Deformation and failure of overburden soil subjected to normal fault dislocation and its impact on tunnel. (December 2022)

• Record Type: Journal Article
• Authors: Wang, Tianqiang; Geng, Ping; Li, Peisong; Wang, Qi; Wang, Liangjie
• Is Part Of: Engineering failure analysis. Volume 142(2022)
• Publication Date: 2022-12
• Subjects: Model test -- Fault rupture -- Ground deformation profile -- Deformation and failure of tunnel -- Reasonable fortification length; FMLs Full measurement linings -- HMLs Half measurement linings -- EP Earth pressure -- PEP The peak earth pressure -- PCS peak compressive strain -- PTS peak tensile strain -- Wf the length of fault fracture zone -- St the span of tunnel; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2022.106747
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: A large-scaled model test with a fault fracture zone and a specific dip subjected to normal fault dislocation. Fault rupture propagation characteristics combined with surface deformation profiles under the dislocation. The deformation and failure modes of linings with fault rupture transversely and longitudinally, and mechanical behavior investigation. Reasonable fortification length of segmentally designed tunnel. Abstract: In this study, a large-scaled model test was conducted to explore the deformation and failure mechanism of tunnel with fault rupture. The strain evolution, ground fissure and displacement, earth pressure and tunnel deformation are collected in the test. Then, tunnel mechanical behavior under the fault dislocation is revealed based on the test result. The results show that a prismoid-like 3D shear zone appeared within fault fracture zone. The tunnel experiences an elongated 'S'-shaped deformation along longitudinal axis of tunnel and the displacement changes of sectional linings within the shear zone are more significant. In transversely, the linings exhibit an oval horse-shoe deformation pattern. Three types of failure mode defined as Type Ⅰ, Type Ⅱ and Type III, corresponding to slight damage, moderate damage and severe damage, are summarized transversely in this paper. Under normal fault dislocation, the tunnel within the shear zone experienced a combination failure of bending moment and shear force. But compression failure of linings far from the fault would occur with longitudinal cracks on tunnel subjected to normal fault. Taking fault width ( Wf ) and tunnel span ( St ) into consideration, a reasonable tunnel fortification length was proposed with maximum of 2.25 Wf and 3.5 St under a specific fault dip of 60°. In the model test, when the fault dislocation reaches 10 mm, a slight crack begins to appear on arch foot of lining and then dislocation of joint occurs. Thus, corresponding to a prototype tunnel, a safe vertical displacement to ensure no damage to tunnel should be 34.6 cm when a segmentally designed tunnel is subjected to normal fault dislocation.