Stability parameters (Monin-Obukhov length L, gradient Richardson number Ri and bulk Rischardson number Ri), which are applicable in urban environment, were discussed for ways of calculating classification standards. ...Stability parameters (Monin-Obukhov length L, gradient Richardson number Ri and bulk Rischardson number Ri), which are applicable in urban environment, were discussed for ways of calculating classification standards. Gradient observations from a 325-m meteorological tower in Beijing are used to categorize Rib based on three different standards of stability proposed by D. Golder, Irwin and Houghton. The results show that it is relatively reasonable for the region of Beijing to apply the classification standard by Irwin.展开更多
Although disintegrated dolomite,widely distributed across the globe,has conventionally been a focus of research in underground engineering,the issue of slope stability issues in disintegrated dolomite strata is gainin...Although disintegrated dolomite,widely distributed across the globe,has conventionally been a focus of research in underground engineering,the issue of slope stability issues in disintegrated dolomite strata is gaining increasing prominence.This is primarily due to their unique properties,including low strength and loose structure.Current methods for evaluating slope stability,such as basic quality(BQ)and slope stability probability classification(SSPC),do not adequately account for the poor integrity and structural fragmentation characteristic of disintegrated dolomite.To address this challenge,an analysis of the applicability of the limit equilibrium method(LEM),BQ,and SSPC methods was conducted on eight disintegrated dolomite slopes located in Baoshan,Southwest China.However,conflicting results were obtained.Therefore,this paper introduces a novel method,SMRDDS,to provide rapid and accurate assessment of disintegrated dolomite slope stability.This method incorporates parameters such as disintegrated grade,joint state,groundwater conditions,and excavation methods.The findings reveal that six slopes exhibit stability,while two are considered partially unstable.Notably,the proposed method demonstrates a closer match with the actual conditions and is more time-efficient compared with the BQ and SSPC methods.However,due to the limited research on disintegrated dolomite slopes,the results of the SMRDDS method tend to be conservative as a safety precaution.In conclusion,the SMRDDS method can quickly evaluate the current situation of disintegrated dolomite slopes in the field.This contributes significantly to disaster risk reduction for disintegrated dolomite slopes.展开更多
In order to scientifically and quantitatively evaluate the stability of the perim-eter rock of the roadway in Baliancheng coal mine,this paper adopts a com prehensive method of field measurement,theoretical analysis,l...In order to scientifically and quantitatively evaluate the stability of the perim-eter rock of the roadway in Baliancheng coal mine,this paper adopts a com prehensive method of field measurement,theoretical analysis,laboratory test and numerical simulation to study the geological and structural characteristics of the perimeter rock of the roadway,the physical and mechanical properties of the perimeter rock as well as the state of the perimeter rock stress,and pro-poses a comprehensive index method for classifying the stability of the perim eter rock of the roadway.The research results show that:the top plate of 18 coal roadway is mainly medium-hard rock composite top plate of siltstone,medium-grained sandstone and coarse sandstone,and the bottom plate is softmediumhard rock composite bottom plate of medium-grained sandstone,fine-grained sandstone and coarse-grained sandstone,the coefficient of coal seam solidity is 1.28,the fissures of perimeter rock are moderately developed,the influence coefficient of mining is 2.71,and the ratio of the maximal hori zontal principal stress to the vertical stress is 1.90,the stability grade of 18 coal roadway perimeter rock belongs to medium stable perimeter rock,after adopt-ing the optimized support scheme,the overall deformation of the roadway is relatively reduced compared with the original support scheme,and the support effect of the roadway perimeter rock is good.展开更多
A dynamic two-zone model is proposed to address the formation of granulation and drying zones in fluidized bed layering granulation processes with internal product classification. The model assumes a constant volume f...A dynamic two-zone model is proposed to address the formation of granulation and drying zones in fluidized bed layering granulation processes with internal product classification. The model assumes a constant volume for the granulation zone, but a variable overall volume for the fluidized bed to account for classified product removal. The model is used to study the effect of various process parameters on dynamics and process stability. Stability is shown to depend on the separation diameter of product removal and the flow rate of the injected liquid. A lower and upper range of separation diameters with stable process behavior are found. In an intermediate range instability in the form of self-sustained oscillations is observed. The lower stability boundary is in qualitative agreement with recent experimental observations （Schmidt, Bück, ＆ Tsotsas, 2015）; the upper boundary was reported in a theoretical paper by Vreman, Van Lare, and Hounslow （2009） based on a single zone model.展开更多
基金Open Foundation by the Guangzhou Institute of Tropical and Marine Meteorology, CMA
文摘Stability parameters (Monin-Obukhov length L, gradient Richardson number Ri and bulk Rischardson number Ri), which are applicable in urban environment, were discussed for ways of calculating classification standards. Gradient observations from a 325-m meteorological tower in Beijing are used to categorize Rib based on three different standards of stability proposed by D. Golder, Irwin and Houghton. The results show that it is relatively reasonable for the region of Beijing to apply the classification standard by Irwin.
基金supported by the National Natural Science Foundation of China(Grant No.42162026)the Applied Basic Research Foundation of Yunnan Province(Grant No.202201AT070083).
文摘Although disintegrated dolomite,widely distributed across the globe,has conventionally been a focus of research in underground engineering,the issue of slope stability issues in disintegrated dolomite strata is gaining increasing prominence.This is primarily due to their unique properties,including low strength and loose structure.Current methods for evaluating slope stability,such as basic quality(BQ)and slope stability probability classification(SSPC),do not adequately account for the poor integrity and structural fragmentation characteristic of disintegrated dolomite.To address this challenge,an analysis of the applicability of the limit equilibrium method(LEM),BQ,and SSPC methods was conducted on eight disintegrated dolomite slopes located in Baoshan,Southwest China.However,conflicting results were obtained.Therefore,this paper introduces a novel method,SMRDDS,to provide rapid and accurate assessment of disintegrated dolomite slope stability.This method incorporates parameters such as disintegrated grade,joint state,groundwater conditions,and excavation methods.The findings reveal that six slopes exhibit stability,while two are considered partially unstable.Notably,the proposed method demonstrates a closer match with the actual conditions and is more time-efficient compared with the BQ and SSPC methods.However,due to the limited research on disintegrated dolomite slopes,the results of the SMRDDS method tend to be conservative as a safety precaution.In conclusion,the SMRDDS method can quickly evaluate the current situation of disintegrated dolomite slopes in the field.This contributes significantly to disaster risk reduction for disintegrated dolomite slopes.
文摘In order to scientifically and quantitatively evaluate the stability of the perim-eter rock of the roadway in Baliancheng coal mine,this paper adopts a com prehensive method of field measurement,theoretical analysis,laboratory test and numerical simulation to study the geological and structural characteristics of the perimeter rock of the roadway,the physical and mechanical properties of the perimeter rock as well as the state of the perimeter rock stress,and pro-poses a comprehensive index method for classifying the stability of the perim eter rock of the roadway.The research results show that:the top plate of 18 coal roadway is mainly medium-hard rock composite top plate of siltstone,medium-grained sandstone and coarse sandstone,and the bottom plate is softmediumhard rock composite bottom plate of medium-grained sandstone,fine-grained sandstone and coarse-grained sandstone,the coefficient of coal seam solidity is 1.28,the fissures of perimeter rock are moderately developed,the influence coefficient of mining is 2.71,and the ratio of the maximal hori zontal principal stress to the vertical stress is 1.90,the stability grade of 18 coal roadway perimeter rock belongs to medium stable perimeter rock,after adopt-ing the optimized support scheme,the overall deformation of the roadway is relatively reduced compared with the original support scheme,and the support effect of the roadway perimeter rock is good.
文摘A dynamic two-zone model is proposed to address the formation of granulation and drying zones in fluidized bed layering granulation processes with internal product classification. The model assumes a constant volume for the granulation zone, but a variable overall volume for the fluidized bed to account for classified product removal. The model is used to study the effect of various process parameters on dynamics and process stability. Stability is shown to depend on the separation diameter of product removal and the flow rate of the injected liquid. A lower and upper range of separation diameters with stable process behavior are found. In an intermediate range instability in the form of self-sustained oscillations is observed. The lower stability boundary is in qualitative agreement with recent experimental observations （Schmidt, Bück, ＆ Tsotsas, 2015）; the upper boundary was reported in a theoretical paper by Vreman, Van Lare, and Hounslow （2009） based on a single zone model.
