通过对兰新二线全预应力混凝土槽型梁在非对称竖向荷载作用下的足尺模型试验,研究结构在逐级增大荷载作用下的变形、应力变化和裂缝开展及分布等规律,验证了该槽型梁的设计理论和施工质量,为槽型梁受力理论的发展积累了经验.研究结果表明:在竖向非对称荷载作用下,槽型梁具有明显的空间受力特征:腹板不仅发生竖向的弯曲变形,还会发生横向向槽口内的变形,底板则受纵向弯矩和横向弯矩共同作用,而腹板和底板结合处往往受弯扭组合变形共同作用,应力状态复杂;荷载等级越大,扭转变形对结构的影响越大,弯扭组合效应越明显;在一定的荷载范围内,腹板和底板应力的增长随荷载等级的增加近似符合线性增大的规律,在荷载增大的过程中,底板应力变化明显,中性轴会发生明显移动,而腹板中性轴几乎不发生移动;结构的设计理论和施工质量均满足列车营运的要求,并具有充足的安全系数.%Through the full scale model test of prestressed concrete channel beam of second double line of Lanzhou-Urumqi railway under vertical asymmetrical load, the deformation, the stress and the formation and distribution law of cracks were investigated. The design theory and the quality of construction were verified, which accumulated experience for the development of channel beams. Results show that channel beams exhibit obvious space stress characteristics when they are under asymmetrical load. The web occurs not only bending deformation in the vertical direction, but also deformation in transverse towards channel. The floor is subjected to the combined action of vertical bending moment and lateral bending moment, and the combined division of web and floor is often affected by the interaction of bending and torsion deformation. Therefore, the stress state of the structure is complex. With the greater load, the more obvious effect of torsion deformation on the structure and the more obvious effect of bending and torsion. In a certain range of step-increasing load, the stress of web and floor increases linearly and the neutral axis of the bottom plate changes significantly, while the neutral axis of the main beam does not move significantly with the change of load. The structural design theory and construction quality meet the requirements of the train operation, and it has sufficient safety factor.
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