Experimental Study On Crack Propagation Driven By Detonation Gas

In recent years, a large number of resources have been invested in infrastructure construction at home and abroad. In order to ensure the safety and accuracy of blasting engineering, in the explosion, deflagration process, especially in the attenuation of stress wave and detonation gas as the main driving factors of the area, the detonation gas fracturing effects can not be ignored.Therefore, it is of great theoretical and practical significance to study the influence of various factors on the crack propagation.In this paper, in the process of blasting deflagration to detonation gas, the detonation gas crack,the crack configuration and extend the transient peak pressure, pre crack, loading speed to carry out research on indoor model test system. The phenomena and problems in the process of the experiment are analyzed and calculated. Finally, the crack propagation of the explosive gas is analyzed synthetically.The results of this study include the following:(1) The design and manufacture of the explosive gas generating device are completed. Based on the model of the previous scholars, the shape and size of the model are adjusted. A small step in the new direction of the experimental research on the pyrolysis gas explosion has been made up,which makes up for the blank of the laboratory test.(2) 0.2MPa gradient slow loading, the quasi-static loading test results show that the pre crack on the test model of integrity effect is not obvious, probably because the parts fit and compacting polyester film embedded pre cracks, avoid pre cracks the phenomenon of stress concentration; the test specimen used quasi static pressure peak value in 1.4?1.6MPa between.The results of quasi-static finite element analysis show that the pre crack has a significant effect on the integrity of the model.(3) Under the influence of three factors, such as the peak pressure, the length of the accelerating pipe and the pre crack, the transient loading. The transient loading test results show that the larger the transient pressure peak is, the greater the damage degree of the specimen is. The pre crack has a significant effect on the failure degree of the specimen. The results of transient finite element analysis and transient loading test are in agreement with the experimental results.Found three phenomena in the transient test results: 1) the transient loading peak is less than the quasi-static loading peak; 2) test results in the fracture shape and direction of the common; 3)under certain conditions, there is a certain threshold, the crack propagation.(4) The transient peak loading test 0.4MPa, can make the specimen leakage failure, below the quasi-static loading failure pressure peak phenomenon, respectively from the jet mechanics,theory of transient flow and transient compression three angles theory to analysis and calculation, the results show that the transient process is relatively more in line with the conditions of calculation of transient flow theory or compression transient theory. Two other experimental phenomena in the transient loading test are explained, and some suggestions for improvement are put forward. Finally, according to test results, the calculation process of the two times of deflagration combined perforating technology of crack propagation in rock driving,and put forward relevant opinions.