白云岩层中硬石膏岩对隧道结构危害机制研究

Research on mechanism of damage of anhydrock in dolomite layer to tunnel structure

以杭兰公路宜巴段白云岩层中不规则发育的硬石膏岩为研究对象,采用X-衍射试验、离子色谱分析、环境扫描电镜及能谱分析等试验手段,定量研究硬石膏岩对隧道结构的危害。研究结果表明,硬石膏岩对隧道结构的危害主要表现在其水化膨胀作用、溶蚀产生的硫酸盐侵蚀及其溶出的酸性环境对白云岩溶蚀的加剧作用。在此基础上,结合区域工程地质条件,提出硬石膏岩及其与白云岩耦合溶蚀作用下的隧道混凝土防护结构劣化机制。给出以降低地下水水位及提高混凝土性能为主的类似工程治理建议。

Taking the irregular developed anhydrock in dolomite layer of Yi-Ba section which located in Hangzhou-Lanzhou highway as research object,and adopting test methods such as X-ray diffraction experiment,ion-chromatographic analysis,environmental scanning electron microscopy and energy spectrum analysis tests,it is mainly quantitatively analyzed the damage of anhydrock to the tunnel structure.The result shows that the damage to the tunnel structure mainly displayed in hydration-swelling action,sulfate erosion generated by corrosion and the aggravation of dolomite corrosion by acid environment.On this basis,combining with regional engineering geological condition of this area,this paper proposes the deterioration mechanism of the tunnel concrete protective structure under anhydrock and the coupled corrosion action of the anhydrock and dolomite.Finally,it gives treatment suggestions for the similar engineering,mainly by lowering the groundwater level and improving the performance of the concrete.