反应，轻微的收缩导致织物纤维被拉紧，使强度增大。这使得土工格栅强度在前期(9个月)得到一定程度的改善。9个月后，强度开始降低。本老化试验基地的远期研究成果可提供长时序土工合成材料老化性能物理力学指标的第一手资料。

Preliminary Study on Deterioration of HDPE Geogrid from Outdoor Exposure

As a special polymer material,geosynthetics is widely used in hydraulic,transportation and environmen-tal engineering.In its service period,the capability of maintaining mechanical properties is of vital importance to the stability of the whole project.The aging properties of geosynthetics are important for predicting the accurate life time of geosynthetics,which is a current hot research topic.Outdoor photo-oxygen aging test on HDPE geogrid was carried out at the outdoor test base of Yangtze River Scientific Research Institute.Test results showed that in the ini-tial 9 months,the tensile strength of geogrid remained unchanged or even increased due to secondary compensatory responses to the UV aging.UV provided required energy for chemical crosslinking,which resulted in the polymer crosslinking reaction and slight contraction in woven fabric.As a result,the tensile strength of geogrid increased in the initial period (9 months),but decreased after 9 months.The long-term research results of the test base could provide first-hand data for the physical and mechanical indexes of the aging properties of geogrid under outdoor ex-posure.