scholarly journals Influence of the Variability of Compressed Air Temperature on Selected Parameters of the Deformation-Stress State of the Rock Mass Around a CAES Salt Cavern

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6197
Author(s):  
Krzysztof Polański
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Compressed Air ◽  
Influence Of Temperature ◽  
Salt Cavern ◽  
Working Cycle ◽  
Salt Creep ◽  
Deformation Stress ◽  
The Stability ◽  
The Impact

The article presents the results of a numerical simulation of the deformation-stress state in the rock mass around a salt cavern which is a part of a CAES installation (Compressed Air Energy Storage). The model is based on the parameters of the Huntorf power plant installation. The influence of temperature and salt-creep speed on the stability of the storage cavern was determined on the basis of the three different stress criteria and the effort of the rock mass in three points of the cavern at different time intervals. The analysis includes two creep speeds, which represent two different types of salt. The solutions showed that the influence of temperature on the deformation-stress state around the CAES cavern is of importance when considering the stress state at a distance of less than 60 m from the cavern axis (at cavern diameter 30–35 m). With an increase in cavern diameter, it is possible that the impact range will be proportionately larger, but each case requires individual modeling that includes the shape of the cavern and the cavern working cycle.

Stability Analysis about the Impact of Soft Rock to the Underground Cavern Group

2013 ◽  
Vol 706-708 ◽  
pp. 560-564
Author(s):  
Yi Huan Zhu ◽  
Guo Jian Shao ◽  
Zhi Gao Dong
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Stability Analysis ◽  
Soft Rock ◽  
Element Model ◽  
Underground Excavation ◽  
Power Station ◽  
Excavation Process ◽  
The Stability ◽  
The Impact

Soft rock is frequently encountered in underground excavation process. It is difficult to excavate and support in soft rock mass which has low strength, large deformation and needs much time to be out of shape but little time to be self-stabilized. Based on a large underground power station, finite element model analysis was carried out to simulate the excavation process and the results of displacement, stress and plasticity area were compared between supported and unsupported conditions to evaluate the stability of the rock mass.

scholarly journals Investigating the variation of the fields of elastic stresses in the rock mass when developing the Peschanskoye deposit

2020 ◽  
pp. 19-28
Author(s):  
Lipin Iakov ◽  
◽  
Sentiabov Sergei ◽  
Krinitsyn Roman ◽  
◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Rock Burst ◽  
Extreme Values ◽  
Rockburst Hazard ◽  
Elastic Stresses ◽  
Ore Bodies ◽  
Study Parameter ◽  
State Variation ◽  
The Impact

Research aim is to study parameter variations in the stress state of the rock mass to ensure safe and efficient mining of the Peschanskoye magnetite deposit (Northern Ural) to the full depth, which has been carried out by Severopeschanskaya mine since 1958 in a complex of hard rock at a depth of 200 to 700 m. Blind, thick, and steep ore bodies are developed by a block-caving method with ore breaking to a clamped medium. From a depth of 400 m, the field is classified as rock burst hazardous. The first rock burst was recorded in 1981 at a depth of 450 m. Research methodology includes full-scale experimental measurements of the rock and ore mass stress state at accessible depths and horizons of the deposit, establishing patterns of stress growth with depth, as well as long-term (since 1990) geo-deformational monitoring of an untouched rock mass stress level in time. Research results analysis has allowed to establish the patterns in stress-strain state changes during mining. Gradients of gravitational and tectonic stresses growth with depth are determined. Alternating (astrophysical) stresses are highlighted in a special line, the extreme values of which are linked chronologically with various information factors. Conclusions. The determined values of rock mass natural stress state variation parameters in combination with the established stresses around the workings and goafs (technogenic impact) make it possible to take into account the main tempo-spatial factors of the impact made by the mentioned loads when selecting rockburst-safe and effective mining parameters for underground geotechnology both at the top horizons when applying controlled collapse of overlying blind deposits and in the prevention of rockburst hazard in the lower horizons of the developed field

A Study on Stability of Expressway Tunnel Surrounding Rock Containing Weak Intercalated Rock

2010 ◽  
Vol 168-170 ◽  
pp. 2543-2547
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Rock Mass ◽  
Plastic Zone ◽  
Surrounding Rock ◽  
Constitutive Law ◽  
Numerical Tests ◽  
Stability Of Surrounding Rock ◽  
Strain Type ◽  
Deformation Stress ◽  
Plain Strain ◽  
The Stability

Weak intercalated rock plays an important role in the stability of engineering rock mass. It controls the mechanism of deformation and breakage of rocks. Systematic numerical tests have been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock has been analyzed by the FEM software ABAQUS. All of the numerical modelings are plain-strain type with elasto-plastic constitutive law and Drucker-Prager failure criterion. Some quantificational results about the influence of weak intercalated rock are summarized, especially the influence on the deformation, stress of surrounding rocks and plastic zone. Because of weak intercalated rock, the stress of surrounding rock appears the character of discontinuity. In addition, the distribution of plastic zone is also affected. When weak intercalated rocks exist in vault, spandrel and bottom, the situation of surrounding rock is comparatively unfavorable. These results have a certain role in guiding significance to the site selection and layout, the majorization of supporting system and the construction of tunnel of the same kind.

scholarly journals Analysis of rock mass behavior with Empirical and Numerical method for the construction of diversion tunnel, Laos

2022 ◽  
Vol 1212 (1) ◽  
pp. 012028
Author(s):  
D J W Mboussa ◽  
S Sun
Keyword(s):  
Numerical Modeling ◽  
Rock Mass ◽  
Field Investigation ◽  
Geological Strength Index ◽  
Rock Masses ◽  
Mountain Area ◽  
Diversion Tunnel ◽  
The Stability ◽  
The Cost ◽  
The Impact

Abstract Tunneling construction in the mountain area is a challenge for engineers and geotechnicians because of instability due to the presence of discontinuities. The objective of this paper is the modeling of surrounding rock masses for the stability of the diversion tunnel to predict the behavior of rock masses during the excavation process for the Nam Phoun hydropower station project in Laos. Field investigation and laboratories test was realized; Empirical methods as Rock mass designation and Geological Strength Index were performed, rock masses were classified in three categories (RM-1, RM-2, and RM-3); in situ stresses were obtained from existing equations, numerical modeling was performed by the 2D plane strain finite element code Phase2 developed by Rocscience, using Generalized Hoek-Brown criterion for each type of rock masses. The results of numerical modeling show the strength zones of stresses and deformations around the tunnel and predict the instabilities around the tunnel during excavations processes. Thus, for all rock’s masses, it will be necessary to consider an analysis for the supports design before the excavation’s process. The findings of this study allow a clearer understanding of the importance to assess a predictive analysis of slope stability during the feasibility phase of a project by engineers to have an idea of instabilities and its significant in preventing the impact on the cost of the project.

scholarly journals Analysis of Stress-Strain States in the Vicinity of Mining Excavations in a Rock Mass with Variable Mechanical Properties

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5567
Author(s):  
Marek Jendryś ◽  
Stanisław Duży ◽  
Grzegorz Dyduch
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Numerical Simulations ◽  
Mechanical Parameters ◽  
Mining Operations ◽  
Axial Forces ◽  
Internal Forces ◽  
Random Variability ◽  
The Stability ◽  
The Impact

Rock mass is a medium created through processes that have lasted over four billion years, and its intrinsic feature is the variability of the parameters that describe it. A particularly high variability of mechanical parameters is observed in Carboniferous sedimentary and metamorphic rocks. The mechanical properties, especially the rock mass strength, are essential for the design and maintenance of the stability of excavations conducted in it and for the safe conduct of mining operations. This article presents the test results confirming the random variability of the mechanical parameters of the rock mass. The second part of the article presents the results of numerical simulations mapping the Carboniferous rock mass along with a 1000 m deep tunnel excavation protected by steel arch supports. Numerical simulations were carried out for models with different variability coefficients of strength and deformation parameters, and the obtained results were analyzed in terms of damage zones and rock mass stress state as well as axial forces in the modelled supports. The results of the simulation demonstrate the impact of the variability of rock mass properties on its state in the vicinity of the excavation and, consequently, on the internal forces in the steel supports and their uneven loading along the length of the excavation. This fact should be taken into account in their design.

scholarly journals Influence of Weak Interlayer on the Mechanical Performance of the Bolted Rock Mass with a Single Free Surface in Deep Mining

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 496
Author(s):  
Shuxue Ding ◽  
Yuan Gao ◽  
Hongwen Jing ◽  
Xinshuai Shi ◽  
Yanjun Qi ◽  
...  
Keyword(s):  
Free Surface ◽  
Rock Mass ◽  
Mechanical Performance ◽  
Test System ◽  
Surrounding Rock ◽  
Mining Engineering ◽  
Weak Interlayer ◽  
Dip Angle ◽  
The Stability ◽  
The Impact

The existence of the weak interlayer in the roadway surrounding rock mass presents a huge threat to the stability of the underground structure and the safety of mining engineering. By the characteristics of strong adaptability, superior anchoring effect and high efficiency of construction, rock bolt has been widely applied in mine reinforcement. However, the influence of the weak interlayer on the compressive performance of the bolted rock mass is still poorly understood due to the challenges in constructing an efficient experimental platform and complex testing processes. Here, we used the self-developed test system to investigate the influence of the thickness, uniaxial compressive strength, and dip angle of the weak interlayer on the compressive behavior of the bolted rock mass with a single free surface. The results show that the weak interlayer has a great weakening effect on the peak strength and elastic modulus of the specimens due to its low mechanical properties, as well as influencing the crack distribution and failure mode of the samples. As the strength of the weak interlayer is lower than 1.27 MPa, the thickness exceeds 20 mm, and the dip angle exceeds 15°, the synergistic bearing effect will be significantly reduced and affect the mechanical performance of the specimens. The evolution of the bolt force and bending moment are greatly impacted by the deformation process which could be divided into distinct stages of destruction, thereby providing an excellent detection method for judging the stability of the surrounding rock of the mine. The discovery of this research promote a better understanding of the impact of the weak interlayer on mining engineering and guide the mine reinforcement in the future.

Study on the Rock Slope Landslide Caused by Earth Penetrating Weapon Explosion

2013 ◽  
Vol 376 ◽  
pp. 108-112
Author(s):  
Jie Zhong Hao ◽  
Cun Cheng Shi ◽  
Jie Li ◽  
Yun Hou Sun
Keyword(s):  
Rock Mass ◽  
Rock Slope ◽  
Limit Equilibrium ◽  
Seismic Attenuation ◽  
Inertia Force ◽  
Loading Method ◽  
The Earth ◽  
The Stability ◽  
Mass Volume ◽  
The Impact

The rigid limit equilibrium method can be used to analyse the slope stability under the earth penetrating weapon explosion. The explosion seismic inertia force is equivalent by the equivalent static loading method and seismic attenuation is also taken into account, and then the calculating formula is got. The calculation of the example indicates that the stability coefficient increases as the potential sliding rock mass volume increasing and the critical sliding point is corresponding to the maximum sliding rock mass volume. The impact point and explosion center depth influence the slope sliding.

Underground seasonal storage of gas: testing numerical modelling tools with application to i) a deep aquifer-layer, and ii) salt caverns.

2020 ◽  
Author(s):  
Francesca Silverii ◽  
Djamil Al-Halbouni ◽  
Magdalena Stefanova Vassileva ◽  
Gudrun Richter ◽  
Rongjiang Wang ◽  
...  
Keyword(s):  
Stress State ◽  
Pore Pressure ◽  
Gas Storage ◽  
Physical Parameters ◽  
Elastic Model ◽  
Salt Cavern ◽  
The Stability ◽  
Salt Caverns ◽  
Storage Facilities

<p>Within the framework of the SECURE project, we test modeling techniques used for natural geothermal and volcanic reservoirs and apply them to anthropic underground gas storage facilities. These systems indeed share similar mechanics and physical properties, however gas reservoirs are often extensively monitored, and better imaged. In order to manage fluctuations between gas supply and demand, natural gas can be temporarily stored in different underground storage facilities, such as depleted gas/oil fields, natural aquifers, and salt cavern formations. When properly monitored during storage and withdrawal (production) of gas, these systems provide a unique opportunity to investigate how reservoirs evolve at different time scales, modify the surrounding stress state, produce deformation coupled with diffusion processes, and possibly induce/trigger earthquakes on nearby faults.</p><p>In the first case study we addressed within the framework of SECURE project, we take advantage of well constrained reservoir geometry and physical parameters, records of gas injection/production rates, pore pressure variations, and a local seismic catalog at a gas reservoir in Spain. We implement a poro-elastic model to simulate pressure temporal variations, estimate related stress-state variations, and study eventual relationship with small recorded seismic events. The model is based the software POEL by Wang et al., (2003), a semi-analytical physics-based numerical scheme which allows the computation of transient and steady-state solutions in response to pore-pressure variations. Being 2D axisymmetric, POEL drastically simplify the geometry of the reservoir, but it is particularly suitable to link observables such as pressure variations within the reservoir with the physical/mechanical processes occurring in the surroundings.</p><p>In the second case study we address the stability condition for salt caverns which has been excavated for salt mining purposes. We make use of 2D discrete-element geomechanical models to compare numerical simulation results with field observations in terms of surface subsidence. With this numerical model we consider different pressure conditions for the fluid (brine) filling the cavity, and return different scenarios for the stability of a salt cavern. Such modeling effort aims at improving our understanding of middle-to-long term stability conditions, for those cavities that have been dismissed after anthropic operations such as salt extraction, but also seasonal gas storage.</p>

Dietary Vitamin and Stability of Oral Anticoagulation: Proposal of a Diet with Constant Vitamin K1 Content

1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Vitamin K ◽  
High Performance ◽  
Case Reports ◽  
Food Composition ◽  
Dietary Guidelines ◽  
Dietary Vitamin ◽  
Vitamin K1 ◽  
The Stability ◽  
The Impact

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.

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