摘要
为探索含石膏泥灰岩地层隧道喷射混凝土TSA侵蚀特性及防治对策,以山西省某高速公路隧道工程为依托,通过室内试验与现场试验,采用XRD+FTIR的组合测试方法,开展了隧道喷射混凝土TSA侵蚀试验分析研究。研究结果表明:该隧道衬砌混凝土腐蚀物中主要成分为碳硫硅钙石,即混凝土发生了碳硫硅钙石型硫酸盐侵蚀。根据施工时间、病害发育程度与发展规模,估测隧道衬砌混凝土TSA侵蚀出现在第18~36个月间。碳硫硅钙石型硫酸盐侵蚀对混凝土的力学性能影响较大,当碳硫硅钙石含量达到5.09%时,混凝土抗压强度耐蚀系数为86%,而抗折强度耐蚀系数仅为79%,即抗折强度损失对碳硫硅钙石型硫酸盐侵蚀更加敏感。通过采用玄武岩粗骨料和不含石灰粉的水泥可有效提高该隧道喷射混凝土的抗侵蚀性能。实际工程中,除物理及化学防护外,优化混凝土材料组成、提高混凝土施工质量、改善隧道结构防排水等可显著预防混凝土TSA侵蚀。研究成果可为类似地层隧道设计和施工及混凝土病害处治提供重要借鉴。
To explore the TSA erosion characteristics and control measures of the shotcrete in the gypsiferous marl stratum tunnel,based on a highway tunnel project in Shanxi Province,through indoor and field tests,this paper used the combination test of XRD + FTIR to carry out the experimental analysis of TSA erosion of the tunnel shotcrete.The analysis results showed that the main erosive ingredient of the tunnel lining concrete was the thaumasite,in other words,the concrete was corroded by carbonite sulfate.According to the construction time,disease developing degree,and developing scale,the TSA erosion of the tunnel lining concrete was estimated to occur in 18 to 36 months.The carbonite sulfate erosion has a great effect on the mechanical properties of the concrete,and the loss of flexural strength is more sensitive to the carbonite sulfate erosion.Using the basalt coarse aggregate and cement without lime powder can effectively improve the erosion resistance of the tunnel shotcrete.In practical engineering,besides the physical and chemical protection,optimizing the concrete material composition,and improving concrete construction quality and tunnel structure drainage can significantly prevent TSA erosion.The research results can provide an important reference for similar stratum tunnel design and construction,and concrete disease treatment.
作者
张亚军
ZHANG Ya-jun(Shanxi Road&Bridge Construction Group Co.,Ltd.,Taiyuan,Shanxi 030006,China)
出处
《山西交通科技》
2022年第4期99-104,共6页
Shanxi Science & Technology of Transportation
