深部富水岩层中混凝土衬砌腐蚀破坏机理分析

Mechanism analysis of corrosion failure of concrete lining structure in deep water-rich rock layer

混凝土衬砌结构是地下资源开采中普遍采用的支护结构形式,其在地下水腐蚀作用下易发生粉化甚至失去承载能力,严重威胁地下工程的安全。以某矿建井筒垂深603~620 m的腐蚀粉化段的混凝土衬砌结构为研究对象进行了XRF和XRD检测,并分析了混凝土的腐蚀机理,提出了相应的治理措施。试验结果表明:地下水中的SO_(4)^(2-)、Mg^(2+)等离子对混凝土衬砌的腐蚀作用是造成井壁粉化和破坏的重要原因;混凝土的腐蚀是由表及里的腐蚀发展过程,脱落及松散体的CaO流失严重,松散的原因在于胶结物的流失,且造成了钢筋一定程度的锈蚀;腐蚀轻微或未腐蚀区域可采用注浆、引流(截水)、改善井壁混凝土的抗侵蚀特性和加固相结合的方法进行治理,而腐蚀严重区域需要开槽重塑。

Concrete lining structure is a common form of supporting structure in the exploitation of underground resources. It is easy to pulverize or even lose its bearing capacity under the action of groundwater corrosion, which seriously threatens the safety of underground engineering. Taking the concrete lining structure of the corroded and pulverized section of a mine shaft with a vertical depth of 603~620 m as the research object, XRF and XRD detection and analysis were carried out, and the corrosion mechanism of the concrete was analyzed, and the corresponding treatment measures were proposed. The test results show that the corrosion effect of SO_(4)^(2-) and Mg^(2+) plasma in groundwater on concrete lining is an important reason for the pulverization and damage of shaft lining, and the corrosion of concrete is the corrosion development process from the surface to the inside, and the CaO loss of shedding and loose body is serious, and the loose reason lies in the passing of cement and the corrosion of steel bar to a certain extent. The areas with slight or uncorroded corrosion can be treated by the combination of grouting, drainage (water interception), improving the corrosion resistance of sidewall concrete and reinforcement, while the areas with serious corrosion need to be slotted and reshaped.