甘肃科学学报

反力结构为顶管顶进提供反力，能保证顶管工程顺利进行，结合不同顶进工况分析反力结构对顶管顶进的力学响应，既能确保顶进安全顺利进行，又能提高工程经济性。基于某下穿运河大断面矩形顶管顶进工程，通过建立三维精细化数值模型，分析反力结构在4种工况下的结构力学响应。结果表明，顶管向下纠偏(工况二)时顶管反力结构两侧上部角点处的弯矩以及轴力显著，在工程设计时应当对相应位置进行加强处理；4种工况下，反力结构左侧和右侧上部角点处弯矩和轴力总是相对显著，该处应针对性加强设计；顶管向左右侧单侧纠偏时(工况四),反力结构尾端的结构上部和下部反力差异显著，结构左侧和右侧反力差异较小；其他工况下反力结构尾端反力分布均匀，反力结构应进行相应优化以应对工况四的不利受力条件。

The reaction structure provides the necessary resistance for pipe jacking to ensure the smooth progress of the project.However, the jacking process often faces challenges such as uneven ground conditions and changes in jacking conditions, which may require adjustments to the jacking force to modify the pipe's alignment.A conservative design approach, such as using a monolithic reaction wall, can ensure safety but often lacks economic efficiency.Therefore, analyzing the mechanical response of the reaction structure under various jacking conditions is crucial to ensuring both safety and cost-effectiveness.Based on a large cross-section rectangular pipe jacking project under a canal, this study establishes a detailed 3D numerical model to analyze the mechanical response of the reaction structure under four working conditions:(1) all hydraulic jacks are activated;(2) only the upper hydraulic jacks are activated;(3) only the hydraulic jacks on both sides are activated;(4) only the left hydraulic jacks are activated.The results reveal that when the pipe is adjusted downward(working condition 2),significant bending moments and axial forces occur at the upper corner points on both sides of the reaction structure, which should be reinforced in design.Under four working conditions, the bending moments and axial forces at the upper corner points on the left and right sides of the reaction structure are always significant, suggesting reinforcement in these areas.When adjusting the pipe laterally(working condition 4),there is a notable difference in the reaction force between the upper and lower parts of the structure at the rear end, with minimal difference between the left and right sides, while under other conditions, the reaction force distribution at the rear end is relatively uniform.The reaction structure should be optimized to handle the unfavorable conditions in condition 4.