Guangsi Zhao

Long-Term Field Monitoring of Additional Strain of Vertical Shaft Linings in East China

The vertical additional force (VAF) is the fundamental cause of the rupture of hundreds of vertical shaft linings (VSL) in East China, long-term monitoring of additional strain which caused by VAF is conducive to well control the performance of VSL during operating, curing and after treatment. Based on long year filed monitoring results, the long-term strain of VSL can be separated into temperature strain and additional strain, and the former varies sinusoidal with the seasonal temperature, while the latter shows a linear cumulative. The cumulative rate of vertical strain accelerates when VSL are on the verge of rupture, and followed by suddenly decrease in the process of crack. The strain monitoring system can also be used to control the process of stratum-grouting as an electronic eye, and the mechanism of curing the rupture of VSL is that the VAF could be not only released but also restrained by cement grouting. Furthermore, the time of rupture can be predicted based on the long-term strain monitoring data, for example, by R/S method. The suggested methods here can be used for preventing and curing rupture of VSL in other similar mines.