Experimental study on characteristics of rock fracturing by high-pressure foam
In view of the shortcomings of the drilling and blasting method and the mechanical method in rock breaking engineering,based on the high viscosity and compressibility of foam,the rock-fracturing technology by high-pressure foam is proposed.Firstly,the rock fracturing devices by high-pressure foam are designed,the process of high-pressure foam instantaneous release to boreholes is theoretically analyzed,and then the testing devices for rock fracturing force by high-pressure foam are built and the relevant experiments are carried out.By using the developed experimental system of rock fracturing by high-pressure foam,the foam-fracturing characteristics with different air volume fractions are investigated,and the mechanism of high-pressure foam fracturing is revealed.The results show that when it is released,the high-pressure foam can produce a higher fracturing force than the initial foam pressure,but the fracturing force increases and then decreases with the increase of the air volume fraction of foam.The high-pressure foam fracturing goes through four stages of crack initiation,crack expansion,crack separation and end of cracking.The rock-breaking weight increases and then decreases with the increase of air volume fraction.When the air volume fraction is 60%,the rock-breaking form is blasting crater,which is mainly caused by the tensile stress generated by the compressive stress waves reflected on the rock upper surface.When the air volume fraction is 70%～90%,the rock-breaking form is stripped large stones,which is mainly caused by the effects of the stress concentration at the bottom of boreholes.
high-pressure foamrock fracturingcrack propagationfracturing force
万方数据
维普
