Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equi...Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.展开更多
This article introduces the current situation of the smart then describes the relationship of meter reliability characteristics meter＇s reliability and the failure mechanisms at first, and combined with its Bathtub C...This article introduces the current situation of the smart then describes the relationship of meter reliability characteristics meter＇s reliability and the failure mechanisms at first, and combined with its Bathtub Curve. It also introduces both the feasible failure tree model for meter lifecycle prediction based on actual experiences and meter reliability prediction methodology by SN 29500 norms based on this model. This article also brings forward that it is necessary that the ＂Learning Factor＂ shall be adopted in meter reliability prediction for new materials, new process, and customized parts by referring to GJB/Z299C. Thereafter, this article also tries to apply IEC 62059 and JB/T 50070 to introduce the feasible method for the lifecycle prediction result verification by accelerated lifecycle test. Furthermore, the article also explores ways to increase the firmware reliability in smart meter.展开更多
HIPS （High Integrity Protection System） is a really important system to protect the fractionation column from overpressure and to protect any atmospheric pollution from flare stack, scrubber and VCU （vapor combusti...HIPS （High Integrity Protection System） is a really important system to protect the fractionation column from overpressure and to protect any atmospheric pollution from flare stack, scrubber and VCU （vapor combustion unit）, etc. KOSHA （Korea Occupational Safety ＆ Health Agency） made criteria about HIPS inspection in 2007 to enforce HIPS inspection. HIPS is the first system which KOSHA and KGS （Korea Gas Safety Corp.） officially required to attach SIL verification report in the Process Safety Report. KOSHA and KGS uniformly require SIL3 for HIPS and require to configure the safety instrumented function to meet SIL3 requirement. The flare system with SIL3 application should have the interlocks to shut off the heat source in case of high pressure from tower, the cooling system failure and the power failure. KOSHA and KGS admit that the flare load is 0 where SIL 3 is applied to the flare system. So it is beneficial to plant because the equipment investment cost can be saved if SIL3 is applied to the flare system. By this reason, so many plants in Korea applied SIL3 to the flare system, scrubber system and VCU, etc. For SIL3 application, the redundant shutdown valve with PST （partial stroke test） should be installed with 1 out of 2 voting and the positioner for PST function should have HART communication function. There were problems caused by HART communication devices, so the system design should be cautiously done considering the operation availability and safety at the same time.展开更多
基金Projects(1004025,51174044,50934006)supported by the National Natural Science FoundationProject(2011AA060400)supported by the National High Technique Research and Development Program of ChinaProject(Sklgduek1113)supported by Funds of the State Key Laboratory for Geomechanics&Deep Underground Engineering,Chinese University of Mining and Technology,China
文摘Based on the height of back-filled materials, thickness of ore body, height of boundary pillar and dipping angle of ore body and water pressure, the safety factors of all the pillars are calculated with the limit equilibrium method. The calculation results present that the safety factors of pillars in Sections 19, 20, 24, 28 are less than 1.3, and those of unstable sections are identified preliminarily. Further, a numerical investigation in Sections 18, 20, 22, 24, 25 and 28 implemented with numerical code RFPA20 is employed to further validate the pillar performance and the stability of stopes. The numerical results show the pillars in Sections 18, 22 and 24 are stable and the designed pillar size is suitable. The width of the ore body near Section 28 averages 20 m, failure occurs in the left stope, but the boundary pillars near Section 28 maintain good performance. The pillars in Sections 20 and 25 are unstable which are mainly affected by the Faults F8 and F18. The existence of faults alters the stress distribution, failure mode and water inrush pathway. This work provides a meaningful standard for boundary pillar and stope design in a mine as it transitions from an open pit to underground.
文摘This article introduces the current situation of the smart then describes the relationship of meter reliability characteristics meter＇s reliability and the failure mechanisms at first, and combined with its Bathtub Curve. It also introduces both the feasible failure tree model for meter lifecycle prediction based on actual experiences and meter reliability prediction methodology by SN 29500 norms based on this model. This article also brings forward that it is necessary that the ＂Learning Factor＂ shall be adopted in meter reliability prediction for new materials, new process, and customized parts by referring to GJB/Z299C. Thereafter, this article also tries to apply IEC 62059 and JB/T 50070 to introduce the feasible method for the lifecycle prediction result verification by accelerated lifecycle test. Furthermore, the article also explores ways to increase the firmware reliability in smart meter.
文摘HIPS （High Integrity Protection System） is a really important system to protect the fractionation column from overpressure and to protect any atmospheric pollution from flare stack, scrubber and VCU （vapor combustion unit）, etc. KOSHA （Korea Occupational Safety ＆ Health Agency） made criteria about HIPS inspection in 2007 to enforce HIPS inspection. HIPS is the first system which KOSHA and KGS （Korea Gas Safety Corp.） officially required to attach SIL verification report in the Process Safety Report. KOSHA and KGS uniformly require SIL3 for HIPS and require to configure the safety instrumented function to meet SIL3 requirement. The flare system with SIL3 application should have the interlocks to shut off the heat source in case of high pressure from tower, the cooling system failure and the power failure. KOSHA and KGS admit that the flare load is 0 where SIL 3 is applied to the flare system. So it is beneficial to plant because the equipment investment cost can be saved if SIL3 is applied to the flare system. By this reason, so many plants in Korea applied SIL3 to the flare system, scrubber system and VCU, etc. For SIL3 application, the redundant shutdown valve with PST （partial stroke test） should be installed with 1 out of 2 voting and the positioner for PST function should have HART communication function. There were problems caused by HART communication devices, so the system design should be cautiously done considering the operation availability and safety at the same time.
