由于不利的地质条件和盾构施工期间的载荷,在段中不断观察到裂缝。但是,从长远来看,裂纹扩展可能会对分段结构的应力变形产生负面影响。揭示裂纹扩展过程中能量释放的特征可以有效地反映损伤演化过程。在对地铁隧道工程分段裂缝进行调查的基础上,通过相似的模型试验对分段的声发射数据进行了深入分析,并探讨了不同长度,数量和位置的裂缝对分段损伤演化的影响。盾构隧道。结果表明,与没有预备裂纹的扇形环相比,裂纹降低了结构的整体刚度,弹性支承范围略有增加,而塑性支承范围明显减小。随着准备裂缝的长度和数目的增加,AE事件的阶梯事件数量减少,阶梯高度增加,并且段的AE事件数目在不稳定性的临界点处连续增加。节段的损伤较早出现,并且损伤的发展过程相对较缓和,如果在弓形腰部有裂纹。相比之下,如果在拱顶和拱底处出现裂缝,则节段的损坏会更加严重。研究结果为盾构隧道的设计优化,病害分析和评价提供了理论依据。在不稳定性的临界点上,AE事件的梯形数量减少,梯形的高度增加,而段的AE事件数量连续增加。节段的损伤较早出现,并且损伤的发展过程相对较缓和,如果在弓形腰部有裂纹。相反,如果在拱顶和拱底出现裂缝,则各段的损坏会更加严重。研究结果为盾构隧道的设计优化,病害分析和评价提供了理论依据。在不稳定性的临界点上,AE事件的梯形数量减少,梯形的高度增加,而段的AE事件数量连续增加。节段的损伤较早出现,并且损伤的发展过程相对较缓和,如果在弓形腰部有裂纹。相反,如果在拱顶和拱底出现裂缝,则各段的损坏会更加严重。研究结果为盾构隧道的设计优化,病害分析和评价提供了理论依据。相反,如果在拱顶和拱底出现裂缝,则各段的损坏会更加严重。研究结果为盾构隧道的设计优化,病害分析和评价提供了理论依据。相比之下,如果在拱顶和拱底处出现裂缝,则节段的损坏会更加严重。研究结果为盾构隧道的设计优化,病害分析和评价提供了理论依据。
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Experimental study on damage evolution characteristics of segment structure of shield tunnel with cracks based on acoustic emission information
Cracks are constantly observed in segments due to adverse geological conditions and loads during shield construction. However, crack propagation can have a negative impact on the stress deformation of the segment structures in the long run. Revealing the characteristics of energy release during crack propagation can effectively reflect the damage evolution process. Based on an investigation of segment cracks in a subway tunnel project, this paper conducts an in-depth analysis of AE data of segments through similar model tests, and explores the influence of cracks of different lengths, quantities and positions on the damage evolution of segments of shield tunnels. The results show that cracks reduce the overall stiffness of the structure when compared with that of a segment ring with no prepared cracks, and the elastic bearing range increases slightly, while the plastic bearing range decreases obviously. With the increase of the length and number of prepared cracks, the number of ladders of AE events decreases and the height of ladders increases, and the number of AE events of segments increases continuously at the critical point of instability. The damage of segments appears earlier, and the development process of the damage and is relatively gentle if cracks are located at the arch waist. By contrast, the damage of segments is more serious if cracks are located at the arch roof and arch bottom. The results provide theoretical basis for design optimization, disease analysis and evaluation of shield tunnel.