Sep 14, 2021 · After the excavation of a high-stress rock mass, with time, stress concentration will occur in the surrounding rock of the roadway, and stress release will occur within a certain range, making the surrounding rock suddenly suffer severe deformation and failure; this severe deformation and failure will gradually extend to the deeper parts of the surrounding rock.
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2.2. General Geological Information of the Tunnel
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In order for tunnel boring machines to efficiently cut or break rock, it is necessary that the block of rock in contact with the cutter be adequately supported by the surrounding rock mass.
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Different excavation procedures have great important influence on the stability of the surrounding rock, especially for tunnels under unsymmetrical pressure. In this paper, flac 3D is used in the simulation of different excavation sequence for Dawanggou tunnel in order to analyze the variation of plastic zones and deformation of the surrounding
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Jan 01, 2018 · In the second case (Case 2: TBM), the excavation step per cycle was simulated to 1 m to represent the excavation sequence of a 6 m diameter mechanized tunnel using a TBM. The rock mass for both cases was assumed to behave as an elasto-visco-elastic material and CVISC model within FLAC software (Itasca, 2011) was employed. As previously
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Sep 04, 2020 · In some large-scale hydroelectric power projects, there are more than 3 tunnels that are too close to each other to eliminate the mutual influence during the excavation period, especially for large-scale tunnel groups. In this paper, aimed at analyzing the Bukun hydropower station consisting of 8 tunnels in Malaysia, the displacement, stress, and plastic zone of the …
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The analysis of the magnitude and condition of the stress state in the ground mass surrounding the excavation will help to minimise project costs by optimising design. This paper will deal with application of the knowledge of stress fields surrounding the excavation to help understand the failure mechanism within the rock mass.
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The stress state of the surrounding rock mass tends to redistribute to a new balance with the following disturbing phenomena: bulking and cracking of the shotcrete layers, stress-induced fracturing, and heavy damage to the zone near the surrounding rock mass [2,3,4]. This threatens the stability of the underground caverns.
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The analysis of the magnitude and condition of the stress state in the ground mass surrounding the excavation will help to minimise project costs by optimising design. This paper will deal with application of the knowledge of stress fields surrounding the excavation to help understand the failure mechanism within the rock mass.
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Sep 13, 2021 · Based on the geological cataloging of the drilled core, the stability of the surrounding rock is determined by analyzing the integrity of the core during drilling by the RQD value. To detect and judge the effect of grouting in the ore body, the RQD value is calculated before and after grouting. The statistical results are shown in Tables 2 and 3.
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Jul 01, 2019 · Fig. 2 shows a typical variability of the parameter A, which characterises the amplification of the resistance domain with respect to the depth and to the rock mass density, ρ.. Download : Download high-res image (224KB) Download : Download full-size image Fig. 2. Example of the variation of the Hoek-Brown parameter A with depth and rock mass density, ρ.
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Mar 01, 2020 · Finally, the proposed methods are applied to Azad Pattan hydropower powerhouse excavation process. The variation of seepage field and the stability of surrounding rock during excavation are analyzed to verify the rationality of the methods practically. 2. Basic theory of unsteady seepage2.1. Formulation of unsteady seepage problems
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Sep 27, 2018 · Excavation Optimization and Stability Analysis for Large Underground Caverns Under High Geostress: A Case Study of the Chinese Laxiwa Project Excavation Sequence and Surrounding Rock Mass Stability of Large-Scale Underground Engineering with 8 Tunnels. Zhi-qiang Zhang, M.
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It describes how tunnel deforms as excavation of weak rock mass occurs. requirement for the stability of tunnels in weak rock. how a rock mass surrounding a …
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is taken timely [1]. The poor rock mass conditions leads a problem of instability for tunnel and face if the ratio of rock mass strength to in situ stress falls below 0.2 [2]. The stability may be enhanced through load transfer by the interaction of immediate support and surrounding ground conditions [3]. In order to control this type of behavior,
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Dec 24, 2021 · The diversion tunnel of a hydropower station is characterized by low quality surrounding rock and weak structural planes. During excavation, rock mass spalling and cracking frequently occur. To evaluate the stability of a rock mass during tunnel excavation, high-precision microseismic monitoring technology was introduced to carry out real-time monitoring.
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Dec 24, 2021 · The diversion tunnel of a hydropower station is characterized by low quality surrounding rock and weak structural planes. During excavation, rock mass spalling and cracking frequently occur. To evaluate the stability of a rock mass during tunnel excavation, high-precision microseismic monitoring technology was introduced to carry out real-time monitoring.
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The stress state of the surrounding rock mass tends to redistribute to a new balance with the following disturbing phenomena: bulking and cracking of the shotcrete layers, stress-induced fracturing, and heavy damage to the zone near the surrounding rock mass [2,3,4]. This threatens the stability of the underground caverns.
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Jul 01, 2019 · Fig. 2 shows a typical variability of the parameter A, which characterises the amplification of the resistance domain with respect to the depth and to the rock mass density, ρ.. Download : Download high-res image (224KB) Download : Download full-size image Fig. 2. Example of the variation of the Hoek-Brown parameter A with depth and rock mass density, ρ.
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Aiming at the large deformation instability problem caused by the excavation unloading of a coal roadway in deep-buried slowly inclined jointed rock mass, the geomechanical parameters and deformation failure characteristics of an engineering geomechanical model were investigated. The in-situ stress state of the model was measured with the stress relief method. The …
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