论文部分内容阅读
隧道近接上覆水平采空区地层施工易扩大上覆围岩松动范围,增大松动荷载,为探明隧道衬砌结构受荷特性,采用室内相似模型试验量测了上覆水平煤层采空区地层隧道二次衬砌结构内力(轴力、弯矩),分析了不同边界压力作用下位移、轴力和弯矩的变化情况和特定压力下间距对二次衬砌受力的影响。结果表明:上覆采空区对洞周位移和二衬内力造成了一定影响,采空区底板与隧道间距越小,位移越大,当竖向压力为1000 k Pa时,与无采空区工况相比,0.5D工况最大位移增加93.73%,1.0D工况增加27.90%;弯矩和轴力的增加越明显,当竖向压力为500 k Pa时,与无采空区工况相比,间距0.5D工况最大弯矩增加139.68%,间距1.0D工况最大弯矩增加34.39%,采空区的存在导致轴力分布形态变化较大,间距0.5D工况平均轴力增加78.39%,间距1.0D工况平均轴力增加37.81%;最大偏心距出现在仰拱部位,承载能力相对较低,是隧道主体结构的薄弱环节;二次衬砌仰拱位置最先开裂,煤层采空区对裂缝展开顺序有一定影响。
In order to find out the load characteristics of the tunnel lining structure, the similarities between the tunnel and the stratum of goaf overlying overlying coal seam are measured by measuring the loose area of overlying rock and increasing the loose load. The internal forces (axial force and bending moment) of the secondary lining of the tunnel are analyzed. The displacement, axial force and bending moment under different boundary pressures and the influence of spacing under specific pressure on the secondary lining are analyzed. The results show that the overlying goaf has a certain influence on the displacement of the perimeter of the tunnel and the internal force of the liner. The smaller the distance between the floor and the tunnel of the goaf, the larger the displacement. When the vertical pressure is 1000 kPa, The maximum displacement of 0.5D working condition increased by 93.73% and the working condition of 1.0D increased by 27.90% compared with the working condition. The bending moment and axial force increased more obviously. When the vertical pressure was 500 kPa, Compared with the 0.5D condition, the maximum bending moment increased by 139.68% and the maximum bending moment increased by 34.39% at the 1.0D condition. The mined-out area resulted in a large change of the axial force distribution and the increase of the average axial force at the 0.5D condition 78.39%, the average axial force of 1.0D condition increases by 37.81%; the maximum eccentricity occurs in the inverted arch area and the bearing capacity is relatively low, which is the weak link of the tunnel main structure; The empty zone has a certain influence on the order of crack initiation.