本文针对山区横穿坡体的浅埋油气管道的抗震防护问题,提出了一种新型的预制框架锚固式管道防护结构。在根据拟静力法和传递系数法确定设计地震滑坡推力与锚杆的设计锚拉力基础上,以次梁与下主梁结点处为界,将预制框架锚固结构拆分为上部结构与下主梁结构两部分。其中,上部结构可视作底端固定的超静定平面刚架结构,下主梁可视作受集中力与力偶作用的Winkler弹性地基梁,其间考虑了上部结构-下主梁-地基之间的变形协调关系,推导了相关计算公式,采用迭代方法实现了预制框架结构内力的计算求解。结果表明:框架结构的下主梁的弯矩与剪力的理论计算与数值模拟结果偏差均在10%以内,上部结构内力的理论计算与数值模拟结果差异亦较小;水平地震系数对下主梁与次梁内力影响显著;框架结构内力与土体重度和黏聚力、内摩擦角分别呈线性正相关性及非线性负相关性;下主梁的内力最大值与主梁抗弯刚度之间呈非线性正相关性,次梁内力最大值则与其呈非线性负相关性;框架结构的关键受力构件为下主梁与次梁,可据此对上主梁进行经济性优化设计。

Aiming at the aseismic protection of shallow buried petroleum pipelines crossing slopes in mountainous areas, a new type of prefabricated frame with anchor bolts pipeline protection structure is proposed. On the basis of determining the design seismic landslide thrust and the corresponding anchor force of the bolts in light of the pseudo-static method and transfer coefficient method, the prefabricated frame with anchor bolts is divided into the upper and lower parts with the boundary of the connection between the secondary beams and the lower main beam. Further, the upper part can be regarded as a super-static planar rigid frame structure with two fixed bottom ends, and the lower part can be considered as a Winkler elastic beam on foundation subjected to concentrated force and moment at the two connections. In particular, the deformation compatibility among the upper and lower parts as well as the foundation is fully considered, and the relevant calculation formulas are derived. An iterative method is proposed to specifically calculate internal forces of the prefabricated frame with anchor bolts. An example shows that the deviation between the proposed and the numerical simulation results of the bending moment and shear force on the lower main beam is less than 10%, and the difference between the proposed and the numerical results of the internal forces of the upper structure is also small. The horizontal seismic coefficient has a significant influence on the internal forces of the lower main beam and secondary beams. The internal forces of the frame have a linear positive correlation with the soil weight and cohesion, but a nonlinear negative correlation with the soil internal friction angle. There is a nonlinear positive correlation between the maximum internal forces of the lower main beam and the flexible rigidity of the main beam, while the maximum of the secondary beams has a nonlinear negative correlation with it. The key mechanical components of the frame are the lower main beam and the secondary beams, and the economic optimization design of the upper main beam can be accordingly carried out.