冻融循环对塑料土工格栅拉伸性能的影响  

Freezing-Thawing Cycle Effect on the Tensile Properties of Polyethylene Plastic Geogrids

作　　者：汪恩良[1] 徐学燕[1] 常俊德 钟华 高占坤 

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090 [2]黑龙江省水利科学研究院,黑龙江哈尔滨150080

出　　处：《冰川冻土》2008年第4期646-651,共6页Journal of Glaciology and Geocryology

基　　金：黑龙江省青年基金项目(QC04C04)资助

摘　　要：在-25^+25℃环境温度条件下,采用水中冻融和空气中冻融两种方式,经过50次冻融循环后,在15℃、0℃、-10℃、-20℃和-35℃工况下对土工格栅试样进行了拉伸性能的试验研究,获得了聚乙烯塑料土工格栅的极限承载力、最大延伸率、不同延伸率对应的应力值等数据.试验结果表明,聚乙烯塑料土工格栅在低温时抗拉性能明显提高,从+15℃降至-35℃时,5%延伸率对应的抗拉强度提高107%,极限承载力提高19%.同时,聚乙烯塑料土工格栅极限延伸率随温度降低呈线形关系降低,从+15℃降至-35℃时,极限延伸率降低80%.The retaining ethylene plastic geogrids wall reinforced with Polyis experienced many freezing-thawing cycles in seasonal frozen regions. The reinforced material works in the condition of temperature alternation, sometimes higher and sometimes lower than the freezing point. So whether the geogrids work normally should be studied by experiments. A number of freezing-thawing tests were taken in laboratory with the temperature between 25℃ and - 25 ℃. The freezing-- thawing cycle tests were taken in two modes, in water and in air. The geogrids were experienced 50 freezing --thawing cycles. The tensile tests were taken at the temperature of 15 ℃, 0℃, -10℃, -20℃ and -35℃. Through the experimental research on the tensile properties of geogrids, the ultimate bearing capacity, maximum extensibility and stress for different extensibility of geogrids were obtained. The test results show that at lower temperature the tensile properties of geogrids increase obviously. The tensile strength responding to 5% extensibility increases 107 %, and the ultimate bearing strength increases 19%, when the temperature drops from 15℃ to -35 ℃. With the falling of temperature, the ultimate extensibility of polyethylene plastic geogrids reduces linearly. The ultimate extensibility reduces 80% when the temperature drops from 15 ℃ to -35 ℃, from which it can be seen that the bearing strength of geogrids increases obviously in lower temperature. So the tensile strength responding to 5% extensibility should be taken as the design strength. However, the creep characteristics should be considered also, when the geogrids are used in repeatedly freezing-- thawing conditions.

关 键 词：聚乙烯塑料土工格栅 冻融循环 拉伸试验 力学特性 

分 类 号：TU502.6[建筑科学—建筑技术科学]