新型优化弱化复合锚固结构抗爆宏观效应试验研究

EXPERIMENTAL RESEARCH OF NEW OPTIMIZED WEAKENED COMPOSITE ANCHORAGE STRUCTURE ON ANTI-BLAST MACROEFFECTS

论述新型优化弱化与非优化弱化复合锚固结构抗爆效应试验的目的、条件和方法,指出二者的唯一差异仅是弱化孔段长度不同,前者是优化的,后者是据经验确定的。试验特点是爆炸加载起始荷载低,级差小,试验真实地演绎洞室从变形→破坏→震塌堵塞的全过程。试验结果表明,前者的临界破坏抗力是后者的2.1倍以上,极限破坏条件下,拱顶下凸大变形尺度和面层脱落面积,前者仅为后者的25%和33%。弱化孔群的作用机制就是在围岩介质中形成一个弱化区,使原有的二介质系统(支护结构和围岩)成为三介质系统(支护结构、弱化区和围岩),并在爆炸过程中由弱化区大量吸收爆炸能,同时使支护结构的危机得以转移。

The objectives,conditions and methods for anti-blast effect tests of the new optimized and nonoptimized weakened composite anchorage structures are described.The only difference between the two types of structures is the length of weakened hole section.The former is optimized,while the latter is empirically determined.The experiments are characterized by low initial loads and small load increments.The experiments truly represent the whole process of chamber from deformation through failure to collapse and blockage.Experimental results show that the critical failure resistance of the former is more than 2.1 times as much as that of the latter.Under the extreme failure conditions,the large deformation dimension（arch crown lowering） and the surface spalling area of the former are only 25% and 33% that of the latter,respectively.The mechanism of weakening hole group is to form a weakened zone in the surrounding rock to turn the original two-medium system （support structure and surrounding rock） into a three-medium system（support structure,weakened zone and surrounding rock）.The weakened zone will absorb a great deal of explosion energy during explosion,and transfer the crisis of the support structure at the same time.