Study On The Jacking And Motivating Technology Of Simple Supported Girder Bridge In The Mining Area

In this paper, a multi-span girders railway bridge was studied which would submerge about 3.5m influenced by coal mining on Huainan coal mining area. During the process of jacking and motivating bridge superstructure, construction organization arrangement is difficult, and the girder force situation is complex. The girder displacement and stress monitoring position is not clear, the jacking error allowable value is indeterminate, train dynamic load handling and other issues. Bridge substructure affected by mining subsidence, corrupted and position is not clear, whether the original foundation can be used and other issues.Jacking and motivating construction scheme was proposed, and the corresponding construction process was proposed too. Jacking and motivating equipment was also designed. Three kinds of finite element models of different girders about this railway bridge were established by finite element software ANSYS. The formula of relative displacement deformation of the bridge superstructure was proposed. The mechanical response situation of three different kinds of girders were detailedly analyzed by numerical simulating method. The most vertical jacking condition and various main girder relative displacement allowable value were obtained. Depending on the mechanical response situation of different girders influenced by relative displacement deformation, the displacement and stress monitoring position was designed for all girders. According to the main stress cloud of all girders in different load cases, the reasonable parameters of girders during jacking and motivating construction were gived. According to each of the girder dynamic analysis, using the dynamic magnification factor calculated, The train dynamic load is treated rationally.In this paper, two different kinds of finite element models of the railway bridge substructure were established, and the internal force situation in the condition of mining surface deformation was analyzed. Caps and pile connection was the most dangerous position when pile foundation was influenced by mining surface deformation, and the restoration measure was proposed, too. Independent broaden foundation was less affected by mining surface deformation, and the soil below the foundation was more affected, so the restoration measure must be adopted to prevent damage. In adddition, the influence of the curvation of the surface deformation on the foundation of the two bridges are more than slant deformation. The surface impacted by negative curvature is greater than positive curvature.