Rock Stress Around Noncircular Tunnel: a New Simple Mathematical Method

Shen, Wenlong; Wang, Xiangyu; Bai, Jianbiao; Li, Wenfeng; Yu, Yang

doi:10.4208/aamm.2016.m1530

Cited by 13 publications

(13 citation statements)

References 18 publications

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“…The applicability of the criterion to other roadways, whose instability is mainly attributed to the retreat of longwall panels, needs further investigation. This is because longwall-affected roadways may experience different failure mechanism, [43][44][45][46][47] comparing to the roadway failure caused by high in situ stress condition.…”

Section: Discussionmentioning

confidence: 99%

Depressurizing boreholes for mitigating large deformation of the main entry

Wang

Zheng

Shen

et al. 2019

Energy Science & Engineering

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The main entries in longwall coal mine frequently encounter large deformation, depending on the stress environment. Depressurizing boreholes are applicable to reduce the large deformation; however, it is difficult to determine the proper parameters (diameter and spacing) for an effective implementation. This study aims to propose feasible design criteria for the quantification of those parameters. We first developed a rigorous numerical model, for a roadway in Zhangshuanglou coal mine, using the rock mechanical properties determined from extensive laboratory measurements and analyses. We then investigated the dependency of the stress transfer and roadway deformation on the ratio of borehole diameter and spacing (D/R and D/I). The symbols of D, R, and I represented the diameter, row spacing, and interspacing of the boreholes, respectively. We found that (a) D/R has to be between 1:6 and 1:2; and (b) D/I has to be between 1:6 and 1:4, for sufficient depressurization in the surrounding rocks. The optimized borehole diameter and spacing parameters were applied in the field where the deformation of roadway was significantly reduced. Finally, we proposed a criterion to determine those parameters of depressurization boreholes for application in other geological and mining conditions.

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Section: Discussionmentioning

confidence: 99%

Depressurizing boreholes for mitigating large deformation of the main entry

Wang

Zheng

Shen

et al. 2019

Energy Science & Engineering

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“…In 2017, Shen et al [16] investigated a new simple mathematical method to predict rock stress around a noncircular tunnel, and the method is calibrated and validated with a numerical model. It can be found that the tunnel shapes and polar angles affect the applicable zone of the theoretical model significantly, and the applicable zone of a rectangular tunnel was obtained using this method.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Stresses around Holes Drilled and Filled by Expansive Cement: Case of Isotropic Linear Elastic Block of Rock

Leroy

Chebou

2018

Advances in Materials Science and Engineering

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is work dealt with an essential problem of fragmentation of rocks with expansive cement. e redistribution and magnitude of stresses and displacement generated around holes were done by using Ansys Inc. Code which is based on finite element code. Blocks of rock with one hole, two holes, and nine holes drilled in square mesh and staggered mesh have been considered. Numerical results reveal that many factors can influence the mechanism of fragmentation of a rock by using expansive cement: hole diameter, hole spacing, panel mesh, expansive pressure applied, and the elastic properties of the massif. Stresses and displacements generated globally decrease when spacing holes increase. Normal stresses allow a better stress interaction between holes in the case of square mesh disposition. Staggered mesh disposition generates higher stresses than the square mesh disposition. But the square mesh disposition can be useful for controlled fragmentation in order to obtain block of rock with square geometry. For each expansive cement and rock, there exist suitable range of diameter and spacing hole which can generate high stresses for breaking the rock.

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“…Optimizing the design of such a cylinder requires an understanding of the elastoplastic behavior of the material [4]. Many numerical and analytical works have been done on this subject, especially on uniform rotating discs, to predict the stress field, deformations, and rupture, to avoid the risk of damage when the device is subjected to different loading conditions [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. In 2005, Ahmet N. Eraslan et al [4] obtained in the context of the small deformation theory analytical solutions on flat deformations in elastic tubes operably under pressure grades.…”

Section: Introductionmentioning

confidence: 99%

“…Power-law grading is used for material gradation pattern. In 2017, Wenlong Shen et al [11] investigated a new simple mathematical method to predict rock stress around a noncircular tunnel and the method is calibrated and validated with a numerical model. It can be found that the tunnel shapes and polar angles affect the applicable zone of the theoretical model signiïňĄcantly and the applicable zone of a rectangular tunnel was obtained using this method.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Analytical Calculations for Modeling and Designing Drilling Wicks or Rotary Cutters Based of Functionally Graded Materials

Leroy

Ndop

Nkene

et al. 2018

Journal of Engineering

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Drilling tools or drilling pipes, such as drill bit and mill drill, are often subjected to various forces, including essentially tangential forces, centered on their axis of rotation. The main objective of this work is to find analytical and numerical solutions of the distribution of stress field, deformation, and displacement, when such tools are subjected to such forces. It will be assumed that the instrument in the chosen model in this work is a rotating hollow cylinder constructed from a Functional Graded Material (FGM). Because of the graduation of the FGM, the mechanical and elastic properties such as Young’s modulus, density, and Poisson’s ratio vary in the radial direction according to a power law function. By choosing that the inhomogeneity parameter is between -0.5 and 0.5, we have established the differential equation which describes the equilibrium of the hollow cylinder in rotation under an axial load. The calculations performed have allowed finding an analytical solution which was compared with numerical solutions obtained by using the shooting method and the fourth-order Runge-Kutta algorithm. These analytical and numerical results have shown that the values of tangential stresses are greater than the radial stresses. The radial stresses and tangential and vertical stresses progressively increase with the axial force Fz. The force Fz affects more tangential stresses that the radial stresses. The tangential stress, tangential deformations, and displacements are higher on the inner walls of the cylinder than on the exterior surfaces. The results obtained are very important and can be applied in the modeling and designing wicks and drilling strawberries in order to reduce their rapid wear and damage.

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Rock Stress Around Noncircular Tunnel: a New Simple Mathematical Method

Cited by 13 publications

References 18 publications

Depressurizing boreholes for mitigating large deformation of the main entry

Depressurizing boreholes for mitigating large deformation of the main entry

Numerical Study of Stresses around Holes Drilled and Filled by Expansive Cement: Case of Isotropic Linear Elastic Block of Rock

Numerical and Analytical Calculations for Modeling and Designing Drilling Wicks or Rotary Cutters Based of Functionally Graded Materials

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