Progressive failure process of secondary lining of a tunnel under creep effect of surrounding rock

2019 ◽  
Vol 90 ◽  
pp. 76-98 ◽  
Author(s):  
Guowen Xu ◽  
Chuan He ◽  
Qinhao Yang ◽  
Bo Wang
Keyword(s):  
Progressive Failure ◽  
Failure Process ◽  
Surrounding Rock ◽  
Creep Effect ◽  
Secondary Lining

Numerical Analysis of Faults on Deep-Buried Tunnel Surrounding Rock Damaged Zones

2011 ◽  
Vol 90-93 ◽  
pp. 74-78 ◽  
Author(s):  
Jun Hu ◽  
Ling Xu ◽  
Nu Wen Xu
Keyword(s):  
Numerical Analysis ◽  
Mechanical Response ◽  
Progressive Failure ◽  
Process Analysis ◽  
Failure Process ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Factors Affecting ◽  
Rock Failure Process ◽  
Tunnel Instability

Fault is one of the most important factors affecting tunnel instability. As a significant and casual construction of Jinping II hydropower station, when the drain tunnel is excavated at depth of 1600 m, rockbursts and water inrush induced by several huge faults and zone of fracture have restricted the development of the whole construction. In this paper, a progressive failure progress numerical analysis code-RFPA (abbreviated from Rock Failure Process Analysis) is applied to investigate the influence of faults on tunnel instability and damaged zones. Numerical simulation is performed to analyze the stress distribution and wreck regions of the tunnel, and the results are consistent with the phenomena obtained from field observation. Moreover, the effects of fault characteristics and positions on the construction mechanical response are studied in details. Some distribution rules of surrounding rock stress of deep-buried tunnel are summarized to provide the reasonable references to TBM excavation and post-support of the drain tunnel, as well as the design and construction of similar engineering in future.

scholarly journals Study on the Damage Process and Numerical Simulation of Tunnel Excavation in Water-Rich Soft Rock

2021 ◽  
Vol 11 (19) ◽  
pp. 8906
Author(s):  
Wenqi Ding ◽  
Shi Tan ◽  
Rongqing Zhu ◽  
He Jiang ◽  
Qingzhao Zhang
Keyword(s):  
Progressive Failure ◽  
Water Immersion ◽  
Failure Process ◽  
Soft Rock ◽  
Simulation Method ◽  
Surrounding Rock ◽  
Constitutive Relationship ◽  
Water Softening ◽  
Deformation And Failure ◽  
Tensile Damage

The weakening effect is one of the most important causes triggering large deformation and failure of soft-rock engineering; however, few studies paid attention to damage evolution and constitutive relationship of rock in tensile damage in the excavation unloading and water-weakening process, not to mention the coupling process of unloading and water-weakening. In this paper, the mechanism and engineering characteristics of unloading softening and water-softening of water-rich soft rock are analyzed and summarized. Then with the aid of the strain equivalent principle, the damage of surrounding rock caused by unloading softening and water-softening is coupled, and the compression shear damage and the tensile damage of surrounding rock under the unloading process are analyzed. A damage constitutive model of rock subjected to excavation unloading and water-weakening is proposed considering the influence of water immersion time, and the proposed model is applied in a newly established finite element simulation method, which is suitable for excavation in the water-rich soft rock. Based on the mechanical-hydraulic-damage coupled method, the progressive failure process of surrounding rock under the dual softening effects can be reflected by the deteriorated parameters of damage elements. Finally, the field monitoring data of a typical section in the Xujiadi tunnel is used to verify the applicability and accuracy of the proposed dual softening model and simulation method.

Study on Stability and Anchoring Effect of Jointed Rock Mass of An Underground Powerhouse

2004 ◽  
Vol 261-263 ◽  
pp. 1551-1556
Author(s):  
S.C. Li ◽  
Wei Zhong Chen ◽  
Wei Shen Zhu ◽  
X.B. Qiu ◽  
Chien Hsin Yang
Keyword(s):  
Rock Mass ◽  
Damage Evolution ◽  
Evolution Equations ◽  
Progressive Failure ◽  
Failure Process ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Underground Powerhouse ◽  
Anchoring Effect

This present paper adopts a constitutive model for elastic damage of intermittently jointed rock mass, damage-evolution equations and a supporting model of damaged rock-bolt bar(DRBB) element to simulate effect of reinforcement. The results have indicated that the above method well describes the progressive failure process of the surrounding rock mass and the anchorage effect. The theoretical achievements are of referential value to designers.

Study of the progressive failure of concrete by phase field modeling and experiments

2021 ◽  
pp. 105678952110014
Author(s):  
Jichang Wang ◽  
Xiaoming Guo ◽  
Nailong Zhang
Keyword(s):  
Phase Field ◽  
Progressive Failure ◽  
Failure Process ◽  
Damage Model ◽  
Concrete Fracture ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Edge Notch ◽  
Modeling And Experiments ◽  
Crack Faces

In this research, experiments and numerical simulations are employed to research the failure process of concrete. Fracture experiments on three-point bending (TPB) concrete beams with a prefabricated edge notch at the middle of the beam bottom are performed using a modified rigid testing instrument. The characteristics of the crack and section are analyzed, including the crack tensile opening displacement, crack length and width, and crack faces characteristics. Also, the full curves of the force-crack tensile opening displacement (CMOD) and force-deflection of the TPB beams with the prefabricated edge notch after breakage are obtained. The phase field (PF) damage model is applied to the mixed-mode and mode-I failure processes of concrete structures through the ABAQUS subroutine user defined element (UEL). The crack path and the full curves of force-CMOD and force-deflection obtained by numerical calculations are consistent with the experimental results and the calculated results of other researchers. The influences of the mesh sizes, initial lengths, and notched depths on the TPB beam of concrete are also analyzed.

scholarly journals Deformation Characteristics of the Surrounding Rock of a Six-Lane Multiarch Tunnel under Different Excavation Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lina Luo ◽  
Gang Lei ◽  
Haibo Hu
Keyword(s):  
Three Dimensional ◽  
Class Ii ◽  
Surrounding Rock ◽  
Displacement Rate ◽  
Construction Technology ◽  
Deformation Characteristics ◽  
Highway Traffic ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Secondary Lining

Highway tunnel plays an increasingly prominent role in the development of high-grade highway traffic in mountainous countries or regions. Therefore, it is necessary to explore the deformation characteristics of the surrounding rock of a six-lane multiarch tunnel under different excavation conditions. Using the three-dimensional indoor model test and finite element analysis, this paper studies the dynamic mechanical behavior of a six-lane construction, reveals the whole process of the surrounding rock deformation process of class II surrounding rock under different excavation conditions, and puts forward the best construction and excavation method. The results show that the maximum displacement rate of excavation scheme III is the largest, and the maximum displacement rate of excavation scheme I is basically the same as that of excavation scheme II. Therefore, in terms of controlling the displacement rate of the surrounding rock, the effect of excavation scheme I is basically the same as that of excavation scheme II, while that of excavation scheme III is poor. In terms of construction technology, scheme II is simpler than scheme I and can ensure the integrity of the secondary lining. Therefore, in class II surrounding rock of the supporting project, it is recommended to adopt scheme II for construction.

Low-order mixed finite element analysis of progressive failure in pressure-dependent materials within the framework of the Cosserat continuum

2017 ◽  
Vol 34 (2) ◽  
pp. 251-271 ◽  
Author(s):  
Hongxiang Tang ◽  
Yuhui Guan ◽  
Xue Zhang ◽  
Degao Zou
Keyword(s):  
Finite Element ◽  
Strain Softening ◽  
Progressive Failure ◽  
Mixed Finite Element ◽  
Failure Process ◽  
Cosserat Continuum ◽  
Element Analysis ◽  
Content Type ◽  
Engineering Problems ◽  
Low Order

Purpose This paper aims to develop a finite element analysis strategy, which is suitable for the analysis of progressive failure that occurs in pressure-dependent materials in practical engineering problems. Design/methodology/approach The numerical difficulties stemming from the strain-softening behaviour of the frictional material, which is represented by a non-associated Drucker–Prager material model, is tackled using the Cosserat continuum theory, while the mixed finite element formulation based on Hu–Washizu variational principle is adopted to allow the utilization of low-order finite elements. Findings The effectiveness and robustness of the low-order finite element are verified, and the simulation for a real-world landslide which occurred at the upstream side of Carsington embankment in Derbyshire reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved. Originality/value The permit of using low-order finite elements is of great importance to enhance computational efficiency for analysing large-scale engineering problems. The case study reconfirms the advantages of the developed elastoplastic Cosserat continuum scheme in capturing the entire progressive failure process when the strain-softening and the non-associated plastic law are involved.

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