In underground mining,there has been an increasing use of"cemented paste"for the backfilling of stopes.As this cemented paste backfill(CPB)enters the stope as a fluid,shotcrete barricades are often used to r...In underground mining,there has been an increasing use of"cemented paste"for the backfilling of stopes.As this cemented paste backfill(CPB)enters the stope as a fluid,shotcrete barricades are often used to retain the fill material during and after the filling operations.However,failures of barricades have been reported around the world in recent years.This paper presents an analytical solution based on the elastic thin plate theory for calibrating the design of shotcrete barricades in underground mines using CPB.This solution was used to determine the quantitative relationships between the lateral loading from the paste and the barricade response during the backfilling process.The results show that the proposed solution agrees well with in situ data.According to the actual barricade responses,the acceptable tensile stress and an analysis method of cracks development are proposed.The proposed solution has practical significance for underground mines.展开更多
Voids(referred to as "stopes") are generally created during underground mining activities and can lead to both local and regional geotechnical instabilities. To assist in managing the stability of mining-rel...Voids(referred to as "stopes") are generally created during underground mining activities and can lead to both local and regional geotechnical instabilities. To assist in managing the stability of mining-related voids and improving the recovery of orebodies, tailing-based backfill technology has been widely used around the world. In the design of tailing-based backfill strategy, the specific function and engineering requirements of the filling are intimately dependent on the stress distribution within the backfilled stope. In this paper, the main mechanics involved in tailing-based backfill in underground mines, which include arching, consolidation, hydration process, and movement of surrounding rocks, are reviewed. Research on the safety of a barricade and stability of an exposed fill face are also presented. In conclusion, the backfilling process should be performed on the basis of a better understanding of the complicated interactions of the mechanisms of filling, consolidation, and hydration process(when cement is added).展开更多
An attempt is made to locate nuclear technology within a logical context considering history, risks, societal catastrophes and perspectives: the need is identified for a new direction in the exploitation in order to r...An attempt is made to locate nuclear technology within a logical context considering history, risks, societal catastrophes and perspectives: the need is identified for a new direction in the exploitation in order to restore the role in energy production. We depict the situation coming from a marvelous history of discoveries started at the beginning of the XX century;heroes are recalled who made possible something that is inconceivable today: design, construction and production of electricity in a few years;that history was tainted by intentional nuclear explosions, </span><i><span style="font-size:12px;font-family:Verdana;">i.e.</span></i><span style="font-size:12px;font-family:Verdana;"> the original sin that we are now paying. Then, we attempt to show that the societal risk is an inherent part of the civilization. Restoring the public trust (towards nuclear fission technology) by matching nuclear safety with the current technological status and advancers in risk assessment is the key objective. The </span></span><span style="font-family:Verdana;font-size:12px;">“</span><span style="font-family:Verdana;font-size:12px;">independent assessment</span><span style="font-family:Verdana;font-size:12px;">”</span><span style="font-family:Verdana;font-size:12px;">, or a principle for the exploitation of nuclear energy already stated in the 50’s of the previous century, shall then re-appear. This is used to erect the signpost for a </span><span style="font-family:Verdana;font-size:12px;">“</span><span style="font-family:Verdana;font-size:12px;">dynamic barricade</span><span style="font-family:Verdana;font-size:12px;">”</span><span style="font-family:Verdana;font-size:12px;"> to further reduce the risk of operation of nuclear reactors and to match the design with current technological capabilities and with the frontiers of the research.展开更多
基金financially supported by the China Scholarship Council(No.201506420049)。
文摘In underground mining,there has been an increasing use of"cemented paste"for the backfilling of stopes.As this cemented paste backfill(CPB)enters the stope as a fluid,shotcrete barricades are often used to retain the fill material during and after the filling operations.However,failures of barricades have been reported around the world in recent years.This paper presents an analytical solution based on the elastic thin plate theory for calibrating the design of shotcrete barricades in underground mines using CPB.This solution was used to determine the quantitative relationships between the lateral loading from the paste and the barricade response during the backfilling process.The results show that the proposed solution agrees well with in situ data.According to the actual barricade responses,the acceptable tensile stress and an analysis method of cracks development are proposed.The proposed solution has practical significance for underground mines.
基金The first author was financially supported by the China Scholarship Council(No.201506420049).
文摘Voids(referred to as "stopes") are generally created during underground mining activities and can lead to both local and regional geotechnical instabilities. To assist in managing the stability of mining-related voids and improving the recovery of orebodies, tailing-based backfill technology has been widely used around the world. In the design of tailing-based backfill strategy, the specific function and engineering requirements of the filling are intimately dependent on the stress distribution within the backfilled stope. In this paper, the main mechanics involved in tailing-based backfill in underground mines, which include arching, consolidation, hydration process, and movement of surrounding rocks, are reviewed. Research on the safety of a barricade and stability of an exposed fill face are also presented. In conclusion, the backfilling process should be performed on the basis of a better understanding of the complicated interactions of the mechanisms of filling, consolidation, and hydration process(when cement is added).
文摘An attempt is made to locate nuclear technology within a logical context considering history, risks, societal catastrophes and perspectives: the need is identified for a new direction in the exploitation in order to restore the role in energy production. We depict the situation coming from a marvelous history of discoveries started at the beginning of the XX century;heroes are recalled who made possible something that is inconceivable today: design, construction and production of electricity in a few years;that history was tainted by intentional nuclear explosions, </span><i><span style="font-size:12px;font-family:Verdana;">i.e.</span></i><span style="font-size:12px;font-family:Verdana;"> the original sin that we are now paying. Then, we attempt to show that the societal risk is an inherent part of the civilization. Restoring the public trust (towards nuclear fission technology) by matching nuclear safety with the current technological status and advancers in risk assessment is the key objective. The </span></span><span style="font-family:Verdana;font-size:12px;">“</span><span style="font-family:Verdana;font-size:12px;">independent assessment</span><span style="font-family:Verdana;font-size:12px;">”</span><span style="font-family:Verdana;font-size:12px;">, or a principle for the exploitation of nuclear energy already stated in the 50’s of the previous century, shall then re-appear. This is used to erect the signpost for a </span><span style="font-family:Verdana;font-size:12px;">“</span><span style="font-family:Verdana;font-size:12px;">dynamic barricade</span><span style="font-family:Verdana;font-size:12px;">”</span><span style="font-family:Verdana;font-size:12px;"> to further reduce the risk of operation of nuclear reactors and to match the design with current technological capabilities and with the frontiers of the research.