Calculation method of reasonable delay time of single-hole-interval millisecond vibration-absorbing blasting of electronic detonator

Abstract

The invention relates to a calculation method of reasonable delay time of single-hole-interval millisecond vibration-absorbing blasting of an electronic detonator. The method comprises the following steps: acquiring tunnel surrounding rock density and longitudinal wave propagation speed cP; measuring plane geometry parameters of each blast hole; calculating the diameter, the blast depth and the charge coefficient of each blast hole; calculating the time for stress wave arriving at the closest free face after a blasting cartridge in each blast hole blasts; calculating the time t2n for a crack,arriving at an excavating face, of each blast hole in the blast hole length direction; calculating the time t3m for a prism object throwing to reach the distance of 10cm from a new free face, whereinthe prism object is encircled by the blasting cartridge in each blast hole after blasting; calculating the total delay time of the electronic detonator in each blat hole; calculating blasting seismicperiod Tn of assisting holes and surrounding holes under different charge mass; setting the delay time of the electronic detonator in each blast hole based on the calculation result; and adjusting thedelay time of each blast hole based on the field blasting test and the monitoring result. With the adoption of the method, good ore crushing effect is ensured; the blasting vibration is greatly absorbed; the social benefit and the economic benefit are high.

Description

Technical field: [0001] The invention belongs to the technical field of tunnel blasting, and relates to a method for predicting reasonable time delay of blasting, in particular to a method for calculating reasonable time delay of electronic detonator single-hole interval differential vibration reduction blasting. Background technique: [0002] When using the drill and blast method to build tunnels in cities, many complex environment tunnels are often encountered, such as tunnels under dense urban buildings with a depth of 10-50m at short distances, underground municipal Pipeline tunnels, new tunnels with a net distance of less than 10m from existing tunnels, etc. Tunnel blasting vibration often endangers the safety of surrounding buildings (structures), municipal pipelines and subways. At present, non-electric millisecond detonators are widely used in engineering to control tunnel blasting vibration, but this technology has great limitations. The electronic delay function ...

AI Technical Summary

Problems solved by technology

When the single-hole delay is set too short, the rock breaking and throwing are not completed, and the air surface is not completely formed, which is equivalent to simultaneous detonation of two or more blast holes, which is not conducive to reducing blasting vibration; when the single-hole delay is set too long, the It is not conducive to the overlapping and crushing of rocks between adjacent blastholes, which has a greater impact on the blasting of cutting holes

When blasting a cut hole, since there is only one empty face on the face of the hole, the clamping effect of the surrounding rock is relatively large. The throwing of the broken rock of the blast hole also lacks the boosting force of the high-pressure gas generated by the blast hole next to the blast hole, causing the rock in the cut hole to be broken but not completely thrown out, making it difficult to form a new empty surface, resulting in the failure of the cut and affecting subsequent blasting

However, there is no time-delay calculation method for the electronic detonator to achieve single-hole interval differential vibration reduction blasting.

Images