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从西安地铁隧道工程背景和西安地裂缝地质环境出发,根据相似理论设计马蹄形隧道衬砌结构40°斜穿地裂缝的物理模型试验。结构模型混凝土应变、纵向和环向钢筋应变、结构外围土压力、结构内部收敛位移、模型顶表面土体变形以及宏观变形破坏现象表明:整体式马蹄形隧道衬砌结构40°斜穿地裂缝时其破坏模式为扭转、弯曲、剪切变形破坏,变形破坏不对称;衬砌混凝土环向裂缝主要分布在上盘区0.83D(D=1.8 m)、下盘区1.11D;纵向裂缝主要分布在上盘区1.11D、下盘区(1.94～2.22)D;下盘结构变形破坏范围和程度要高于上盘。马蹄形隧道结构在40°斜穿地裂缝时,宜采用分段方式来应对扭转、弯曲、剪切变形,应加强结构抗扭设计,扩大断面或提高混凝土强度等级来应对剪切变形。
Based on the background of Xi’an subway tunnel project and the geo-environment of Xi’an fissure, the physical model test of 40 ° diagonal through ground fissures of horseshoe tunnel lining structure was designed based on the similarity theory. The strain of concrete, the strain of the steel in the longitudinal and circumferential directions, the pressure of the soil in the periphery of the structure, the internal convergence and displacement of the structure, the deformation of the soil on the top surface of the model and the macroscopic deformation and failure phenomenon show that the monolithic horseshoe tunnel lining structure is damaged by 40 ° The modes are torsional, bending and shear deformation, and the deformation and destruction are asymmetric. The circumferential cracks in lining concrete are mainly distributed in the upper plate area 0.83D (D = 1.8 m) and the lower plate area 1.11D. The longitudinal cracks are mainly distributed in the upper plate area 1.11D, under the panel (1.94 ~ 2.22) D; under the disk structure deformation damage range and extent higher than the upper plate. When the horseshoe tunnel structure penetrates the ground fissure at 40 °, it is appropriate to adopt the sectional mode to deal with the twisting, bending and shear deformation. The torsional design of the structure should be strengthened, the section should be enlarged or the concrete strength level should be enlarged to deal with the shear deformation.