Stress Distribution of Wellbore under Non-Uniform In Situ Stress

2014 ◽  
Vol 633-634 ◽  
pp. 1311-1314
Author(s):  
Xiao Zeng Wang ◽  
Zhan Qu ◽  
Yi Hua Dou
Keyword(s):  
Superposition Principle ◽  
Theoretical Method ◽  
Wall Rock ◽  
In Situ Stress ◽  
Shear Stresses ◽  
Failure Mechanics ◽  
Mechanics Model ◽  
The Stability ◽  
The Relationship

The distribution of the non-uniform in situ stress around wellbore will impair the stability of the rock of wellbore wall. Drilling the underbalanced wells and depleted formations, the instability of the wellbore can result in the drilling failure. Mechanics model of the wellbore wall rock is developed. According to the relationship between the stress function and components of stresses, the superposition principle is adopted to develop the formulas of the radial, hoop, and shear stresses of the wellbore wall under the non-uniform in situ stress. The formula of the mud density which do not crash the rock of wellbore wall is derived. The error of the mud density between fitting formula developed in the paper and theoretical method is less than 2.5%. The mud density that ensure the stability of wellbore is determined.

Research on 2D Limit Equilibrium Method of Slopes Considering the Effect of Horizontal In Situ Stress

2013 ◽  
Vol 671-674 ◽  
pp. 245-250
Author(s):  
Wen Hui Tan ◽  
Ya Liang Li ◽  
Cong Cong Li
Keyword(s):  
Limit Equilibrium ◽  
Limit Equilibrium Method ◽  
In Situ Stress ◽  
Open Pit ◽  
Open Pit Mines ◽  
Equilibrium Method ◽  
Iron Mine ◽  
The Stability ◽  
Slice Method

At present, in-situ stress was not considered in Limit Equilibrium Method (LEM) of slopes, the influence of in-situ stress is very small on the stability of conventional slopes, but in deep-depressed open-pit mines, the influence should not be neglected. Formula for calculating the Factor of Safety (FOS) under the effect of horizontal in-situ stress was deduced using General Slice Method (GSM) of two-dimensional (2D) limit equilibrium method in this paper，a corresponding program SSLOPE was built, and the software was used in a deep- depressed open-pit iron mine. The results show that the FOS of the slope decreased by 20% when horizontal in-situ stress is considered, some reinforcements must be taken. Therefore, the influence of in-situ stress on slope stability should be taken into account in deep open –pit mines.

In Situ Stress Measurement and Surrounding Rock Stability Analysis of the Gaoligong Mountain Tunnel

2014 ◽  
Vol 501-504 ◽  
pp. 1766-1773
Author(s):  
Lin Hai Bao
Keyword(s):  
Large Deformation ◽  
Principal Stress ◽  
Stress Measurement ◽  
Pressure Coefficient ◽  
Horizontal Stress ◽  
Wall Rock ◽  
In Situ Stress ◽  
Rock Stability ◽  
Mountain Tunnel

Gaoligong Mountain tunnel is the key project in the Dali-Ruili Railway. In order to optimize the design and guide construction, In-situ stress has been conducted in five boreholes using hydraulic fracturing method, the current shallow crustal in-situ stress state at the project area are obtained according to the measurements results, and deep in-situ stress is predicted using lateral pressure coefficient. The test results show that at depths ranging from 299-979m, the maximum horizontal principal stress is 5.33-30.12Mpa, the minimum horizontal principal stress is 4.94-23.11Mpa, the horizontal principal stress reach 30Mpa at maximum the depth of burial, indicating that the engineering stress filed is dominated by horizontal stress. Based on the In-situ stress data and different distinguish methods, rockburst and large deformation are predicted. The results show that In-situ stress magnitude in this area is classified as high level, and the direction of the maximum horizontal stress is NEE, In-situ stress orientation is conductive to stable of the tunnel. When the tunnel passes through the deep-burial and hard rock, the wall rock may happen rockburst; and the large deformation may happen when the tunnel pass through the weak rock. In order to avoid the disadvantage conditions, reasonable excavation method and safety support method should be adopted during tunnel excavating.

scholarly journals Evaluation of the Influence of In Situ Stress on the Stability of Mine Pit Walls: A Case Study of Songwe Mine

2021 ◽  
Vol 4 (2) ◽  
pp. p1
Author(s):  
Dyson Moses ◽  
Hideki Shimada ◽  
Takashi Sasaoka ◽  
Akihiro Hamanaka ◽  
Tumelo K. M Dintwe ◽  
...  
Keyword(s):  
Active Regions ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Slope Instability ◽  
Open Pit ◽  
Stress Regime ◽  
Tectonically Active ◽  
The Stability ◽  
The Impact

The investigation of the influence of in situ stress in Open Pit Mine (OPM) projects has not been accorded a deserved attention despite being a fundamental concern in the design of underground excavations. Hence, its long-term potential adverse impacts on pit slope performance are overly undermined. Nevertheless, in mines located in tectonically active settings with a potential high horizontal stress regime like the Songwe mine, the impact could be considerable. Thus, Using FLAC3D 5.0 software, based on Finite Difference Method (FDM) code, we assessed the role of stress regimes as a potential triggering factor for slope instability in Songwe mine. The results of the evaluated shearing contours and quantified strain rate and displacement values reveal that high horizontal stress can reduce the stability performance of the pit-wall in spite of the minimal change in Factor of Safety (FoS). Since mining projects have a long life span, it would be recommendable to consider “in situ stress-stability analyses” for OPM operations that would be planned to extend to greater depths and those located in tectonically active regions.

scholarly journals EFFECT OF BLASTING ON THE STABILITY OF LINING DURING EXCAVATION OF NEW TUNNEL NEAR THE EXISTING TUNNEL

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen
Keyword(s):  
Field Data ◽  
Damage Zone ◽  
Field Tests ◽  
Surrounding Rock ◽  
In Situ Test ◽  
The Stability ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.

Study of the Trellis Support of Working Face Roadway in Impact Coal Seam

2014 ◽  
Vol 941-944 ◽  
pp. 2558-2564
Author(s):  
Yu Kai Lv ◽  
Cong Jiang ◽  
Yao Dong Jiang
Keyword(s):  
In Situ Stress ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Working Face ◽  
Coal Bumps ◽  
Roadway Support ◽  
The Stability ◽  
The Impact ◽  
Physical And Mechanical Characteristics

Coal bumps happened many times in mining at No.5 seam of Tangshan coal mine. Strengthen the roadway’s support of working face can effectively reduce disaster losses. With the research background of the 3654 working face, the mine pressure monitoring for the existing support form of roadway has been carried on. Perform a numerical simulation for the original roadway support, base on the in-situ stress and physical and mechanical characteristics of surrounding rock in experimental; study the impact of the stability of roadway’s surrounding rock, while the space change of trellis and change of supporting intensity; optimizing the original support form, so as to maximum reducing the impact of the coal bumps.

Theoretical Study on Coal Mine In Situ Stress’s Monitoring Method

2013 ◽  
Vol 446-447 ◽  
pp. 1113-1117 ◽  
Author(s):  
Hong Biao Wang ◽  
Chao An ◽  
Shan Dong Zhang
Keyword(s):  
Coal Mine ◽  
In Situ Stress ◽  
Mining Engineering ◽  
Stress Monitoring ◽  
Working Process ◽  
Monitoring Method ◽  
Deformation And Failure ◽  
The Stability ◽  
Dynamic Phenomena

For mine mining, In-situ stress is the fundamental force that causes the deformation and failure of surrounding rock in the mining engineering and supporting, and produces mine dynamic phenomena. Among many factors which affecting the stability of mining engineering, In-situ stress is the main and one of the most fundamental factors. According to the In-situ stress monitoring method some coal mine adopted, this paper introduces the concrete principle and working process.

scholarly journals Design of underground structures and analysis of self-support capacity

2018 ◽  
Vol 65 (2) ◽  
pp. 59-70
Author(s):  
Matej Nagy
Keyword(s):  
Rock Mass ◽  
Hard Rock ◽  
In Situ Stress ◽  
Stability Control ◽  
Underground Structures ◽  
Underground Powerhouse ◽  
The Stability ◽  
Methods Numerical

Abstract The complicated rock structures and the stability of surrounding rocks of the underground powerhouse are key ground mechanical challenges for hydropower projects. In this paper, an example of contributing self-support capacity of rock mass to evaluate optimised support for long-term usage of structure is given. It describes importance of investigations in the initial in situ stress distribution, rock mechanical and geological properties, engineering rock mass classifications by different methods, numerical modelling, comparison of tools for stability and support analysis and proper stability control for rock excavation and support. The results show that after underground excavations in hard rock, detailed analysis of measures to investigate deformation and self-supporting capacity creation is useful and a cost-saving procedure.

Sign in / Sign up

Export Citation Format

Share Document