Evaluation of the seismic rock mass response to mining and the impact of preconditioning using an epidemic-type aftershock model

2022 ◽  
Vol 150 ◽  
pp. 104975
Author(s):  
F.J. Gonzalez ◽  
J.A. Vallejos ◽  
E. Rojas ◽  
P. Landeros
Keyword(s):  
Rock Mass ◽  
The Impact

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

Study on Deformation and Damage of Rock Mass Subject to High In Situ Stress by Using a Elastoplastic Damage Model and Considering the Impact of Weak Planes

2013 ◽  
Vol 838-841 ◽  
pp. 705-709
Author(s):  
Yun Hao Yang ◽  
Ren Kun Wang
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Damage Model ◽  
Back Analysis ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
High In Situ Stress ◽  
Underground Caverns ◽  
The Impact

Large scale underground caverns are under construction in high in-situ stress field at Houziyan hydropower station. To investigate deformation and damage of surrounding rock mass, a elastoplastic orthotropic damage model capable of describing induced orthotropic damage and post-peak behavior of hard rock is used, together with a effective approach accounting for the presence of weak planes. Then a displacement based back analysis was conducted by using the measured deformation data from extensometers. The computed displacements are in good agreement with the measured ones at most of measurement points, which confirm the validities of constitutive model and numerical simulation model. The result of simulation shows that damage of surrounding rock mass is mainly dominated by the high in-situ stress rather than the weak planes and heavy damage occur at the cavern shoulders and side walls.

The impact of structural-tectonic of the rock mass on the formation and development of geo-deformation processes

2011 ◽  
pp. 2047-2051
Author(s):  
E Freiberg ◽  
E Bellendir ◽  
V Golitsyn ◽  
N Ablyamitov ◽  
E Cherkez ◽  
...  
Keyword(s):  
Rock Mass ◽  
Deformation Processes ◽  
The Impact

scholarly journals Stability Assessment of Mining Excavations: the Impact of Large Depths

2018 ◽  
Vol 40 (3) ◽  
pp. 180-187
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Łukasz Bednarek
Keyword(s):  
Rock Mass ◽  
In Situ Monitoring ◽  
Stability Assessment ◽  
Underground Excavations ◽  
Deformation Prediction ◽  
Large Depth ◽  
Coal Deposits ◽  
The Impact

AbstractBack in the early 1980s, coal deposits occurring at depths of ~700 m below surface were already regarded as large-depth deposits. Meanwhile, today the borderline depth of large-depth mining has extended to >1,000 m. Design, excavation and maintenance of mining roadways at the depth of >1,000 m have, therefore, become crucial issues in a practical perspective in recent years. Hence, it is now extremely important to intensify research studies on the influence of large depths on the behaviour of rock mass and deformation of support in underground excavations. The paper presents the results of the study carried out in five mining excavations at depths ranging from 950 to 1,290 m, where monitoring stations with measurement equipment were built. The analysis of data from laboratory and coal mine tests, as well as in situ monitoring, helped to formulate a set of criteria for stability assessment of underground excavations situated at large depths. The proposed methodology of load and deformation prediction in support systems of the excavations unaffected by exploitation is based on the criteria referring to the depth of excavation and the quality of rock mass. The depth parameter is determined by checking whether the analysed excavation lies below the critical depth, whereas the rock mass quality is determined on the basis of the roof lithology index (WL) and the crack intensity factor (n)

Numerical Study on Influence of Joint Characters on Rock Mechanical Parameters

2011 ◽  
Vol 201-203 ◽  
pp. 2909-2912
Author(s):  
Yan Feng Feng ◽  
Tian Hong Yang ◽  
Hua Wei ◽  
Hua Guo Gao ◽  
Jiu Hong Wei
Keyword(s):  
Rock Mass ◽  
Compression Strength ◽  
Numerical Study ◽  
Process Analysis ◽  
Failure Process ◽  
Deformation Modulus ◽  
Rock Joints ◽  
Structured Surfaces ◽  
Trace Length ◽  
The Impact

Rock mass is the syntheses composed of kinds of structure and structured surfaces. The joint characters is influencing and controlling the rock mass strength, deformation characteristics and rock mass engineering instability failure in a great degree. Through using the RFPA2D software, which is a kind of material failure process analysis numerical methods based on finite element stress analysis and statistical damage theory, the uniaxial compression tests on numerical model are carried, the impact of the trace length of rock joints and the fault throws on rock mechanics parameters are studied. The results showed that with the gradual increase of trace length,compression strength decreased gradually and its rate of variation getting smaller and smaller, the deformation modulus decreased but the rate of variation larger and larger; with the fault throws increasing, the compression strength first increases and then decreases, when the fault throw is equal to the trace length, the deformation modulus is the largest. When the joint trace length is less than the fault throw, the rate of the deformation modulus is greater than that of trace length, but the deformation modulus was not of regular change.

Rock Movement in Tectonic Zones. Mining Activities and Rock Pressure Management in the Norilsk-Kharaelakh Fault Area

2020 ◽  
pp. 148-151
Author(s):  
S.G. Kirillov ◽  
Z.G. Ufatova ◽  
I.F. Khrushchev ◽  
K.A. Bashirov
Keyword(s):  
Rock Mass ◽  
High Mobility ◽  
Mining Operations ◽  
Profile Line ◽  
Initial Stage ◽  
Tectonic Zones ◽  
Rock Movement ◽  
Hazard Level ◽  
And Control ◽  
The Impact

The article describes the rock mass state within the boundaries of the Skalistiy mining allotment. The ore mass within the mine field was found to preserve its rock-bump hazard and show high mobility in the impact zone of the Norilsk-Kharaelakh Fault and the associated high failure potential manifested as roof cavings. Based on the monitoring results along underground profile lines, it was concluded that the displacement process is currently at its initial stage. Moreover, the maximum subsidence in the central part of the profile line is about 3 times higher (up to 35 mm) than in other areas. This is caused by immediate proximity of this zone to the Norilsk-Kharaelakh Fault. Assessment of the bump hazard level of this rock mass with the help of the Prognoz-2 instrument that was performed by the rock-bump forecasting and control teams of the mine and the Norilskshakhtstroy company, showed the 'Not Hazardous' category in all cases. However, the progress of mining operations towards the Norilsk-Kharaelakh Fault may lead to deterioration in the condition of mine workings. This can be manifested through rock exfoliation from the walls of the advance workings of the safety layer in highly and extremely faulted rocks. In addition, permanent workings, which are one of the most critical structures of the production level and which will be used until the development of the deposit area adjacent to the Norilsk-Kharaelakh Fault is completed, will be maintained in increasingly difficult conditions. The article describes recommendations for mining operations in the fault area with account for the current mining and geomechanical situation and the potential for its change.

scholarly journals The assessment of lining structure impact on radon behaviour inside selected underground workings under the cour d’honneur of Książ castle

2020 ◽  
Vol 326 (2) ◽  
pp. 1199-1211
Author(s):  
Lidia Fijałkowska-Lichwa
Keyword(s):  
Rock Mass ◽  
Reinforced Concrete ◽  
Radon Concentration ◽  
Activity Concentration ◽  
Concrete Lining ◽  
Air Movement ◽  
Lining Structure ◽  
Underground Workings ◽  
The Mean ◽  
The Impact

Abstract The results based on 2-year long measurements 01 Jan. 2016–2031 Dec. 2017 have been used for discussing the influence of tunnel lining on the size of 222Rn activity concentration and the impact of the employed rock mass insulation on natural convective air exchange. In April, air movement started when the temperature was at least 7 °C lower than the mean inside. Between May and October, an increase to 9 °C above the underground temperature resulted in an increase of radon concentration. An unconstrained convection process did not start until November and it continued until the end of March. The reinforced concrete lining insulated the fractured and absorptive rock mass. The roof and the sidewall lining had little impact on air movement process.

scholarly journals Analysis of load of a powered roof support’s hydraulic leg

2018 ◽  
Vol 71 ◽  
pp. 00002 ◽  
Author(s):  
Dawid Szurgacz ◽  
Jarosław Brodny
Keyword(s):  
Rock Mass ◽  
Hydraulic System ◽  
Impact Load ◽  
Load Condition ◽  
Dynamic Impact ◽  
Registration System ◽  
Free Falling ◽  
The Impact ◽  
Impact Mass ◽  
Roof Support

The main purpose of the powered roof support is to protect headings from the impact of the rock mass. The result of such impact is static and dynamic load impacting the support section, which is carried by its construction. The basic elements of the construction of the support are hydraulic legs, whose task is to ensure adequate strength of its setting. Particularly in the case of dynamic impact of the rock mass, these legs are exposed to a very unfavourable load condition. Therefore, it is necessary to conduct tests to determine the parameters of operation for this type of loads. The paper presents the results of tests on the hydraulic leg subjected to impact load with free falling impact mass. The purpose of the research was to determine the parameters of the leg's operation, i.e. the time periods of pressure in the space under the piston and other elements of the hydraulic system. The tests were conducted in compliance with designed methodology and included innovative registration system. The obtained results clearly indicate the correctness of the adopted assumptions. According to the authors, the results should be applied during selection and operation of a powered roof support.

Failure Mode Analysis of Bedding Rock Slope Affected by Rock Mass Structural Plane

2014 ◽  
Vol 602-605 ◽  
pp. 594-597 ◽  
Author(s):  
En An Chi ◽  
Tie Jun Tao ◽  
Ming Sheng Zhao ◽  
Qiang Kang
Keyword(s):  
Rock Mass ◽  
Slope Failure ◽  
Failure Modes ◽  
Shear Stiffness ◽  
Mode Analysis ◽  
Structural Plane ◽  
Plane Failure ◽  
Failure Mode Analysis ◽  
Dip Angle ◽  
The Impact

Based on the discrete element numerical simulation, the change of failure modes of slope influenced by parameters of rock mass structural plane is studied. It is shown the failure modes shift gradually from the bedding sliding failure modes to the sliding-bending failure modes with the increase of the strength of the rock mass structural plane; The slope failure modes are mainly sliding failure modes with the increasing of the normal and shear stiffness and spacing of rock structural plane. Failure modes shift from shearing slip failure modes to shearing slip and buckling failure modes and finally to the tilting failure modes with the increase of the rock structural plane dip angle. The impact of the rock structural plane cohesion to the slope stability is the greatest, and the stiffness is the least.

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.

Sign in / Sign up

Export Citation Format

Share Document