Coupled analytical solutions for circular tunnels considering rock creep effects and time-dependent anchoring forces in prestressed bolts

Yang, Wendong; Wang, Xuepeng; Ivanović, Ana; Zhang, Xiang

doi:10.1016/j.tust.2022.104954

Cited by 6 publications

(1 citation statement)

References 33 publications

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“…Relevant scholars have introduced the concept of damage to accurately describe the creep behavior of soft rock and have determined the relationship between creep instability and damage variables [19][20][21][22][23][24][25][26]. Due to the lack of coupling between the support structure and the surrounding rock in terms of strength, stiffness, and deformation, some scholars [27][28][29][30] suggest that the key sections of the roadway's surrounding rock should be reinforced using bolt-mesh-cable coupling support technology. Alternatively, they propose establishing a model that considers the anchoring force of bolts and the deformation of the rock mass to accurately describe the creep failure of the roadway.…”

Section: Introductionmentioning

confidence: 99%

Creep Instability Mechanism and Control Technology of Soft Coal Roadways Based on Fracture Evolution Law

Wu,

Gu,

Zhang

et al. 2023

Applied Sciences

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To address the challenging issues of large deformation, control difficulties, and susceptibility to failure in the support structure of soft coal roadways, this study utilizes the CVISC block creep model in UDEC software. The model incorporates Coulomb slip without cohesive contact to simulate the characteristics of soft coal, such as its loose, fragile, and small-block nature. Additionally, a soft coal nonlinear discrete element creep model is developed to investigate the creep characteristics of soft coal under triaxial compression, with the aim of revealing the underlying creep destabilization mechanism in soft coal tunnels. Based on the research findings, a primary, strong active support technology is proposed. This approach involves the use of high-preload, high-strength anchor rods and anchor cables, as well as the implementation of steel mesh and plastic woven mesh to enhance surface protection. The study highlights that: (1) The shear cracks inside the coal body of the soft coal specimen transform into tensile cracks under external force, leading to an increase in the number of tensile cracks. This is an important symbol of accelerated creep in soft coal. Improvement in peripheral pressure helps inhibit the generation of tensile cracks inside the specimen. (2) The rapid development of creep and inter-particle tensile fissures within the coal body particles themselves, along with the change in stress state after the excavation of the roadway, are the main reasons for the overall creep damage of the roadway. (3) The support force in the early stage of shed cable support is small, which cannot inhibit the accelerated development of tensile fissures. This leads to continuous deformation of the roadway, resulting in the failure of the support structure in the later stage and aggravated roadway damage. (4) The new support technology helps control surface deformation by enhancing the strength of the roadway protection surface. This suppresses the development speed and number of tensile fissures during roadway deformation, improves the starting strength of the roadway for accelerated creep, and enables effective control of the overall deformation of the soft coal roadway. Thus, the effectiveness of roadway support is remarkable.

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