Study on micro capsule self repair experiment of surrounding rock cracks in deep mining

In order to effectively prevent the roof falling and spalling, the gateway-roof balance structure instability and other major disaster accidents, a study idea with the micro capsules to repair the cracks in the sidewalls of the gateway was provided. Based on a similarity theorem, a self healing similar specimen with the micro capsules was designed and prepared. A uniaxial compressive test was conducted on the self healing similar specimen. With a multi level and multi factor orthogonal test, a study was conducted on the influence factors of the compressive strength for the specimen. With the calculation on the strength repair rate of the specimen, a study was conducted on the mixing amount, partical size, curing period, curing temperature of the micro capsule as well as the preloading affected to the self repair performances of the similar specimen. The test showed that as for the similar specimen with the micro capsules, the major influence factors and the influence degrees of the strength repair rate would be the mixed amount of the micro capsule > partical size of the micro capsule>curing period. The best combination of the self healing effect was the micro capsule with a mixed amount of 0.8%, the micro capsule with a partical size of 200 μm, the curing period of seven days and the curing temperature of 40 ℃.