直螺栓连接预制综合管廊刚度计算方法

为研究直螺栓连接预制管廊的纵向受力性能,引用隧道纵向刚度计算的纵向等效连续化模型,对其进行改进,使其适用于直螺栓连接的预制管廊,从而得到考虑螺栓预应力影响的纵向等效拉压刚度和弹性弯曲刚度。求得了预制管廊在弹性极限弯矩作用下,截面最大拉应力、截面最大压应力、接头最大变形、接头螺栓最大拉应力和接头螺栓最大变形的表达式。运用所得表达式,结合工程实例参数,分析了管廊截面尺寸、管壁厚度、节段长度和螺栓个数对其受弯矩作用时中性轴的位置和纵向等效刚度的影响程度和趋势。结果表明,管廊抗弯刚度受截面宽高比影响较大；通过增加管壁厚度来提高管廊等效刚度的方法不经济；在满足设计要求条件下,适当增大预制节段的长度和增多连接螺栓数量可以有效提高管廊的纵向刚度,并能够很好的改善管廊截面受力状态,同时不失经济性,为直螺栓连接预制拼装管廊结构的设计合理性和工程适用性提供理论支持。

Calculation method of stiffness of prefabricated comprehensive pipe gallery connected by straight bolts

In order to study the longitudinal mechanical performance of the prefabricated pipe gallery connected by straight bolts, the longitudinal equivalent continuity model for the calculation of the longitudinal stiffness of the tunnel is cited and improved to make it suitable for the prefabricated pipe gallery connected by straight bolts, so as to obtain the longitudinal equivalent tension compression stiffness and elastic bending stiffness considering the influence of bolt prestress. The expressions of the maximum tensile stress of the section, the maximum compressive stress of the section, the maximum deformation of the joint, the maximum tensile stress of the joint bolt and the maximum deformation of the joint bolt of the prefabricated pipe gallery under the elastic limit moment are obtained. Using the obtained expression and combined with engineering example parameters, the influence degree and trend of pipe gallery section size, pipe wall thickness, section length and bolt number on the position of neutral axis and longitudinal equivalent stiffness under bending moment are analyzed. The results show that the bending stiffness of the pipe gallery is greatly affected by the aspect ratio of the section; The method of increasing the equivalent stiffness of pipe gallery by increasing the thickness of pipe wall is not economical; Under the condition of meeting the design requirements, appropriately increasing the length of precast segments and increasing the number of connecting bolts can effectively improve the longitudinal stiffness of the pipe gallery, and can well improve the stress state of the pipe gallery section without losing economy, so as to provide theoretical support for the design rationality and engineering applicability of straight bolt connected precast assembled pipe gallery structure.