The Blasting Parameter Optimization And Effect Evaluation Of Rock Roadway

During the blasting drivage of rock tunnel,the traditional blasting technique,on the conditios of relatively small the tunnel cross-section and considerable clamping action,will lead to the enormous over-break or under-break of excavation,and the enlarge disturbed surrounding rock area,make the support difficulty and support costs increasing,affect both the quality of construction and the construction schedule.Due to these,based on the rock tunneling experimental research of Dading Mountain mining of Sichuan Jinning mines Co.,Ltd.,this paper carried out the research on rock blasting parameter optimization and blasting effect evaluation.And research has a certain reference value for improving the similar mine rock tunneling blasting effect,raising the tunneling efficiency,increasing support effectiveness and reducing support costs.According to the situation of Dading Mountain mine,the rock roadway blasting designs were developed for different roadways,and also blasting experiments and blasting effect evaluation were carried out.Achieved results were as the following:(1)After each burst test,statistics of the rock pile sizes,overbreak location and overbreak range were collected.With the analysis of the large pieces features and the artillery holes utilization,the optimized blasting parameters were obtained on the basis of burst test.(2)Blasting vibration test was carried out at the same of tunneling blasting.According to the test,it was found that,the vertical vibration velocity was significantly greater than the level,when the measuring point is on the explosion source and in close the explosion source;When measuring point is paralleled the explosion source and on the explosion source and,horizontal vibration velocity was significantly greater than the vertical vibration velocity;when the dosing and distance were same,the vertical and horizontal vibration velocity of on the explosion source are significantly greater than that of paralleled the explosion source.(3)According to the rock roadway burst test statistics,make the blasting effect index for the reference sequence,make the blasting design parametersfor comparative sequence.results that the maximum gray correlation of affect average overbreak amount is the number of auxiliary holes;the greatest impact max overbreak amount is surrounding pitch;the greatest impact max underbreak amount is the number of auxiliary hole;the greatest impact retention half hole rate is the dosage of auxiliary holes;the greatest impact the length of explosion heap is the dosage of undercutting holes.Impact the entire blasting effect parameters is the dosage of surrounding holes?the number of undercutting holes and the dosage of undercutting holes.(4)The model of prediction blasting effect was established with BP neural network,prediction results were relatively close to the actual results.According to the prediction by BP neural network,blasting parameters were repeatedly adjusted,the most economical and practical blasting parameters were obtained with ensuring blasting effect for Dading Mountain mine.(5)Based on the grey correlation analysis of the blasting parameters,It was more comprehensive analysis for all factors affecting tunnel blasting effects by using AHP.It was indicated that the rock nature and pore network parameters was the main affecting parameters in first-level indicators;Rock strength,reasonable degree of fissures,pore density coefficient and coupling coefficient were greater impact indicators in the second-level indicators.(6)It's established the rock tunnel blasting effect analysis evaluation model with fuzzy AHP for evaluating the blasting effect.The blasting effect,based on the experiments,was evaluated,and the results were consistent with the experimental results;Measures to improve the rock tunnel blasting effect of Dading Mountain mine were proposed on the results of the evaluation.