侧限荷载和温度对PE-HD土工格栅蠕变特性的影响

摘要

采用能同时研究温度和侧限荷载对土工格栅蠕变特性影响的自制设备，研究了温度和侧限荷载对高密度聚乙烯(PE-HD)土工格栅蠕变特性的影响，并采用相关性分析方法进行了分析。结果表明，在低荷载水平(拉伸强度的20%)条件下，温度和侧限荷载对土工格栅的蠕变特性影响显著。土工格栅的蠕变应变随土工格栅温度的增加而显著增大。当温度为25℃时，在侧限荷载分别为0，50，100 kPa条件下，土工格栅的最终蠕变应变比15℃时分别增大67%，77%，58%；当温度为35℃时，在侧限荷载分别为0，50，100 kPa条件下，土工格栅的最终蠕变应变比25℃时分别增大34%，35%，22%。蠕变应变随土工格栅所受侧限荷载的增加而显著减小。在侧限荷载为50 kPa条件下，土工格栅在15，25，35℃时的最终蠕变应变比无侧限荷载时减小19%，14%，14%；在侧限荷载为100 kPa条件下，土工格栅在15，25，35℃时的最终蠕变应变比侧限荷载为50 kPa时减小9%，18%，26%。对土工格栅蠕变应变与时间对数曲线进行线性拟合，拟合度大于0.9。温度、侧限荷载对土工格栅蠕变应变的相关性分别为0.735，-0.643，土工格栅温度对土工格栅蠕变应变的影响程度大于侧限荷载。%A new geogrids creep test equipment was designed to perform creep tests under confined load and temperature simultaneously,the influence of the confined load and temperature on the creep characteristics of high density polyethylene(PE-HD) geogrids was studied,the test data was dealt by correlation analysis. The results show that the effect of temperature and confined load on geogrids creep are obvious under the low load level(20%tensile strength). the geogrids creep increases significantly with the temperature increases. At the temperature of 25℃,the final creep strains of geogrids under the conditions that the confined loads are 0, 50,100 kPa increase by 67%,77%,58%respectively comparing with that at the temperature of 15℃. At the temperature of 35℃,the final creep strains of geogrids under the conditions that confined loads are 0,50,100 kPa increase by 34%,35%,22%respectively comparing with that at the temperature of 25℃. The creep strains decrease significantly with the confined loads increase. Under the condition that the confined load is 50 kPa,the final creep strains of geogrids at the temperature of 15,25,35℃decrease by 19%, 14%,14%respectively comparing with that under no confined load. Under the condition that the confined load is 100 kPa,the final creep strains of geogrids at the temperature of 15,25,35℃decrease by 9%,18%,26%respectively comparing with that under the condition that the confined load is 50 kPa. The relationship between geogrids creep and the logarithm of time is linearly fitted,the degree of fitting is more than 0.9. The influences of the temperature and the confined load on the geogrids creep are 0.735 and-0.643 respectively. The influence of the temperature is greater than the influence of the confined load.