北京地铁运营隧道病害状态分析

基于北京地铁隧道病害检测结果，分析结构形式、配筋和运营时间对隧道病害状态的影响。研究结果表明,管片接缝变形是盾构隧道病害的根源，并由此引发了盾构断面的椭圆化变形、管片的压溃与错台以及盾构隧道的渗漏水。衬砌开裂是矿山法隧道的主要病害，裂缝宽度与深度受运营时间影响大且具有离散性强、随机性大的特点，配筋对隧道结构安全有积极影响。渗漏水受降水的影响较大，多出现于隧道衬砌结构的缝隙，如盾构隧道的接缝、螺栓孔或矿山法隧道的变形缝、施工缝和衬砌裂缝等。衬砌空洞多位于拱顶，形状接近于长条形、正方形和椭圆形，且多伴随着邻近衬砌的开裂。混凝土碳化深度与运营时间成正比，碳化深度和速率在隧道道床位置最大、边墙次之、拱顶最小。裂缝是整体式道床的常见病害，道床在剥离的同时还伴随沿其纵向的扭转。

Analysis on defects of operational metro tunnels in Beijing

Based on the inspection results of some metro tunnels in Beijing, the influences of structural form, steel bar and service time on the defects of metro tunnels were investigated. The research results indicate that the defects of shield tunnel such as ovalization of cross section, lining cracks, dislocation of duct pieces and water leakage are mainly attributed to the deformation of segment joints. Lining crack was the main defect form in mining tunnel, and the width and depth of cracks with the discrete and random characteristics are influenced greatly by the service time of tunnel. Steel bar in concrete lining has a positive effect on the tunnel safety. Water leakages in metro tunnel are influenced greatly by rainfall and they usually occur at the segment joints and bolt holes of shield tunnel or the construction joints, deformation joints and lining cracks of mining tunnel. Most of lining holes with the shape approximate to strip, square or oval are often located at the arch crown accompanying with lining cracking nearby. Carbonation depth of lining concrete is proportional to the service time. The carbonation depth and rate appear to be the most at ballast bed, the less at sidewall and the least at arch crown. Crack is the common defect at ballast bed, and the separation between ballast bed and tunnel is accompanied by the longitudinal torsion.