Experimental investigation of surrounding-rock anchoring synergistic component for bolt support in tunnels

Liu, Shaowei; He, Deyin; Fu, Mengxiong

doi:10.1016/j.tust.2020.103531

Cited by 20 publications

(11 citation statements)

References 25 publications

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“…The developed layered structure will intensify the inhomogeneity of the surrounding rock stress on both sides, resulting in the asymmetric distribution of deformation and cracking on both sides. In addition, the layered structure of the surrounding rock had a sliding and separating trend along the joint surface under the force of high geostress, which aggravated the risk of surrounding rock deformation and lining cracking (Liu et al, 2020b;Zhang et al, 2022e;Li et al, 2022).…”

Section: Layered Joint Structurementioning

confidence: 99%

Study of the disaster-causing mechanism and reinforcement measures for soft rock deformation and lining cracking

Shi

Zhou

et al. 2023

Front. Earth Sci.

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Underground engineering construction is facing increasingly complex geological conditions and engineering challenges, such as surrounding rock deformation and lining cracking, that seriously threaten the safety of tunnel construction and operation. Aiming at these problems, a pipeline tunnel crossing jointed expansive mudstone strata was taken as an example, and the disaster characteristics of surrounding rock and lining were analyzed through field investigation. The disaster-causing mechanism and corresponding control measures were studied through laboratory tests and numerical simulations, which were then applied to actual construction. Meanwhile, the deformation and stress response of the surrounding rock and tunnel structure were analyzed and investigated through monitoring and numerical data. The results showed that the vault settlement and horizontal convergence deformation of surrounding rock were reduced by 64.69 mm and 54.74 mm, respectively, under the improved construction scheme. The maximum surrounding rock stress was 430.26 kPa under the improved construction scheme, which was 18.15% lower than the original stress. The maximum axial force of the steel arch frame was 33.02 kN, ensuring the stability of the supporting structure and tunnel construction safety. Finally, the rationality and effectiveness of the reinforcement measures adopted were assessed.

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Section: Layered Joint Structurementioning

confidence: 99%

Study of the disaster-causing mechanism and reinforcement measures for soft rock deformation and lining cracking

Shi

Zhou

et al. 2023

Front. Earth Sci.

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“…By comparing the characteristic curve of the surrounding rock with or without bolt support, the bolt achieved good control of the deformation of the surrounding rock. Liu 11 developed an anchoring cooperative component group to optimize the bolt anchoring structure and improve the bolt anchoring capacity to control the surrounding rock deformation. Mohammad Mohammadi 12 established the mathematical theory of the bolt support mechanism using the bolt support coefficient, which provided a new theoretical basis for explaining the bolt support effect, and defined the anchorage reinforcement capacity of a given rock mass using the discontinuity parameters in the Q-system.…”

Section: Introductionmentioning

confidence: 99%

Primary support optimization of large-span and shallow buried hard rock tunnels based on the active support concept

Liu

et al. 2022

Sci Rep

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Considering the large-span underground excavation subway station of Qingdao Metro Line 6 of China for analysis, it is necessary to optimize the traditional support system by investigating relevant codes and other tunnel projects. Based on the active support concept, a high prestressed rock bolt support system is proposed, and the optimization direction is defined to apply a high prestress force to rock bolts, increasing the appropriate spacing between supporting arches and strengthening support at key parts such as the large arch foot area, sidewalls and junctions. Numerical calculations and field monitoring are performed to analyze and evaluate the new support system. Numerical simulation results show that the new support system can effectively improve the stress state of the surrounding rock; the tensile stress area markedly decreases in size or disappears; and the plastic area also decreases in size. Field monitoring results show that the settlement of the arch crown is concentrated at 2–5 mm and the deformation rates are less than 0.5 mm/day. The supporting arches, shotcrete and rock bolts are all less than the yield strength and a high safety reserve. These results verify the safety and rationality of the proposed support system, which can be used as a reference for similar projects.

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“…As a result, the roadway is prone to nonlinear large deformation, which leads to the rock burst, coal and gas outburst, or other dynamic disasters in serious cases [2][3][4]. The instability events still occur in coal mines even when measures were implemented in the field, including increasing support strength and repairing large deformed roadway more times [5][6][7][8]. Hence, how to effectively control the deep roadway stability is still a major issue that affects the safety of recovering the deep coal resources [9].…”

Section: Introductionmentioning

confidence: 99%

Impact of Depressurizing Boreholes on Energy Dissipation in Deep Roadway

Wang

et al. 2022

Geofluids

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Depressurizing borehole drilling is an effective approach to control the large deformation of deep roadway. It can transfer the high stress in the proximity of the roadway into the deep stable rock masses. However, it should be noted that the borehole drilling will inevitably cause the secondary damage to roadway. To determine the parameters of depressurizing boreholes, the degree of the secondary damage must be evaluated properly. Given that the rock mass failure is an unstable phenomenon driven by energy, it is of great use to reveal the disturbing impact of depressurizing boreholes on the roadway stability from the angle of energy dissipation. This is much more consistent with the failure nature of rock mass. Hence, an integrated method of laboratory test, numerical simulation, and theoretical analysis was used to study the disturbing effect of depressurizing boreholes on roadway energy dissipation. The equations of elastic energy and dissipated energy of rock cell grid were derived based on the energy principle and finite-difference algorithm, which was implemented into FLAC3D software by the FISH language. The numerical stress-strain and dissipated energy-strain curves of rock samples were verified by experimentally obtained data, and the whole deformation path from roadway excavation to instability was back-analyzed by the dissipated energy evolution. Based upon the energy model, the ratio of borehole diameter D to row spacing R ( D / R ) was selected as the variable to analyze the influence of borehole parameters on the depressurizing effect. The varying D / R leads to three depressurizing states: insufficient depressurization, sufficient depressurization, and overdepressurization. Increasing D / R will make the roadway transfer from insufficient depressurization to sufficient depressurization and finally to overdepressurization. The sufficient depressurizing state could be realized by adjusting the borehole D / R value, which is of great use to the roadway control. The D / R values of 1 : 6 to 1 : 2 were proposed for the test roadway, and D / R = 1 : 6 was applied in the field test, which achieved a well roadway control effect.

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Experimental investigation of surrounding-rock anchoring synergistic component for bolt support in tunnels

Cited by 20 publications

References 25 publications

Study of the disaster-causing mechanism and reinforcement measures for soft rock deformation and lining cracking

Study of the disaster-causing mechanism and reinforcement measures for soft rock deformation and lining cracking

Primary support optimization of large-span and shallow buried hard rock tunnels based on the active support concept

Impact of Depressurizing Boreholes on Energy Dissipation in Deep Roadway

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