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An investigation on the effect of high energy storage anchor on surrounding rock conditions.

ABSTRACT: High pre-tension bolt is an effective strata control technique and is the key to ensure the stability of anchorage and roadway. Based on the performances of high energy storage tension rock bolts in different rock properties, this study proposed a constitutive model to describe the energy balance of anchor under uniaxial compression. UDEC was used to simulate the behaviour of anchor in coal under uniaxial compression and the results were analysed to study the rock mechanical properties, degree of damage and energy evolution. Simulation results showed that tension rock bolts can improve the mechanical properties and energy storage capacities of the anchor. The energy evolution was divided into three stages: (i) the external work was stored in the form of elastic strain energy (Ue ) in the anchor prior to the yielding strength; (ii) the elastic strain energy reached its maximum near the peak strength; (iii) energy was dissipated from fracture friction (Wf) , plastic deformation (Wp ) and acoustic emission (Ur ) during post-peak stage. The installation of tension rock bolts was more suitable for medium hard rock (e.g. sandy mudstone), whereas it was not effective for hard rock (e.g. sandstone).

SUBMITTER: Wu B

PROVIDER: S-EPMC7657924 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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An investigation on the effect of high energy storage anchor on surrounding rock conditions.

Wu Bowen B Wang Xiangyu X Bai Jianbiao J Wu Wenda W Meng Ningkang N Lin Huasheng H

Royal Society open science 20201007 10

High pre-tension bolt is an effective strata control technique and is the key to ensure the stability of anchorage and roadway. Based on the performances of high energy storage tension rock bolts in different rock properties, this study proposed a constitutive model to describe the energy balance of anchor under uniaxial compression. UDEC was used to simulate the behaviour of anchor in coal under uniaxial compression and the results were analysed to study the rock mechanical properties, degree o ...[more]

PMID: 33204469

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Project description:To address the problem of large deformations in weak surrounding rock tunnels under high ground stress, which cause damage to initial support structures, this study proposes a novel type of circumferential pressure-relief joint based on the concept of relieving deformation pressure of the surrounding rock. Key parameters of the pressure-relief joint, such as initial bearing capacity peak, constant bearing capacity, and allowable pressure-relief displacement, were obtained through numerical simulations and laboratory experiments. A comparison was made between the mechanical characteristics of rigid joints and the new type of pressure-relief joint. The applicability of the pressure-relief joint was verified through field tests, monitoring the surrounding rock pressure, internal forces in the steel frames, and the convergence displacement of the support structure. The results show that: (1) In the elastic stage, the stiffness of the new pressure-relief joint is similar to that of rigid joints. In the plastic stage, rigid joints fail directly, whereas the pressure-relief joint can control deformation and effectively release the deformation pressure of the surrounding rock while providing a constant bearing capacity. (2) The right arch foot in the experiment had poor rock quality, leading to high stress in the steel frame and significant horizontal displacement. After the deformation of the pressure-relief joint, the stress in the surrounding rock and steel frame significantly reduced, and the rate of horizontal deformation of the support structure slowed down. (3) The vertical and horizontal final displacements of the pressure-relief joint in the experiment were 61mm and 15mm, respectively, which did not exceed the allowable deformation values. The components of the support structure remained intact, ensuring safety. However, this study has limitations: the design of the new pressure-relief joint only allows for a vertical deformation of 150mm and a horizontal deformation of 50mm, limiting the range of pressure-relief deformation.

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An investigation on the effect of high energy storage anchor on surrounding rock conditions.

Publications

An investigation on the effect of high energy storage anchor on surrounding rock conditions.

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