Analysis of the Stress Distribution in Inclined Backfilled Stopes Using Closed-form Solutions and Numerical Simulations

Backfilling is often used in underground mines to ensure stope stability and workers safety. Evaluating the stress state in the fill material and surrounding rock mass is a critical step for the design of backfilled stopes. The majority of analytical (closed-form) solutions to obtain the stresses have been developed for vertical openings. In reality, most mine stopes have inclined walls. Previous studies have shown that in such cases, the stresses developing along the hanging wall and footwall can be quite different. Recent investigations have also indicated that the stress transfer between the relatively soft backfill and stiff rock mass is typically not as well developed in inclined stopes, compared with vertical openings. In this paper, the authors first recall analytical solutions that have been proposed for evaluating the stresses in backfilled stopes with vertical and inclined walls. Numerical simulations are then used to assess the interactions between the backfill and rock mass. The influence of backfill properties and stope geometry (in terms of height, width and inclination) is examined. The stresses obtained from existing solutions and new simulations are then compared and discussed. This comparison points to significant differences, indicating that an alternate formulation is required to properly assess the stress state in inclined stopes.

[2]  Tikou Belem,et al.  Design and Application of Underground Mine Paste Backfill Technology , 2008 .

[3]  Sven Knutsson.  Stresses in the hydraulic backfill from analytical calculations and in-situ measurements , 1981 .

[4]  W. A. Hustrulid,et al.  Underground mining methods : engineering fundamentals and international case studies , 2001 .

[5]  Li Li,et al.  Modeling arching effets in narrow backfilled stopes with FLAC , 2003 .

[6]  Michel Aubertin,et al.  Integrated mine tailings management by combining environmental desulphurization and cemented paste backfill: Application to mine Doyon, Quebec, Canada , 2008 .

[7]  Michel Aubertin,et al.  Numerical investigation of the geomechanical response of adjacent backfilled stopes , 2015 .

[8]  Sankha Widisinghe,et al.  Vertical Stress Determination within Backfilled Mine Stopes , 2014 .

[9]  Michel Aubertin,et al.  A Three-Dimensional Analysis of the Total and Effective Stresses in Submerged Backfilled Stopes , 2009 .

[10]  Nagaratnam Sivakugan,et al.  Arching within hydraulic fill stopes , 2007 .

[11]  Nagaratnam Sivakugan,et al.  Analytical Expression for Vertical Stress within an Inclined Mine Stope with Non-parallel Walls , 2014, Geotechnical and Geological Engineering.

[12]  Kandiah Pirapakaran.  Load-deformation characteristics of minefills with particular reference to arching and stress developments , 2008 .

[13]  A. Fourie,et al.  Handbook on Mine FIll , 2005 .

[14]  Chia-Nan Liu,et al.  Finite Element Analysis of Earth Pressures for Narrow Retaining Walls , 2007 .

[15]  Caceres Doerner,et al.  Effect of delayed backfill on open stope mining methods , 2005 .

[16]  LiLi,et al.  Effect of drainage and sequential filling on the behavior of backfill in mine stopes , 2014 .

[17]  Nagaratnam Sivakugan,et al.  Arching in Soils Applied to Inclined Mine Stopes , 2011 .

[18]  Michel Aubertin,et al.  Three-dimensional stress state in inclined backfilled stopes obtained from numerical simulations and new closed-form solution , 2018 .

[19]  Li Li,et al.  Formulation of a three dimensional analytical solution to evaluate stresses in backfilled vertical narrow openings , 2005 .

[20]  A Marston,et al.  THE THEORY OF EXTERNAL LOADS ON CLOSED CONDUITS IN THE LIGHT OF THE LATEST EXPERIMENTS , 1930 .

[21]  M. Aubertin,et al.  Erratum to: Evaluation of the Stress State in Two Adjacent Backfilled Stopes Within an Elasto-Plastic Rock Mass , 2015 .

[22]  Michel Aubertin,et al.  An analytical solution for the nonlinear distribution of effective and total stresses in vertical backfilled stopes , 2010 .

[23]  Nawfal El Mkadmi.  Simulations du comportement géotechnique des remblais dans les chantiers miniers: effets du drainage et de la consolidation , 2012 .

[24]  David F. McCarthy,et al.  Essentials of Soil Mechanics and Foundations: Basic Geotechnics , 1982 .

[25]  N. Falaknaz.  Analysis of the Geomechanical Behavior of Two Adjacent Backfilled Stopes Based on Two and Three Dimensional Numerical Simulations , 2014 .

[26]  Michel Aubertin,et al.  An improved analytical solution to estimate the stress state in subvertical backfilled stopes , 2008 .

[27]  Li Li,et al.  Interaction Between Backfill and Rock Mass in Narrow Stopes Interacción Entre el Relleno y la Masa de Roca en Excavaciones Escalonadas Estrechas , 2003 .

[28]  Mw Grabinsky.  In situ monitoring for ground truthing paste backfill designs , 2010 .

[29]  Michel Aubertin,et al.  Numerical investigation of earth pressure coefficient along central line of backfilled stopes , 2017 .

[30]  Mw Grabinsky,et al.  In situ measurements of cemented paste backfill at the Cayeli Mine , 2012 .

[31]  J. M. Duncan,et al.  Soil Modulus Correlations , 2013 .

[33]  Pengyu Yang.  Investigation of the Geomechanical Behavior of Mine Backfill and its Interaction with Rock Walls and Barricades , 2016 .

[34]  Nagaratnam Sivakugan,et al.  Arching in Inclined and Vertical Mine Stopes , 2011 .

[35]  Michel Aubertin,et al.  A New Analytical Solution for the Stress State in Inclined Backfilled Mine Stopes , 2017, Geotechnical and Geological Engineering.

[36]  R. L. Handy,et al.  Geotechnical engineering: Soil and foundation principles and practice, fifth edition / R. L. Handy, M.G. Spangler , 2007 .

[37]  D Liston,et al.  Utilisation of cemented rockfill, cemented hydraulic fill and paste to successfully achieve ore production expansion to 2 Mtpa at Chelopech Mine , 2014 .

[38]  Michel Aubertin,et al.  Numerical Investigation of the Stress State in Inclined Backfilled Stopes , 2009 .

[39]  A. J. Valsangkar,et al.  Earth pressures on unyielding retaining walls of narrow backfill width , 2001 .

[40]  Nagaratnam Sivakugan,et al.  Can Soil Arching Be Insensitive to ϕ , 2010 .