酸性环境对固化盾构渣土的侵蚀性能及机理研究  

Erosion Performance and Mechanism of Cured Shield Muck in Acidic Environment

作　　者：张恒根 李海峰[1] 邓声贵[2] 刘涛[1,3] ZHANG Henggen;LI Haifeng;DENG Shenggui;LIU Tao(Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering,Ocean University of China,Qingdao 266100,Shandong,China;School of Marine Earth Sciences,Ocean University of China,Qingdao 266100,Shandong,China;Laboratory for Marine Geology,Qingdao Marine Science and Technology Center,Qingdao 266237,Shandong,China)

机构地区：[1]中国海洋大学海洋环境与地质工程山东省重点试验室,山东青岛266100 [2]中国海洋大学海洋地球科学学院,山东青岛266100 [3]青岛海洋科技中心海洋地质过程与环境功能试验室,山东青岛266237

出　　处：《隧道建设(中英文)》2024年第S2期256-265,共10页Tunnel Construction

基　　金：国家自然科学基金资助项目(42277139,U2006213);中央高校基本科研业务费专项(202261062)。

摘　　要：为研究酸性水化学环境对路用水泥基固化盾构渣土材料的侵蚀作用及机理,首先,采用一种新型早强型水泥基材料(ESCA)和普通硅酸盐水泥(P·O 42.5)2种固化剂对来自芜湖市城南过江隧道工程的盾构渣土进行固化,并进行室内固化试验;然后,配制4种pH值分别为7、5、3、1的水溶液对2种固化渣土试样进行45 d的浸泡,并对比测试试样的物理性质(质量和纵波波速)和力学性质(无侧限抗压强度);最后,采用扫描电镜(scanning electron microscope,SEM)和工业CT(computed tomography)系统研究酸性侵蚀对固化渣土微观结构的损伤劣化机理。结果表明:1)在经过45 d的酸浸试验后,ESCA型和P·O 42.5型固化渣土的承载结构均有不同程度的劣化,浸泡溶液pH=1时2种固化渣土的强度分别下降65.61%和72.25%;2)浸泡溶液pH值的降低会使2种固化渣土试样的塑性变形增大,在pH=3时2种固化渣土试样均表现出由劈裂破坏向剪切破坏转变的趋势;3)相比P·O 42.5型固化渣土,ESCA型固化渣土酸侵蚀后的孔隙发育较少,拥有更好的耐酸腐蚀能力。In this study,the erosive effects and mechanisms of acidic water-chemical environments on road-use cement-based cured shield muck materials are investigated.First,indoor curing experiments are carried out on shield muck produced from the Chengnan river-crossing tunnel in Wuhu,China,using two curing agents,a new type of early-strengthening cement-based material(ESCA)and ordinary Portland cement 42.5(P·O 42.5).Then,four aqueous solutions with pH values of 7,5,3,and 1 are prepared to soak the two cured muck specimens for a period of 45 days,and the specimens are comparatively tested for physical(mass and longitudinal wave velocity)and mechanical properties(unconfined compressive strength).Finally,scanning electron microscope and industrial computed tomography system are used to investigate the damage and deterioration mechanism of acid erosion on the microstructure of cured muck.The results show that:(1)The bearing structures of both ESCA-type and P·O 42.5-type cured specimens are deteriorated to different degrees after 45 days of acid leaching tests,and the strength of the two cured specimens decreases by 65.61%and 72.25%at pH=1 of the leaching solution,respectively.(2)The decrease of the pH value of the soaking solution increases the plastic deformation characteristics of the two types of cured muck specimens,and both types of cured muck specimens show a tendency to change from cleavage damage to shear damage at pH=3.(3)Compared with the P·O 42.5-type of cured muck specimens,the ESCA-type of cured muck specimens has less pore development after acid attack,and possesses a better ability to withstand acid corrosion.

关 键 词：固化盾构渣土 酸性侵蚀 固化试验 损伤劣化机理 CT扫描 

分 类 号：U45[建筑科学—桥梁与隧道工程]