Tangent modulus method – An original method to measure in-situ rock stress

Fujii, Yoshiyuki; Makasi, M.; Kodama, Junichi; Fukuda, Daisuke; Goto, Kenta; Kumakura, Satoshi; Kanaoka, Masanobu; Dassanayake, Anjula Buddhika Nayomi

doi:10.1016/j.tust.2018.08.005

Cited by 9 publications

(2 citation statements)

References 10 publications

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“…stress value of the bending point in the first loading cycle of the stress-tangent modulus curve is considered as the normal component of the in-situ rock stress along the drilled direction of the specimen (Fujii et al, 2018).…”

Section: Othersmentioning

confidence: 99%

Untitled

2022

MGPB

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Knowledge of in-situ rock stress is one of the significant issues in many engineering problems. There are various methods for determining in-situ stress. Most of the common methods used for the determination of in-situ stress are time and cost consuming, and in many cases need specific accessibility. Therefore, attention to core-based methods is increasing. One of these methods is the acoustic emission technique based on the Kaiser effect. This method is among the stress stressing-destressing methods and is based on observing rock behaviour without having any important impact on it. Knowledge of the acoustic emission principles and acoustic signal parameters is the first step to use the Kaiser effect method for in-situ stress determination. Also, using the Kaiser effect method requires knowledge on the mechanism and theory associated with the Kaiser effect. In this research, different methods for determining the Kaiser effect in parametric (tangent method and maximum slope, etc.) and signal processing (Fourier transform, wavelet transform, etc.) terms were reviewed. The results obtained from the Kaiser effect method were compared to other common methods used for in-situ stress measurement, like over-coring and hydraulic fracturing methods, and based on the results, there was a good agreement between them. Also, the effective parameters on determining the Kaiser effect stress point were investigated. The important parameters were the testing procedure, confining pressure, physical properties of rock, delay time and retention time, direction and amount of loading, anisotropy angle and loading rate.

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Section: Othersmentioning

confidence: 99%

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2022

MGPB

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“…Therefore, to ensure the safe construction of the tunnel, it is necessary to test the initial ground stress in the construction area before the construction of large-scale projects such as the tunnel. In most cases, on-site measuring methods, such as the mechanical and vibrating wire load sensors, the hydraulic fracturing and so on, are one of the most advanced and effective methods to obtain the initial ground stress [2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Inversion and Analysis of the Initial Ground Stress Field of the Deep-Buried Tunnel Area

Tan

Gao

et al. 2022

Applied Sciences

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The detailed analysis of the initial ground stress distribution law is an important work for the safety of tunnel construction and operation. Especially, the high ground stress phenomenon in the deep-buried tunnel area is common, which has a great impact on the tunnel construction. Based on the on-site measured ground stress data, the analysis of the initial ground stress field by numerical simulation and multiple linear regression is mainly described in this study. Following the comparison and selection of three coefficient estimation methods for the regression equation, the best regression method is selected for inversion and verification. The distribution characteristic of the initial ground stress at different buried depths of the tunnel line is obtained. The inversion results of the initial ground stress in a tunnel area, in China, show that the lateral pressure coefficient gradually decreases with the buried depth increasing, while the overall lateral pressure coefficient is in the range of 1.0–2.0, showing a more significant horizontal tectonic. At the area where the tunnel passes through the fault, a small amount of horizontal tectonic stress is released. The ratio of horizontal principal stress to vertical principal stress is smaller than that on both sides, which is different from the distribution characteristic of lateral pressure coefficient without the impact of fault. It shows that faults have a great influence on ground stress. The lateral pressure coefficient in the area near the fault must be determined according to the on-site measured results.

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Secant Modulus Method: A Simplified Technique for Measuring in Situ Stresses in Rocks

Ali,

Karakus,

Nguyen

et al. 2024

Rock Mech Rock Eng

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The core of sustainable mining is the preservation of the ground stability, and in situ stress measurement is crucial as most of the stability issues are directly associated with the in situ and induced stresses. Deformation rate analysis and acoustic emission are reliable and low-cost methods of stress measurement leveraging stress memory in rocks. However, owing to rock heterogeneity and complex geological stress history, the accurate determination of in situ stresses is often challenging. This study proposes a simple, accurate, and improved method for determining the in situ stresses in rocks called the Secant Modulus Method (SMM). The effectiveness of SMM is determined through uniaxial cyclic loading and unloading experiments on different types of soft and hard crystalline rocks. The influence of the loading modes, strain rates, and time delay is also investigated. Additionally, its utility for in situ stress measurement is explored. The SMM method proved effective in determining both applied and in-situ stresses, with no effect from variations in loading conditions, loading rates, and time delays. Moreover, the in situ stresses measured using the SMM were in good agreement with the overcoring method.

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Tangent modulus method – An original method to measure in-situ rock stress

Cited by 9 publications

References 10 publications

Untitled

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Inversion and Analysis of the Initial Ground Stress Field of the Deep-Buried Tunnel Area

Secant Modulus Method: A Simplified Technique for Measuring in Situ Stresses in Rocks

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