HDPE土工膜端部张拉力的大规模实测数据分析

ANALYSIS OF RESULTS OF LARGE-SCALE TESTS ON TENSILE FORCE OF HDPE GEOMEMBRANE PLACED ON SIDE SLOPE IN LANDFILL

垃圾填埋场边土工膜主要受到温度应力和垃圾压缩引起的张拉力的作用,为评价垃圾填埋场防渗系统中高密度聚乙烯(HDPE)土工膜的温度应力和垃圾填埋压缩引起的端部张拉力,以短纤维无纺布、HDPE土工膜组成防渗系统,进行大规模现场试验。试验结果表明:伴随环境温度的下降,HDPE土工膜中产生温度应力,当填埋高度较小时作用在HDPE土工膜端部的张拉力主要为温度应力;随着填埋高度的增加,压缩引起的HDPE土工膜端部张拉力增大。用有限元算法对压缩引起的端部张拉力进行分析,并采用温度与HDPE土工膜张拉力的关系对温度应力进行分析。计算结果与实测结果的对比情况表明,考虑填埋压缩引起的张拉力的应力松弛后计算结果更加接近实测结果。

The forces at the shoulder of geomembrane placed on the side slope as liner system in landfill are mainly temperature stress and tensile force due to waste compaction. In order to evaluate the temperature stress and tensile forces of high density polyethylene(HDPE) geomembrane in the liner system,which is composed of HDPE geomembrane and non-woven geotextile,the large-scale tests were conducted. The results show that the temperature stress within the HDPE geomembrane occurs with decrease of circumstantial temperature;the tensile force at the shoulder of HDPE geomembrane is mainly temperature stress when the height of soil is low;the tensile force of HDPE geomembrane by compaction work increases with the increase of height of soil. The tensile forces of HDPE geomembrane due to waste compaction are analyzed by finite element method;and the temperature stresses are analyzed by the relationship between temperature and the stress,the comparison shows that the calculation results considering stress relaxation of tensile force are closer to the test values.