Durability of concrete shaft wall has seriously endangered the safety of mining in salt environment. Based on the background of Tongting Coal Mine project, the corrosion behavior of concrete under structural loads was studied. In order to simulate the practice of shaft lining concrete, accelerated corrosion of concrete tests are adopted to simulate the real corrosion environment of concrete, and using the ultrasonic detection method, which could obtain the evolution law of the corrosion thickness of concrete by the time. Through micro structure images, quantitative explication of concrete corrosion thickness is analyzed. Compared with the experimental results, the factors of concrete corrosion are discussed.
The shaft wall is the guarantee of the mine safety produces. Since 1990s, the reinforcement layer and initial shaft lining emerge a large number of water seepage in Tongting Coal Mine, bedrock section wall also appeared some outlet points. The circumferential length through the water takes 112 to 113 of borehole wall circumference. Under the long-term water erosion, the well wall concrete present expansion destruction, loss of its strength, and even induce concrete peeling, which not only have a dangerous for personnel and equipment, shaft wall safety is also worrying.
Non-destructive testing technique of concrete is an effective way for quantitative measurement its structure, widely used in the healthy monitoring and condition assessment of existing concrete macro/micro structures. As one of the most important aspects of ultrasonic monitoring, it has the good direction, strong penetrability, high energy conversion, and reflection, refraction and wave conversion when meet damage interface of corrosion concrete, harmless to the human body, strong adapt ability, high sensitivity, light equipment, flexible use, speed inspection, so it has particularly unique advantages in the field of nondestructive testing (Liang & Mu 2005, Lin 2002). This paper is aim to study corrosion characteristics of concrete shaft lining by ultrasonic detection in salt environment, simulating the shaft concrete experienced in coal mining.