【摘要】 针对黄土地区盾构隧道背后空洞会对管片的受力和结构变形造成不利影响而危害地铁的运营安全问题，本文结合某典型黄土盾构隧道背后空洞扫描和病害调查结果，并基于传统荷载-结构法，提出模拟空洞的方法，分析背后空洞对结构受力和变形的影响。研究表明：拱肩空洞与无空洞工况相比，结构上的弯矩和径向变形量增长6%,拱腰空洞与无空洞工况相比结构上的弯矩最大增长了56%,径向变形量最大增长46%,拱肩、拱腰空洞对于轴力的影响稳定在10%以内。当空洞位于拱腰时，伴随着空洞范围的不断扩大，结构上的弯矩最大增长69%,径向变形量最大增长64%,结构轴力的变化幅度在15%左右。拱腰空洞对结构受力、变形的影响远大于拱肩空洞。空洞位置、范围大小对结构轴力的影响程度较小。土体浸水软化后，增加了空洞对结构受力和变形的不利影响，弯矩最大增长90%以上，结构径向变形量最大增长了65%。更多还原

【Abstract】 The presence of cavities behind the segments of a shield tunnel affects the stress distribution and structural deformation of the segments, thereby jeopardizing the safety of metro operations. In loess regions, when the surrounding loess becomes saturated and undergoes softening, it further exacerbates the adverse effects of the cavities on the structure.To this end, this work combines the results of scanning and damage investigation of a typical Loess shield tunnel with cavities behind the tunnel lining. Based on the traditional load-structure method, a simulation approach for the cavity and analyzes its impact on structural stress and deformation was proposed.The research results are as follow. To the no-cavity condition, the bending moment and radial deformation for the arch shoulder cavity increase by approximately 6%. For the arch waist cavity, the maximum increase in bending moment is 56%, and the radial deformation increases by 46%. The impact of cavities in both the arch shoulder and arch waist on axial force remains within 10%. When the cavity is located in the arch waist and its size continuously expands, the maximum increase in bending moment is 69%, and the radial deformation increases by 64%. The change in axial force remains around 15%. Comparatively, the impact of the arch waist cavity on structural stress and deformation is greater than that of the arch shoulder cavity. The location and size of the cavity have a relatively minor effect on axial force. After the surrounding loess becomes saturated and undergoes softening, the adverse effects of the cavities on structural stress and deformation increase significantly. The maximum increase in bending moment exceeds 90%, and the maximum increase in radial deformation reaches 65%.更多还原