【作者】 郑鸿；

【导师】 刘光烨；

【作者基本信息】 青岛科技大学 ， 材料加工工程， 2005， 硕士

【摘要】 本文以拉伸土工格栅为主要研究对象,从拉伸土工格栅的加工特点入手,对其力学性能、蠕变性能、铺设损伤特性等影响产品工程应用设计强度的主要因素,进行了较系统地研究: 为研究冲孔参数和拉伸参数对拉伸土工格栅力学性能的影响,选用不同规格尺寸的冲头,调节拉伸温度、拉伸速率、拉伸比等参数对土工格栅的拉伸工艺进行模拟,对制得的格栅样片进行力学性能测试,分析各参数对拉伸土工格栅力学性能的影响规律。发现在一定范围内,随着拉伸温度的降低,或随着拉伸速率、拉伸比的提高,格栅的拉伸强度先增大后降低,而延伸率逐渐降低,2%和5%延伸率时的强度逐渐升高;拉伸温度和拉伸速度以及拉伸比对于格栅的力学性能具有相似的影响规律。 通过对试样肋条部位结构的DSC分析,发现拉伸工艺参数不同,肋条部位的结晶度不同,且拉伸后试样的结晶度均比未拉伸时有所提高;较低拉伸温度下与较高拉伸速率下试样的结晶度相近,表明各拉伸参数之间具有一定的关联性。 设计系统的蠕变实验对拉伸土工格栅的蠕变特性进行研究,并对土工格栅的蠕变曲线进行方程模拟,发现三次多项式方程可以很好地拟合其蠕变特性;同时,对不同温度、不同负荷下试样的蠕变行为进行分析,并测得EGRB系列拉伸土工格栅产品的蠕变折减因子。 在5种填料级配和3种压实条件下,对EGR系列拉伸土工格栅进行现场破坏实验,系统地研究拉伸土工格栅的铺设损伤特性,并测得适用于工程设计的EGR系列格栅产品的铺设损伤因子。更多还原

【Abstract】 The stretched geogrid was chosen as the major object studied in this paper. The properties of the geogrids, including the mechanical properties, the creep properties, installation damage, were systemically investigated, which significantly affect the design strength of geogrids for engineering application.Various punchers of different sizes were chosen for the test of the mechanical properties, in which the draw temperature, draw speed, draw ratio were designed, in order to study the effects of punching and stretching technical factors on mechanical properties of geogrids. And then the processing was simulated. It is shown that, the tensile strength increases firstly and then decreases, while the elongation continuously decreases and the strength at 2% and 5% elongation continuously increases, with the draw temperature decreasing, or the draw speed, the draw ratio increasing. It seems that there are similar regulations between the effect of the draw temperature, the draw speed and the draw ratio on the mechanical properties of the geogrids.DSC results show that crystallinity of the geogrids ribs is different owing to various stretching technical factors, and that the crystallinity of the stretched sample is larger than the unstretched one. The crystallinities of the sample are similar at lower draw temperature and higher draw speed, which show that there is correlation among the stretching factors.The systematic experiments were designed in order to study the creep properties of stretched geogrids. And the creep equations were simulated with the creep curves of geogrids. It is shown that the cubic polynomial equations are best in the simulation of the creep properties of the geogrids. The creep behaviors of the geogrids were systematically studied with different temperature and load, with the creep reduction factors for EGRB stretched geogrids determined.The full-scale site damage tests of EGR geogrids were performed, with five kinds of grading fill materials and three types of compaction conditions. The installation damage properties of stretched geogrids were systematically. As a result, the site damage factors were determined applying to EGR geogrids for engineering design.更多还原