地下钢筋混凝土拱形结构在顶爆条件下的抗爆试验

拱形结构作为地下工程的主要结构形式之一,目前大多研究都集中在数值仿真上,所得到的结构破坏特征及响应数据缺乏相应的试验验证,不能充分地指导地下工程的抗爆设计。为研究地下钢筋混凝土拱形结构在爆炸荷载作用下的破坏模式及抗爆性能,对其在顶爆条件下开展了5个不同爆炸距离和装药量的试验。结果表明:在同一爆距下,随着装药量的增加,拱形结构的破坏程度逐渐增加,破坏模式为由背爆面产生裂纹发展为混凝土层裂脱落、钢筋隆起变形,直至拱顶中心处混凝土塌落显著、钢筋严重弯曲变形。顶爆下拱形结构的破坏不仅与比例爆距相关,还受到爆距的影响,同一比例爆距下,爆距越大拱结构的破坏越显著。通过分析位移响应与装药量及爆距的关系,初步提出了以挠跨比为依据的破坏等级划分方法,为今后的结构破坏评估分析提供试验支撑。

Blast Resistance Experiment of Underground Reinforced Concrete Arch Structure under Top Explosion

As the arch structure is one of the common structural forms of underground engineering,the majority of current research focuses on the numerical simulation.The numerical results of structural damage characteristics and response lack corresponding experimental verification,which cannot sufficiently guide the blast resistance design of underground engineering.In order to study the failure mode and blasting resistant performance of underground arch structures with reinforced concrete under explosive load,5 independent experiments under top explosion had been carried out with different blasting distances and charges.Results show that the damage degree of the arch structure gradually increases with the increase of charge under the same blasting distance.The characteristics of failure mode developed from the concrete cracks at the back surface of blast to the concrete spalling and deformation of steel bars.At last,the concrete collapsed significantly at the center of the vault and the steel bars were severely bent and deformed.The damage of the arch structure under top explosion is not only related to the scaled distance,but also affected by the blasting distance.Under the same scaled distance,the damage degree of arch structure increases significantly with the increase of blasting distance.By analyzing the relationships between the displacement response and the charge mass,the displacement response and the blasting distance,a method is initially proposed for dividing the damage grade based on the deflection?span ratio,which provides experimental support for the structural failure evaluation and analysis in the future.