A fuzzy logic model to predict the specific power of rock fragmentation for large-diameter shaft rigs rolling cutters

In the excavating shafts projects, to predict the project period and cost through evaluating performance of the large-diameter shaft rigs (LDSRs) are required. The evaluating error could lead to the period delay and the budget over spend. The main means of evaluating LDSRs´ performance are to evaluate their ability of rock fragmentation and drilling rate and operation efficiency. The specific power of rock fragmentation is one of main performance parameters of the rolling cutters with kentanium teeth. It is used to determine LDSRs´ performance parameters and evaluate LDSRs´ performance. The model of specific power of rock fragmentation has been analyzed in this paper. Fuzzy logic method (FLM) has been introduced into the prediction of the specific power of the rock fragmentation. As input variables of fuzzy logic method, rolling cutters structure dimension and rock mechanic performance and drilling technique three-types include nine-kind parameters which are interrelated with specific power of rock fragmentation have been determined. The fuzzy logic model to predict specific power of rock fragmentation of LDSRs´ rolling cutters has been established. Under given input variables circumstances, the model can predict effectively specific power of rock fragmentation of LDSRs´ rolling cutters. The comparison of the drilling shaft practice real value and model value shows that the model values are close to the drilling shaft practice real values. This indicates that the model is reasonable and fuzzy if-then rules can express the experience of the drilling shaft practice. Using this model value, the period and cost of the excavating shafts project can be predicted precisely. At same time, the model value can be used to guide the design of the rolling cutters and LDSRs and drilling technique parameters.