振动下沉桩施工对受损桥梁影响范围计算

应用计算机仿真分析法、振动理论求解法与小孔扩张理论, 结合九江大桥事故现场情况, 研究了振动桩施工对周围地基土的影响范围。采用计算机仿真分析法, 模拟振动荷载作用下地基土的横向位移, 根据位移的递减规律得出其影响范围为20 m; 根据振动理论, 考虑振动波在地基土中的衰减因素, 得出其影响范围为15 m; 利用小孔扩张理论, 研究了孔径与地基土弹塑性区范围的关系, 得出其弹性区边界, 即影响范围为23 m。3种计算方法所得安全距离范围在15~23 m, 实际施工中须综合考虑打桩速率、打桩顺序及打桩工艺等因素, 综合考虑理论计算结果、工程现场实际情况和已有的实测结果, 工程处理安全范围选用18 m。事故处理平台振动下沉桩基础施工中的振动波没有引起周边环境的进一步坍塌, 因此, 安全距离范围合理。

Influence range calculation of damaged bridge during vibropile construction

The influence range of damaged bridge during vibropile construction on surrounding soil was studied in the actual accident scene of Jiujiang Bridge by using vibration theory, cavity expansion theory and simulation analysis.The lateral displacement of foundation soil under vibration load was simulated, and the influence range was 20 m according to the diminish law of displacement.According to vibration theory, the attenuation of vibration wave in foundation soil was considered, and the influence range was 15 m.Using cavity expansion theory, the relationship between the aperture and the plastic zone for the soil was analyzed, and the influence range was 23 m.The influence ranges were between 15 m and 23 m.The factors such as piling rate, piling order and piling process were considered under the construction, according to the theoretical computation results, the processing scheme of actual project and measure result, the intended safe distance is 18 m.Applied result shows that the vibration wave caused by the construction of accident treatment platform's vibropile foundation, does not cause further collapse in surrounding environment, so the influence range of theoretical analysis is scientific and reasonable.