Mechanism of core discing in the relaxation zone around an underground opening under high in situ stresses

An, Lijia; Jin, Changyu; Li, Dong; Ding, Chenggong; Dai, Xinghang

doi:10.1007/s10064-017-1168-3

Cited by 12 publications

(3 citation statements)

References 11 publications

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“…Current research also supports this view. Underground tunnels or caverns with relatively intact surrounding rock often possess higher strength and have a relatively lower probability of experiencing water inrush or similar geological disasters. , Additionally, Δ V demonstrates a declining trend under stable water supply under relative lower σ 2 . However, when the increase in σ 2 becomes more significant (such as σ 2 = 30, 35 MPa in this study), σ cd and σ 1,peak of the cracked rock start to decline, resulting in a decrease in rock strength and heightened development of internal water inrush channels in the cracked rock.…”

Section: Discussionmentioning

confidence: 99%

Experimental Study on the Response of Cracked Sandstone to the Intermediate Principal Stress Coupled with Pore Pressure

Liang,

Huang,

Zheng

et al. 2024

ACS Omega

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Underground fractured rock masses are susceptible to failure under the combined influence of true triaxial stresses and pore pressure, posing severe threats to personnel and production safety of underground engineering. To investigate the influence of intermediate principal stress (σ 2 ) on the mechanical and water diffusion volume change (ΔV) characteristics during the failure process of cracked rocks under stable pore pressure, this study conducted true triaxial strength experiments on cracked sandstone with stable pore pressure. The results demonstrated that with the increase of σ 2 , crack initiation stress (σ ci ), crack damage stress (σ cd ) and the peak stress (σ 1,peak ) of cracked sandstone initially increase and then decrease. Conversely, ΔV tends to decrease first and then increase with the increase of σ 2 . This inverse relationship indicates that under elevated σ 2 , the decreased strength of cracked rock could lead to an increase in ΔV, which may increase the probability of water inrush disasters. The findings of this study provide a theoretical reference for the stability of rock mass engineering and the prevention of water inrush disasters.

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Section: Discussionmentioning

confidence: 99%

Experimental Study on the Response of Cracked Sandstone to the Intermediate Principal Stress Coupled with Pore Pressure

Liang,

Huang,

Zheng

et al. 2024

ACS Omega

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“…Line b is located inside the rock mass and is not visible; thus, it cannot be measured directly. In order to accurately estimate the thickness of the unstable surrounding rock, a coring survey method is adopted [27][28][29][30][31]. The same section is selected for the coring survey and laser ranging, but it is more difficult and time-consuming to acquire high-density coring survey points compared to performing laser ranging, and the detection accuracy is limited.…”

Section: Determination Of the Geometric Model Parameters Of Sdmmentioning

confidence: 99%

Establishment and Application of the Spatial Decomposition Method (SDM) for Tunnels Passing Through Large Karst Caves

et al. 2020

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Karst tunnels commonly pass through large karst caves during their construction and operation. Although treatment technologies are relatively mature, a systematic treatment method to guide the selection of treatment technologies is lacking. To solve this problem, a spatial decomposition method (SDM) of large karst caves is proposed that is based on analyzing the spatial relationship between tunnels and karst caves and summarizing the relevant treatment techniques. In this method, the space between the tunnel and the cavern is divided into eight parts using a space dividing line (SDL), which makes the spatial position relationship between the tunnel and cavern more intuitive. A geometric model of the SDM is established, and the numerical values of each geometric parameter are determined by field surveys and drawings. Constructing a three-dimensional spatial diagram by applying relevant parameters to the geometric model provides a reference for selecting a treatment technology. The SDM of the arch top, arch bottom, and two wings matching the treatment technology is proposed. Seven principles of technical selection—namely, safety, convenience, scientificity, sustainability, economy, feasibility, and openness—are mentioned in order to overcome the difficulty of technology selection due to such factors as technological diversity, materials, equipment, and environment. Finally, the SDM is used to solve the problem of the Shangyuan tunnel passing through a large karst cave. The implementation of the SDM in tunnel construction would represent a significant breakthrough and has important engineering value in solving the problem of tunnel passes through large karst caves.

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“…A D-shaped cross section tunnel exhibits spalling failure under high static stress conditions [20]. With increasing depth of underground space exploitation, core discing occurs not only in highly stressed intact rock but also in the relaxation zone of the surrounding rock masses [21]. In a coal mine, the increase in permeability can be attributed to shear failure of coal due to decreased deviator stress resulting from in situ stress redistribution [22].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Stress Relaxation of Yunnan Sandstone

Zheng

2022

Lithosphere

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This study presents the results from five relaxation tests conducted under uniaxial compression at room temperature. Test specimens were from sandstone formations at a mine, in Yunnan, and exhibited brittle failure. The test apparatus was valid for conducting stress relaxation experiments on sandstones by theoretical model and deformation measurements. Multiple load levels were applied in steps to each specimen, with each displacement level maintained for 12 d or longer. As soon as axial stress was decreased, it stabilized at an almost constant value after 12–24 h. Three distinct relaxation phases were observed to exist at all displacement levels except the specimen 3 in all tests. Based on the LM-NLSF method, model parameters under different strain levels were obtained. Comparison of test curves with theoretical curves showed that the Burgers model, which considers damage, was suitable for describing the stress relaxation properties of sandstones and the obtained parameters had a certain practical value.

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Mechanism of core discing in the relaxation zone around an underground opening under high in situ stresses

Cited by 12 publications

References 11 publications

Experimental Study on the Response of Cracked Sandstone to the Intermediate Principal Stress Coupled with Pore Pressure

Experimental Study on the Response of Cracked Sandstone to the Intermediate Principal Stress Coupled with Pore Pressure

Establishment and Application of the Spatial Decomposition Method (SDM) for Tunnels Passing Through Large Karst Caves

An Experimental Study on Stress Relaxation of Yunnan Sandstone

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