Research On The Calculation Model Of The Cut And Cavity Under The Columnar Charge

Blasting is commonly used in wells,tunnels and other engineering areas.In the project,due to the current lack of theoretical research on the cylindrical drug traps,many construction designs solve the problem of column loading charges by using the spherical drug pack groove theory,and that leading to large deviations in design results.Although the mechanical analysis system of rock crushing is complete,it is difficult to establish a blasting cavity theory from the mechanical point of view for high detonation velocity and large fracture engineering.Therefore,from the perspective of energy-breaking rock,this paper analyzes the energy-breaking rock boundary during the formation of blasting funnel,with the energy corresponding to the thickness of the rock mass being blasted.Based on the analysis of energy-breaking rock,a calculation model for trench formation is established.The feasibility and rationality of the model are verified by field experiments.The experimental results show that the established model is feasible and reasonable.The calculation model of the completed cavity is divided into three parts:the calculation model of the spherical charge blasting hopper,the calculation model of the single hole cylindrical charge blasting hopper,and the calculation model of the double hole cylindrical charge blasting hopper.The field test was carried out in two steps:a spherical cartridge and a single-hole cylindrical cartridge blasting funnel experiment,and a double-hole cylindrical cartridge blasting funnel experiment.When establishing the calculation model of the spherical charge blasting hopper,the differences and internal relations between the two classical ball charge blasting hopper theory are analyzed.In combination with the theory of explosive rock breaking,the mechanism of explosive rock breaking in infinite media and semi-infinite media is analyzed.The effect of explosive energy on the rock mass to be blasted is replaced by the depth of drug embedding.And the concept of energy partition of the funnel system and the subdomain is introduced.The slope of the funnel is used as the rock breaking limit of the energy breaking rock,finally,the calculation formula for the boundary of the blasting funnel is established as:R =,In the case of boundary determination,the calculation model of the volume of the explosion cavity is established by the geometric simplified parameters of the funnel as V=[（a₁,w²+b₁w+c₁）²-w²]w·π/3;Introducing the funnel slope coefficient as a measure of the size of the rock clamp,and the formula is:k=（?），This coefficient represents the case where the rock mass consumes explosive energy in a non-fragmented form.When the single-hole cylindrical blasting crater calculation model was established,the energy of the cylindrical drug pack could not be replaced by a single parameter,ie,the depth of the drug,as the spherical drug package could not be replaced.The energy relations of the rock mass are represented by more alternative parameter relationships;Based on the analysis of the initial energy distribution relationship of the detonation wave,the initial parameters of the impact of the blast energy on the rock mass are determined by taking the aperture ratio,the length of the drug column,and the length of the packing.Introducing the bottom radius function（F_T =√（L_Y+L_T）/L_Y.（D³/L_T³））,based on this,a formula for calculating the bottom radius of the blasting funnel is established:r_d =（aF_T² +bF_T+c）·D.Taking the relationship between the coefficient of production of spherical drug packs and the method of stacking cylindrical drug packs with spherical cartridges,a rock breaking model of the energy-breaking rock subdomain is introduced to combine the intrinsic rock-breaking mechanism of energy-breaking rock with the formation of the blasting funnel.A model for calculating the visible depth of a cylindrical blasting funnel based on energy-breaking rock is as W_k=L₁+r₁+X_b;According to the subdomain calculation model of energy-breaking rock and the simplified geometry model of blasting hopper,a cylindrical blasting bubble volume model was established.Finally,the bottom radius calculation model of the blasting funnel,the visible depth calculation model of the funnel,and the funnel volume calculation model are used as the cavity calculation model of the cylindrical charge blasting funnel.When establishing a double-hole cylindrical drug cartridge cavity calculation model,accept single-hole cylindrical drug cartridge cavity calculation model,still using the size of the funnel bottom and the depth of the funnel as the energy breaking rock boundary.By calculation simplification,the calculation model of the bottom radius of the blasting funnel,the visible depth calculation model of the funnel,and the funnel volume calculation model were established.Based on these calculation models,a two-hole explosion cavity calculation model was constructed.The verification experiments for the three explosion-cavitation calculation models were carried out in An-Hua Explosives Factory.Blasting funnel experiments were conducted by pre-cast concrete models,and the relevant parameters of the funnels were collected on site.Five groups of experiments were carried out to fix the material parameters and blasthole depth in the column blasting crater experiment,and the length of the column was changed.Five groups of experiments were performed to fix the material parameters and the length of the charge.The final experiment showed that the explosion was completed.The cavity calculation model is feasible.In the double-hole cylindrical blasting crater experiment,five sets of experiments were performed to fix the material parameters,the depth of the blasthole,and the length of the blasthole,and the distance between the blastholes was changed.The experimental results showed that the calculation model of the double-hole columnar drug trap cavity was feasible.