Introduction

Amadei, Bernard; Stephansson, Ove

doi:10.1007/978-94-011-5346-1_1

Cited by 11 publications

(9 citation statements)

References 19 publications

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“…Through the aforementioned inversion calculations, the normal and shear stresses in the rock mass were obtained. According to Zoback [22] and Amadei [23], if we can obtain the six stress components (σ x , σ y , σ z , τ xy , τ yz , τ xz ) of the in situ stress field in the xyz coordinate system, the principal stresses (both magnitude and orientation) of the stress field could be indirectly calculated. In this study, based on the principles of elasticity and previous research [24,25], the formulae for calculating the principal stresses (σ 1 , σ 2 , σ 3 ) and the direction cosines (l x , m y , n z ) were derived as described below.…”

Section: Distribution Of the Stresses Around The Tunnelmentioning

confidence: 99%

The Inversion Method Applied to the Stress Field around a Deeply Buried Tunnel Based on Surface Strain

Yan,

Hao,

Yang

et al. 2023

Applied Sciences

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To identify the magnitude and direction of in situ stress in deeply buried tunnels, an inversion method for the stress field was proposed based on a finite number of measurement points of surface strain. Firstly, elastic strain data of finite points on the surface of tunnel surrounding rock were acquired using the borehole stress relief method at the engineering site. Secondly, a finite element model of the tunnel surrounding rock with plastic damage was established, and the parameters of the finite element model were substituted using the SIGINI subroutine. Then, an improved Surrogate Model Accelerated Random Search (SMARS) was developed using genetic algorithm programming on the MATLAB™ platform to invert and attain the globally optimal boundary conditions. Finally, the obtained optimal boundary conditions were applied to the numerical model to calculate the stress distribution in the engineering site. The reliability of this method was validated through a three-dimensional example. The method has been successfully applied to the stress-field analysis of deep tunnels in Macheng Iron Mine, Hebei Province, China. The research results show that this method is a low-cost, reliable approach for stress-field inversion in the rock around a tunnel.

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Section: Distribution Of the Stresses Around The Tunnelmentioning

confidence: 99%

The Inversion Method Applied to the Stress Field around a Deeply Buried Tunnel Based on Surface Strain

Yan,

Hao,

Yang

et al. 2023

Applied Sciences

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“…Previous studies' results have shown that in areas with mild tectonic action, the average horizontal principal stress in coal rock strata is basically proportional to the elastic modulus of the coal rock mass. The larger the elastic modulus, the higher the horizontal stress [28][29][30][31][32]. Due to the fact that in situ stress measurement in coal mines is generally carried out in relatively complete and hard or shaly sandstone, the horizontal stress values present in coal seams could be estimated based on the elastic modulus ratio.…”

Section: Test Programme 231 Determination Of Confining Pressurementioning

confidence: 99%

True Triaxial Test and Research into Bolting Support Compensation Stresses for Coal Roadways at Different Depths

Yang,

Lin,

Jiang

2023

Processes

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During the excavation and support construction process used in coal mine roadways, the stress path is the unloading of in situ stress and the compensation of support stress. The 150 mm × 150 mm × 150 mm coal mass samples were obtained in situ underground and prepared, the true triaxial loading–unloading–confining pressure restoring test method was used, and the mechanical response and deformation failure evolution characteristics of the coal seam during the excavation and support process of the shallow, medium depth, and deep coal roadways in the coal mine were simulated and studied. Based on the distribution law of the bolt and cable support stress field, the support compensation stress required for the stability of the surrounding rock after the excavation of the coal roadway with different burial depths was determined, and the corresponding roadways’ surrounding rock control technologies were proposed. This study’s results indicate that the compensation stress required for support in shallow coal roadways (with a burial depth of about 200 m) was much less than 0.1 MPa. A single rock bolt support can keep the surrounding rock of the roadway stable; the compensation stress required for support in the medium buried coal roadway (with a depth of about 600 m) is around 0.1 MPa, and the combined support of rock bolts and cables can meet the support requirements. Deep coal roadways under high stress (with a depth of about 1000 m) require support to provide compensation stress. Even if the compensation stress reaches 0.2 MPa, the surrounding rock of the roadway will experience varying degrees of creep. In this study, it was necessary to increase the support density and surface area of rock bolts and cables, the pre-tension forces of rock bolts and cables were improved, and in synergy with grouting modification, destressing and other technologies could control the large deformation of the surrounding rock of the roadway in 1000 m deep coal mines. This study’s results provide a theoretical basis for the selection of control technologies for use in coal roadways at different depths.

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“…The present-day stress has an impact on the waterflooding development, the well pattern deployment, subsurface fracture conservation, and hydraulic fracturing (Zeng and Tian, 1998). The maximum horizontal stress orientation is generally determined via hydraulic fracturing, borehole breakouts, differential strain analysis, and induced fractures during drilling (Amadei and Stephansson, 1997; Bell and Bachu, 2003; Brudy et al., 1997; Li and Zhang, 1997; Zoback and Haimson, 1983). According to the borehole breakout data, the direction of the maximum horizontal principal compressive stress was determined to be NE–SW in most areas and E–W in some areas of the Huanghua depression (Figure 3).…”

Section: Data and Materialsmentioning

confidence: 99%

An approach for determining the water injection pressure of low-permeability reservoirs

Lyu

Zeng

Chen

et al. 2018

Energy Exploration & Exploitation

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Waterflooding is an important functional process for low-permeability reservoir development. However, production practice shows that water breakthrough and floods along natural fractures are ubiquitous in low-permeability reservoirs. Therefore, controlling the water injection pressure to prevent water breakthrough and floods along natural fractures is an effective measure for improving the waterflooding development effect. In this paper, an approach is proposed for determining the water injection pressure based on the opening pressure of natural fractures in fractured low-permeability reservoirs. The opening pressures of natural fractures calculated by the analytical method in the paper and the formation-parting pressures are compared based on the production performance in two different fault blocks F16 and Z3 of the Zhouqingzhuang Oilfield in the Bohai Bay Basin, China. The results show that the calculated opening pressures of the natural fractures in fault blocks F16 and Z3 are 31.4 and 42.9 MPa, respectively, and they are close to the opening pressures of natural fractures obtained from the step-rate tests in injection wells (28.6 and 41.1 MPa); whereas, the formation-parting pressures (44.5 and 47.6 MPa) are greater than the opening pressures of natural fractures. This suggests that the opening pressures of natural fractures can be used, instead of the formation-parting pressure, for the maximum threshold of the water injection pressure. Its effectiveness has been confirmed via comparison to the production performances of the other two wells in the Zhouqingzhuang Oilfield and

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Introduction

Cited by 11 publications

References 19 publications

The Inversion Method Applied to the Stress Field around a Deeply Buried Tunnel Based on Surface Strain

The Inversion Method Applied to the Stress Field around a Deeply Buried Tunnel Based on Surface Strain

True Triaxial Test and Research into Bolting Support Compensation Stresses for Coal Roadways at Different Depths

An approach for determining the water injection pressure of low-permeability reservoirs

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