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| EXPERIMENTAL STUDY OF CRACK PROPAGATION UNDER BLASTING LOAD IN NOTCHED BOREHOLES |
| YUE Zhongwen，GUO Yang，WANG Xu |
| (School of Mechanics and Civil Engineering，China University of Mining and Technology，Beijing 100083，China) |
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Abstract In order to study the interaction between the blast-induced cracks and an empty hole under blasting load in notched boreholes，the blast-induced crack initiation and propagation in PMMA material with a circular empty hole under blasting load was studied with the digital laser dynamic caustics experimental system. During a simple borehole blasting，the blast-induced crack from a notched borehole B had a straight path，directly met the empty hole in the propagating process，was mostly in the tension stress field and grew as mode I. In the simultaneous blasting with two notched boreholes，the interaction between the empty hole and the main blast-induced cracks affected the main blast-induced crack propagation，and the two main blast-induced cracks were respectively coalesced with two blast-induced wing cracks. The propagation speed and dynamic stress intensity factor were reduced with the interaction between the compressive stress waves of P waves in explosive stress waves and the propagating cracks.
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| [1] BAKER L M. A simplified method for measuring plane strain fracture toughness[J]. Engineering Fracture Mechanics，1977，9(2)：365–369.
[2] FOURNEY W L，DALLY J W，HOLLOWAY D C. Controlled blasting with ligamented charge holders[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1978，15(3)：121–129.
[3] DALLY J W，FOURNEY W L. Fracture control in construction blasting—energy resources and excavation technology[C]// Proceedings of the 18th U.S. Symposium on Rock Mechanics. Colorado：[s. n.]，1977：1–7.
[4] JEONG D，MOON S，AN D，et al. A study on tunnel excavation method using notch hole for vibration and over-break control in rock mass[C]// Proceedings of the European Federation of Explosives Engineers. Vienna：[s. n.]，2007：195–204.
[5] WILLIAMS M L. Stress singularities resulting from various boundary conditions in angular corners of plates in extension[J]. Journal of Applied Mechanics，1952，19(4)：526–528.
[6] 杨仁树，王雁冰，岳中文，等. 定向断裂双孔爆破裂纹扩展的动态行为[J]. 爆炸与冲击，2013，33(6)：631–637.(YANG Renshu，WANG Yanbing，YUE Zhongwen，et al. Dynamic behavior of crack propagation in directional fracture blasting with two hloes[J]. Explosion and Shock Waves，2013，33(6)：631–637.(in Chinese))
[7] 杨仁树，王雁冰，杨立云，等. 双孔切槽爆破裂纹扩展的动焦散实验[J]. 中国矿业大学学报，2012，41(6)：868–872.(YANG Renshu，WANG Yanbing，YANG Liyun，et al. Dynamic caustic experimental study of crack propagation two borehole cut blasting[J]. Journal of China University of Mining and Technology，2012，41(6)：868–872. (in Chinese))
[8] 杨仁树，宋俊生，杨永琦. 切槽孔爆破机理模型试验研究[J]. 煤炭学报，1995，20(2)：197–200.(YANG Renshu，SONG Junsheng，YANG Yongqi. Study on the mechanism of notched-holes blasting by model experiment[J]. Journal of China Coal Society，1995，20(2)：197–200.(in Chinese))
[9] 肖正学，郭学彬，张志呈，等. 切槽爆破在爆炸冲击波和爆轰气体作用下的力学效应[J]. 岩石力学与工程学报，1998，17(6)：650–654.(XIAO Zhengxue，GUO Xuebin，ZHANG Zhicheng，et al. The mechanical effect of notched blasting under the explosive shock wave and explosive gas[J]. Chinese Journal of Rock Mechanics and Engineering，1998，17(6)：650–654.(in Chinese))
[10] 杜云贵，张志呈，李通林. 切槽爆破中V形切槽产生的力学效应研究[J]. 爆炸与冲击，1991，11(1)：26–30.(DU Yungui，ZHANG Zhicheng，LI Tonglin. Studies on the mechanical effects produced by the V-shaped notch borehole blasting[J]. Explosion and Shock Waves，1991，11(1)：26–30.(in Chinese))
[11] 于慕松，杨永琦，杨仁树，等. 炮孔定向断裂爆破作用[J]. 爆炸与冲击，1997，17(2)：159–165.(YU Musong，YANG Yongqi，YANG Renshu，et al. Model experimental study on mechanism of borehole directed fracture blasting[J]. Explosion and Shock Waves，1997，17(2)：159–165.(in Chinese))
[12] 张志呈，王成端. 切槽爆破中切槽角的研究[J]. 爆炸与冲击，1990，10(3)：233–238.(ZHANG Zhicheng，WANG Chengduan. Study on notching angle in notching blast[J]. Explosion and Shock Waves，1990，10(3)：233–238.(in Chinese))
[13] 宗 琦. 岩石炮孔预切槽爆破断裂成缝机理研究[J]. 岩土工程学报，1998，20(1)：30–33.(ZONG Qi. Investigations into mechanism of crack formation for grooved hole-well blasting[J]. Chinese Journal of Geotechnical Engineering，1998，20(1)：30–33.(in Chinese))
[14] 郑周练，陈山林，叶晓明，等. 螺旋切槽孔松动爆破模型试验研究[J]. 岩石力学与工程学报，2004，23(3)：446–449.(ZHENG Zhoulian，CHEN Shanlin，YE Xiaoming，et al. Model testing study on prefabricated spiral v-notch blasting[J]. Chinese Journal of Rock Mechanics and Engineering，2004，23(3)：446–449.(in Chinese))
[15] TAKAHASHI K，ARAKAWA K. Dependence of crack acceleration on the dynamic stress intensity factor in polymers[J]. Experimental Mechanics，1987，27(2)：195–217.
[16] PAPADOPOULOS G A. Fracture mechanics-the experimental method of caustics and the det.-criterion of fracture[M]. Berlin，Heidelberg，New York：Springer-Verlag，1992：134–204. |
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2015, Vol. 34 
