新型高强经编复合土工织物拉伸特性测试方法

Tensile Test Method of a Warp-knitted Composite Geotextile

对一种由高模低缩涤纶长丝与丙纶短纤无纺土工织物采用经编工艺加工而成的高强经编复合土工织物进行了系列室内拉伸试验,分析了试样宽度、初始长度等因素对材料力学特性指标的影响,同时比较了宽条法和多肋法这2种不同计算方式得到的拉伸强度值的差异,为这种新材料的拉伸试验方法提供基础依据。试验成果表明:尽管复合织物具有类似土工格栅的加筋网格结构,但由于纵横向长丝与基层无纺织物依靠捆绑丝经编结合成整体,其拉伸强度的计算方法宜采用土工织物宽条法,而不能采用格栅肋条法计算。试样宽度越大,复合织物的拉伸强度越高,当试样宽度>100 mm时,强度基本趋于稳定。另外,试样初始长度的变化对拉伸强度影响不明显,长度增加,最大拉力仅略有降低,但延伸率明显减小,定应变5%对应的拉伸强度有较大提高。建议此类复合织物的拉伸试验宜采用200 mm宽条试样,且初始长度至少不低于300 mm。

A series of tensile test are carried out for a warp-knitted composite geotextile with high tensile strength composed with polyester filament and polypropylene non-woven geotextile.The effects of width and the initial length on the tensile properties of the geotextile specimen is studied,and furthermore,two different computing methods of tensile strength,wide-width strip method of geotextiles and multi-rib tensile method of geogrids,are compared.Test results show that the wide-width strip method is more suitable than multi-rib tensile method for the calculation of composite geotextile.The tensile strength of composite geotextile is higher with the increasing of specimen width.When the specimen’s width is greater than 100 mm,the strength tends to be stable proximately.In addition,the effect of the initial length of geotextile specimen is not obvious;with the increase of length,the maximum tension force is only slightly lower,but the elongation rate reduces greatly,and the tensile strength corresponding to an elongation rate of 5%is improved greatly.In the tensile test of such geotextiles,the width should be 200 mm,and the initial length should not be less than 300 mm at least.