不同因素影响下混凝土立柱爆破效果的模型试验研究

钢筋混凝土建（构）筑物爆破拆除过程中，混凝土立柱最终的破碎效果不仅与炸药单耗、孔网参数等有关，还与立柱的受力状态有关。为研究截面应力和单位面积炸药量对不同强度混凝土立柱破碎效果的影响，利用自主研制的力学试验系统进行了15组爆破试验，从碎块筛分和分形维数两方面分析爆破效果。结果表明:对于相同强度的试件，截面应力一定时，随着单位面积炸药量的增加，分形维数整体上不断递增；但单位面积炸药量超过0.18 kg/m²后，增势有所放缓，截面应力为2 MPa和4 MPa的立柱趋势变化最为明显。单位面积炸药量一定时，随着截面应力的增加，碎块分形维数不断增大，当单位面积炸药量小于0.15 kg/m²时，0~2 MPa之间的截面应力增加会对分形维数有一定的抑制作用；当单位面积炸药量大于0.15 kg/m²时，截面应力的增加对分形维数起到促进作用。可为拆除爆破中的参数设计及优化提供理论依据，达到了控制爆破危害、改善爆破效果的目的。

Model Test Study on Blasting Effect of Concrete Column under Different Influencing Factors

In the process of blasting demolition of reinforced concrete buildings (structures), the final crushing outcome of concrete columns is not only related to the factors such as unit consumption of explosive and mesh parameters, but also related to the stress state of columns. In order to study the crushing outcome of concrete columns with different strength under the influence of section stress and mass of explosive per unit area, 15 groups of blasting tests were carried out using the self-developed mechanical test system, and the blasting outcome was analyzed from fragment screening and fractal dimension. Results show that, for the specimens with the same strength, when section stress is constant, the fractal dimension increases with the increase of mass of explosive per unit area. However, when the mass of explosive per unit area exceeds 0.18 kg/m², the increasing trend slows down, and the trend of column with section stress of 2 MPa and 4 MPa is the most obvious. When the mass of explosive per unit area is constant, the fractal dimension of fragments increases with the increase of the section stress. When the mass of explosive per unit area is less than 0.15 kg/m², the increase of section stress between 0 and 2 MPa will show a certain inhibition effect on the fractal dimension. When the mass of explosive per unit area is greater than 0.15 kg/m², the increase of section stress promotes the fractal dimension.