Classification grading evaluation index system and evaluation method of surrounding rock for full section shaft boring machine

In view of the instability and collapse of weak or broken surrounding rock, hard rock is difficult to break, formation water gushing, fault joints and other engineering problems caused by the complexity of formation. The classification index system and evaluation method of surrounding rock were studied. The independence and correlation of each factor under the interaction of “rock” and “machine” are considered. The classification index system and evaluation method of surrounding rock are established. A comprehensive identification method of stratum adaptability for borehole sinking by for full section shaft boring machine is proposed. First, based on the characteristics of full section shaft boring machine sinking technology, analysis of the formation problems faced by the shaft boring machine sinking and prevention and control measures. Based on the influence of rock mechanics characteristics of surrounding rock, rock breaking ability of equipment, rock structure characteristics, mutual support of surrounding rock and equipment, and water prevention and control of stratum under the interaction of rock-machine, the selection principle of surrounding rock classification index is put forward. Three criteria, namely, rock cuttability, surrounding rock self-stability and water control, are constructed, as well as 13 basic evaluation index system frames. The weight value of surrounding rock classification index system is determined, and the basic index is quantified by fuzzy comprehensive evaluation and percentage system. The mathematical model of multi-dimensional matrix structure surrounding rock classification and evaluation is established. According to the calculation and analysis, the influence of rock cutting ability, surrounding rock self-stability and stratum water-controlling ability on the shaft drilling machine can be divided into 5 categories: favorable, generally favorable, moderate, unfavorable and very unfavorable. According to the calculation results, the surrounding rock conditions of the shaft excavation machine can be divided into Ⅰ-Ⅴ categories. The adaptability between drilling and formation adaptability of full-section vertical shaft boring machine is evaluated. The control measures of surrounding rock for full section shaft boring machine are put forward. The feasibility and rationality of surrounding rock classification index system and evaluation method are verified by taking the sinking project of the first full-section vertical shaft boring machine with guide shaft in China as an example. The classification index system and evaluation method of surrounding rock of full-section vertical shaft boring machine can provide scientific basis for the formulation and implementation of technical schemes of rock breaking tunneling, disaster prevention and control, surrounding rock stability control and so on.