A physical and numerical investigation of the failure mechanism of weak rocks surrounding tunnels

Li, Yingjie; Zhang, Dingli; Fang, Qian; Yu, Qingchun; Xia, Lu

doi:10.1016/j.compgeo.2014.05.017

Cited by 73 publications

(17 citation statements)

References 35 publications

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“…Using a numerical model, a strain-softening model was selected to simulate the intact rhyolite ( Figure 9). This method has been extensively used to describe the nonlinear mechanical properties of rock around a tunnel [25]. The equivalent physical properties of the simulated material referenced to the experimental results [20,23,26] are shown in Table 2.…”

Section: Simulation Of Uniaxial Compressionmentioning

confidence: 99%

Study on Hysteretic Fracture of Naturally Cracked Surrounding Rock

Zhong¹,

Deng²,

Fang³

et al. 2015

Mathematical Problems in Engineering

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To determine the hysteretic fracture mechanism of the hard and naturally cracked surrounding rock mass, uniaxial and biaxial compression tests were performed on rhyolite specimens. In the biaxial compression test, displacements and strains around the U-shaped opening were monitored throughout to study the fracture pattern and distribution of stress. To compare with the experimental results, the finite difference codeFLAC3Dwas used to simulate a perfectly intact rock model with the same geometric and mechanical conditions in a continuum model. Stress-strain curves under uniaxial compression and the surrounding rock stresses of numerical results were compared with laboratory test. On one hand, laboratory test and numerical results all showed that tensile fracture regions were found at the crown and floor of the opening while shear regions are found at the sidewall. On the other hand, due to microcracks in the laboratory specimen, the laboratory test showed lower ultimate compressive strength. However, its vertical displacement of initial fracture was larger than those of numerical model which did not consider about the microcracks. They revealed the hysteretic fracture behaviour of underground opening in hard and cracked rock.

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Section: Simulation Of Uniaxial Compressionmentioning

confidence: 99%

Study on Hysteretic Fracture of Naturally Cracked Surrounding Rock

Zhong¹,

Deng²,

Fang³

et al. 2015

Mathematical Problems in Engineering

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“…Sun et al [8] recognized that soil dilation may have an adverse influence on the observed deformation and failure mechanisms at low stress levels. Li et al [9] determined that shear wedge damage in the direction of the minimum principal stress can easily lead to collapse in tunnels. Little attention was given to the analysis of the role of a pipe-roof in reducing soil settlement and providing stability improvement.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Behavior of Rectangular Excavations Supported by a Pipe Roof

2019

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This paper presents an experimental investigation of the role of pipe-roofs in the improvement of the stability of rectangular excavations constructed using pipe-roof technology. This technology is suitable for the construction of underground passages in crowded areas subjected to high requirements concerning soil settlement and stability during excavation construction. The design of a rectangular pipe-roof excavation required an understanding of the interaction between the soil, the pipe-roof and the excavation. This interaction is complex and plays an important role in the features of the pipe roof excavation. This paper presents a series of 1g physical experimental tests conducted in dry sand soil with an advanced monitoring system, which allows tracking of the soil settlement, the pipe deformation and the soil pressure. Analysis of these tests shows the effective role of the pipe-roof in reducing both the soil settlement and the soil pressure on the excavation. It also shows the influence of pipes on the deformation mechanism of the soil and its evolution from low deformation to the instability phase.

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“…Huang et al [19] explored the effect of a weak interlayer on failure patterns in a rock mass around a tunnel, both physical model tests and numerical analysis were carried out to simulate tunnel excavation near an interlayer. Li et al [20] developed a new large-scale physical simulation method to investigate the deformation and failure modes of weak rocks surrounding a tunnel. Fu et al [21] proposed a statistical model for predicting the triaxial compressive strength of transversely isotropic rocks subjected to freeze-thaw cycling.…”

Section: Introductionmentioning

confidence: 99%

Instability Process of Crack Propagation and Tunnel Failure Affected by Cross-Sectional Geometry of an Underground Tunnel

Hao

Shao-hua

Jin

et al. 2019

Advances in Civil Engineering

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The process of crack propagation and tunnel failure is affected by the cross-sectional geometry of an underground tunnel. In order to quantify the effect of section shape on the process of crack propagation in deep tunnels under high ground stress conditions, a total of four physical models with two cross-sectional shapes and twelve stress levels were designed and several large-scale physical model tests were conducted. The results indicated that, when the vertical stress is 4.94 MPa, the length and depth of the cracks generated in the rock surrounding the horseshoe tunnel are about eight times that around a circular tunnel. The position where the circumferential displacement of the horseshoe tunnel begins to be stable is about two, to two and a half, times that around a circular tunnel. After the deep chamber was excavated, continuous spalling was found to occur at the foot of the horseshoe tunnel and microcracks in the surrounding rock were initially generated from the foot of the side wall and then developed upwards to form a conjugate sliding shape to the foot of the arch roof, where the cracks finally coalesced. Discontinuous spalling occurred at the midheight of the side wall of the circular tunnel after excavation, and microcracks in the surrounding rock were initially generated from the midheight of the side wall and then extended concentrically to greater depth in the rock mass surrounding the tunnel. Tensile failure mainly occurred on the surface of the side wall: shear failure mainly appeared in the surrounding rock.

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A physical and numerical investigation of the failure mechanism of weak rocks surrounding tunnels

Cited by 73 publications

References 35 publications

Study on Hysteretic Fracture of Naturally Cracked Surrounding Rock

Study on Hysteretic Fracture of Naturally Cracked Surrounding Rock

Experimental Study of the Behavior of Rectangular Excavations Supported by a Pipe Roof

Instability Process of Crack Propagation and Tunnel Failure Affected by Cross-Sectional Geometry of an Underground Tunnel

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