基于冻融循环试验的改良泥水盾构浆渣劣化特性研究
Study on Deterioration Characteristics of Modified Slurry Shield Spoil Based on Freeze-thaw Cycle Test
张建勇1
作者信息
- 1. 中铁十四局集团大盾构工程有限公司,南京 211899
- 折叠
摘要
盾构隧道排放的渣土改性成路基材料可显著提高资源利用效率,但在反复冻融环境下存在安全隐患.依托武汉某盾构隧道工程,以大直径泥水盾构废弃浆渣为研究对象,通过添加自主研发的固废基胶凝剂(Cement-Slag-Gypsum-Alum,CSGA)及玄武岩纤维(BF)对盾构浆渣进行改良,并对CSGA-BF改良后的盾构浆渣开展冻融循环试验,研究不同纤维掺量、冻融循环次数等条件对改良盾构浆渣的外观劣化特性、力学特性及微观损伤机制的影响.结果表明:在冻融循环作用下,改良浆渣体积呈波浪式变化,并且整体表现为体积膨胀;随着冻融循环次数增加,改良盾构浆渣的无侧限抗压强度及弹性模量均呈现非线性递减,适当掺量的玄武岩纤维可增强筋-土界面的摩擦力,对浆渣的抗冻性具有重要作用,但纤维过量添加也会造成试样强度降低;当冻融循环达到9次后,改良盾构浆渣的抗压强度及弹性模量趋于稳定并且孔隙之间呈现贯通趋势.
Abstract
Modifying the muck discharged from a shield tunnel into subgrade material will significantly increase the utilization efficiency of resources,but the freeze-thaw conditions will create safety hazard.By using a shield tunnel of Heping Avenue in Wuhan as the example and using the spoil from large-diameter slurry shield as the study ob-ject,the shield spoil is modified by adding the independently developed waste solid based gelatinizer(Cement-Slag-Gypsum-Alum,CSGA)and basalt fiber(BF),and the shield spoil modified by CSGA-BF is subjected to freeze-thaw cycle test,in order to investigate how the parameters such as amount of basalt fiber and number of freeze-thaw cycles will affect the appearance deterioration characteristics,mechanical properties and microscopic damage mecha-nism of improved shield spoil.As the results indicate:Under the effect of freeze-thaw cycle,the volume of modified spoil changes in a wave-like pattern,and it generally exhibits volume expansion.As the number of freeze-thaw cycles increases,both the unconfined compressive strength and modulus of elasticity of the modified shield spoil decrease non-linearly.Adding a proper amount of basalt fiber will increase the friction at the reinforcement-soil interface,which is important to frost resistance of spoil.However,excessive amount of fiber will degrade the strength of the specimen.When the number of freeze-thaw cycles is 9,the compressive strength and modulus of elasticity of the modified shield spoil stabilize,and the pores become interconnected.
关键词
大直径泥水盾构/冻融循环/废弃浆渣/劣化机制Key words
Large-diameter slurry shield/Freeze-thaw cycle/Spoil/Deterioration mechanism引用本文复制引用
出版年
2024
NETL
NSTL
万方数据