地应力对岩体爆破块度分布特征的影响研究  

Influences of in-situ stress on distribution characteristics of rock blasting fragmentation

作　　者：曹泽铭 杨建华 叶志伟 冷振东 姚池[1] 张小波[1] CAO Zeming;YANG Jianhua;YE Zhiwei;LENG Zhendong;YAO Chi;ZHANG Xiaobo(School of Infrastructure Engineering,Nanchang University,Nanchang 330031,China;Gezhouba Group Explosive Co.,Ltd.,Chongqing 401121,China)

机构地区：[1]南昌大学工程建设学院,江西南昌330031 [2]中国葛洲坝集团易普力股份有限公司,重庆401121

出　　处：《岩土工程学报》2024年第10期2202-2211,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52179102,51969015);江西省自然科学基金项目(20224BAB214079,20232BAB204090)。

摘　　要：深地工程高地应力岩体爆破开挖时常出现岩体破碎难、大块率高的问题。为深入理解这一问题,采用动力有限元方法模拟不同地应力条件下的岩体爆破开裂过程,引入爆生裂纹分形维数和岩体爆破块度图像识别方法,研究地应力对岩体爆破爆生裂纹分布和块度分布特征的影响,并通过不同埋深和地应力水平下的岩体爆破工程实例进行验证。研究结果表明:地应力对炮孔远区爆生裂纹扩展的抑制作用以及非静水地应力对爆生裂纹扩展的导向作用,导致了岩体爆破大块的产生;随着地应力水平的提高,岩体爆破平均块度尺寸、最大块度尺寸、块度不均匀系数和大块率均显著增加;炮孔近区的爆生裂纹扩展几乎不受地应力的影响,从而使得地应力对岩体爆破小块度的尺寸影响不大;垂直于炮孔轴向的两个主地应力差别较大时,不利于爆破破岩,侧压力系数约为0.75时,岩体破碎效果较好。During blasting excavation of deep rock masses under high in-situ stress,the rock masses are often difficult to be fully broken,frequently resulting in large fragments.To understand this problem more deeply,the blast-induced rock cracks under various in-situ stress conditions are simulated by using the dynamic finite element method.The fractal dimension theory and the image recognition method are introduced to investigates the influence of in-situ stress on the distribution characteristics of rock blasting fragmentation.The project cases blasted at different depths and in-situ stress levels are also employed to study this problem.The results show that the generation of large fragments during blasting in deep rock masses owes to the inhibiting effect of in-situ stress on the growth of blast-induced cracks in the far field of blastholes,and the orienting effects of the non-hydrostatic in-situ stress on the propagation of blast-induced cracks.As the in-situ stress level increases,average size,the maximum size,nonuniform coefficient and large block rate of rock fragmentation increase significantly.The size of the smaller fragments is little affected by the in-situ stress as these fragments are generated in the vicinity of blastholes and the propagation of blasting cracks in this zone is almost unaffected by the in-situ stress.When the maximum and minimum principal in-situ stresses perpendicular to the blasthole axis differ greatly,it is adverse to rock fragmentation by blasting.In comparison,a better rock fragmentation is achieved when the lateral coefficient of the principal in-situ stresses is about 0.75.

关 键 词：深地工程 爆破 地应力 爆生裂纹 爆破块度 

分 类 号：TU432[建筑科学—岩土工程]