清洗后的劣化道砟直剪力学特性分析

摘要

为探究劣化道砟力学特性及其循环利用机理,分别针对清洗后掺加不同比例新道砟的劣化道砟,结合洛杉矶磨耗试验仪和应变控制式直剪仪,开展了不同比例新旧道砟混合体的直剪试验,探讨了不同垂压(50、100、200 kPa)下不同比例新旧道砟混合体应力应变特征.研究结果表明:劣化道砟抗剪强度随新道砟含量增多而增大,如100 kPa垂压下,新道砟含量为50％和100％的样本抗剪强度分别为143.4 kPa和176.7 kPa,比劣化道砟抗剪强度分别提高了24.0％和52.9％;劣化道砟剪胀现象随新道砟含量增多而越不明显,如100 kPa垂压下,新道砟含量为50％和100％的样本最大剪胀量分别为9.842 mm和7.969 mm,比劣化道砟最大剪胀量分别降低了25.8％和39.9％;清洗后劣化道砟力学性能与新道砟差别较小,在一定条件下可与新道砟混合重复使用.%In order to study the mechanical characteristics and reuse of a washed recycled ballast,a Los Angeles abrasion tester and strain-controlled direct shear apparatus were used in experiments to investigate the stress-strain characteristics of recycled ballast with different proportions of fresh ballast under different normal stresses (50,100,and 200 kPa).Based on the experimental results,the mechanical features of the ballast were discussed.The results show that ballast strength increased with the proportion of fresh ballast.The strength of mixtures with 50％ and 100％ fresh ballast were 143.4 and 176.7 kPa,respectively,under normal stress of 100 kPa;an increase of 24.0％ and 52.9％,respectively,compared to pure recycled ballast.The shear dilatation of the mixture also increased with the proportion of fresh ballast.For 50％ and 100％ fresh ballast samples,the values are 9.842 mm and 7.969 mm,respectively,under normal stress of 100 kPa;a decrease of 25.8％ and 39.9％,respectively,compared to pure recycled ballast.There was a small difference in mechanical characteristics between washed recycled ballast and fresh ballast,and the washed recycled ballast can be reused with fresh ballast under certain conditions.