隧道衬砌裂缝对结构受力的影响规律研究

Research on the influence law of tunnel lining cracks on structural forces

以深圳某区间隧道为研究背景,采用结构-荷载模型,研究了裂缝位置、裂缝深度及裂缝宽度对衬砌结构受力的影响。研究结果表明:隧道衬砌裂缝的产生使结构出现了应力重新分布的现象。当裂缝发生在拱顶位置时,隧道衬砌弯矩、剪力分别呈对称和反对称分布;当裂缝发生在拱肩、中墙或墙脚位置时,随着裂缝深度的增加,衬砌结构弯矩由近似对称向不对称变化,最大弯矩值由仰拱向拱顶部位扩散,左墙脚处出现最大负剪力值,右拱脚或左拱肩处出现最大正剪力值。随着裂缝宽度的增加,衬砌典型位置处弯矩和剪力均减小,当裂缝宽度由5 mm扩大到10 mm时,对单元受力结构影响最明显。随着裂缝深度和宽度的变化,隧道衬砌最危险截面的位置也发生了变化,需要对隧道不同部位加强监测,判断裂缝的发展状况,以保证人员、设备的安全,可为实际工程安全施工和健康运营提供指导。

Taking an interval tunnel in Shenzhen as the research background,the influence of crack location,crack depth and crack width on the force of lining structure is studied by using the structure-load model.The calculation shows that the appearance of cracks causes the stress redistribution of the structure.When the crack occurs at the vault,the bending moment and shear force of tunnel lining are symmetrical and antisymmetric respectively,When the cracks occur at the spandrel,sidewall orarch foot,the bending moment of lining structure changes from approximate symmetry to asymmetry with the increase of crack depth.The maximum bending moment diffuses from the invert to the vault,and the maximum negative shear force appears at the left arch foot,and the maximum positive shear force appears at the right arch foot or left arch shoulder.With the increase of crack width,the bending moment and shear force at the typical position of lining decrease,when the crack width expands from 5 mm to 10 mm,the effect on the stress structure is most obvious.With the change of crack depth and width,the position of the most dangerous section of tunnel lining also changes.It is necessary to strengthen the monitoring of different parts of the tunnel,analyze and judge the development of cracks to ensure the safety of personnel and equipment.This study can provide guarantee and guidance for the safe construction and healthy operation of practical projects.