The 4th Engineering Co., LTD of China Railway 18th Bureau Group
Study on Collapse Mechanism of Soil-Rock Composite Strata with Geological Defects Induced by Construction of Metro Tunnels
Based on the background of a highway connecting line project crossing a large diameter water supply pipeline, the natural frequency and vibration mode characteristics of reinforced concrete and steel, circular and square cross-section pipelines were studied using theoretical analysis and numerical simulation method. The variation laws of vibration velocity and stress of underground pipelines with distance were explored, and the vibration velocity and stress response characteristics of the blasting side were compared with the back blasting side. Finally, the safety vibration velocity control standard of underground pipelines was obtained. The results show that: The first-order natural vibration frequencies obtained from theoretical analysis and numerical simulation were basically consistent. The natural vibration frequency of the steel pipeline was greater than that of the concrete pipeline, and the natural vibration frequency of the circular pipeline was greater than that of the square pipeline. The spring stiffness K has little effect on the natural vibration frequency of the pipeline, and its natural vibration frequency mainly depends on the material and shape. In terms of vibration mode, the vibration modes of circular pipeline and square pipeline are not the same, which mainly depends on the shape of the pipeline. With the increase of blasting distance, the overall trend of axial peak vibration velocity and peak stress of underground pipelines is gradually decreasing. The vibration velocity and stress of the pipeline are the largest at the explosion side, followed by the explosion side and the smallest on both sides. The pipeline is most prone to tensile failure at the explosion side and the back explosion side. According to the failure criterion of concrete pipeline unit, the safety vibration velocity control standard of pipeline is set to 3.5 cm / s, which can provide theoretical basis and practical guidance for subsequent similar blasting projects.
郑国和,王岗,宋祥刚,等. 地下输水管线自振频率及爆破振动特征研究[J]. 科学技术与工程, , ():复制