One-half or more of the developing world's nonagricultural workers are employed in the underground informal sector, according to the International Labour Organization.
The dynamic equation of the transient response in a cracked rotor system was modelled, the numerical simulation solutions of the uncracked rotor and the cracked rotor were obtained.
The paper analyzes the occurrence regularity of rock burst of about 263 times in Laohutai mine field by database, the osculating relations of rock burst and active faults were summarized.