【摘要】 连续梁桥部分桥跨爆破拆除时极易对邻近桥跨产生较大的损害，为同时保证桥梁倒塌破碎效果和相邻桥跨的安全，以安康市某连续梁桥病害部分桥跨拆除爆破工程为例，利用ANSYS/LS-DYNA软件分别对上部箱梁水压爆破和下部桥墩逐排倾斜倒塌、逐跨倾斜倒塌、从中间向两边倾斜倒塌进行了模拟分析，根据桥体破碎效果、桥梁倒塌姿态以及塌落振动速度确定了最佳爆破方案，依据模拟结果进行了爆破设计并对振动速度进行了安全校核。结果表明：上部箱梁水压爆破梁体较为破碎，且爆破飞石较少防止其对邻近桥跨产生较大的冲击；在爆破前变连续梁为简支梁，并在爆破时先起爆邻近桥跨主梁处药包，随后下部桥墩采用逐排倾斜的倒塌方案可以在保证桥梁倒塌破碎效果的同时减小振动速度确保邻近桥跨的安全；现场实际桥梁爆破效果较好，且倒塌过程与数值模拟结果大体一致，邻近桥墩处无明显损伤，数值模拟监测点处最大振速峰值为3.58 cm/s,现场监测为3.96 cm/s,数值模拟结果较为准确。更多还原

【Abstract】 The blasting demolition of partial spans in continuous beam bridges frequently entails substantial risks of damage to the adjoining spans.To ensure the effective collapse and fragmentation of the bridge while safeguarding the integrity of adjacent spans, a case study was undertaken focusing on the blasting demolition of a damaged section of a continuous beam bridge in Ankang City.Using ANSYS/LS-DYNA software, numerical simulations were conducted to investigate the impact of water pressure blasting on the upper box girder and evaluate various collapse scenarios for the lower piers.These scenarios included row-by-row inclined collapse, span-by-span collapse, and center-to-both-sides collapse patterns.The optimal blasting scheme was identified by comprehensively evaluating three key parameters: structural fragmentation efficiency, collapse configuration, and induced vibration velocity during demolition.Based on these simulation findings, an optimized blasting design was developed, with subsequent safety verification conducted on the vibration velocities to ensure structural integrity and operational safety.The results demonstrate that implementing water pressure blasting in the upper box girder successfully achieved substantial structural fragmentation while effectively controlling debris dispersion and minimizing potential impacts on neighboring spans.Through a strategic approach involving the conversion of the continuous beam into a supported configuration prior to demolition, coupled with a sequential detonation protocol initiating at the main beams of adjacent spans followed by row-by-row inclined collapse of the lower piers, the proposed scheme successfully achieved controlled bridge demolition.This methodology ensured optimal structural fragmentation while reducing vibration velocities within safe thresholds, effectively protecting adjacent spans.The field implementation results aligned well with the numerical simulations, as evidenced by the controlled collapse process and satisfactory fragmentation patterns observed during the on-site blasting operation.No significant damage was observed in the proximate piers.The peak maximum vibration velocity recorded at the monitoring points in the numerical simulation was 3.58 cm/s, closely aligning with the field-measured value of 3.96 cm/s, demonstrating the simulation results′ reliability.更多还原