A fast explicit finite difference method (FEFDM),derived from the differential equations of one-dimensional steady pipe flow,was presented for calculation of wellhead injection pressure.Recalculation with a traditiona...A fast explicit finite difference method (FEFDM),derived from the differential equations of one-dimensional steady pipe flow,was presented for calculation of wellhead injection pressure.Recalculation with a traditional numerical method of the same equations corroborates well the reliability and rate of FEFDM.Moreover,a flow rate estimate method was developed for the project whose injection rate has not been clearly determined.A wellhead pressure regime determined by this method was successfully applied to the trial injection operations in Shihezi formation of Shenhua CCS Project,which is a good practice verification of FEFDM.At last,this method was used to evaluate the effect of friction and acceleration terms on the flow equation on the wellhead pressure.The result shows that for deep wellbore,the friction term can be omitted when flow rate is low and in a wide range of velocity the acceleration term can always be deleted.It is also shown that with flow rate increasing,the friction term can no longer be neglected.展开更多
The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common...The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.展开更多
With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of...With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.展开更多
目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性...目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性。方法选取2022年1月—2023年1月医院收治的脓毒症肺损伤患者80例,收集患者的一般资料、肺损伤相关指标[动脉血氧合指数(ratio of partial pressure of O_(2) in arterial blood to fraction of inspired oxygen,PaO_(2)/FiO_(2))、肺泡动脉氧分压差(alveolar-arterial oxygen gradient,P(A-a)O_(2))]及SOFA、APACHEⅡ评分情况,根据中医分型标准对脓毒症肺损伤患者进行分型,比较不同分型的脓毒症肺损伤患者以上各观察指标情况并分析相关性。结果脓毒症肺损伤患者以肺热壅痹证型占比最高、35.00%(28/80),其次为瘀血阻肺型27.50%(22/80),肺塞腑实型23.75%(19/80),水饮郁肺型13.75%(11/80)。不同证型的患者在性别、年龄方面差异均无统计学意义(P>0.05);不同证型的患者肺损伤指标PaO_(2)/FiO_(2)、P(A-a)O_(2)差异均有统计学意义(P<0.05);不同证型的患者SOFA、APACHEⅡ评分差异均有统计学意义(P<0.05)。肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺证型与PaO_(2)/FiO_(2)呈显著负相关(P<0.05),与P(A-a)O_(2)、SOFA评分、APACHEⅡ评分呈显著正相关(P<0.05)。结论脓毒症肺损伤患者中医证型主要为肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺,与肺损伤相关指标及SOFA、APACHEⅡ评分密切相关,掌握脓毒症肺损伤辨证分型特点并观察患者肺损伤相关指标及SOFA、APACHEⅡ评分变化,对疾病诊治及预后评估具有较高价值。展开更多
基金Project(Z110803)supported by the State Key Laboratory of Geomechanics and Geotechnical Engineering,ChinaProject(2008AA062303)supported by the National High Technology Research and Development Program of China
文摘A fast explicit finite difference method (FEFDM),derived from the differential equations of one-dimensional steady pipe flow,was presented for calculation of wellhead injection pressure.Recalculation with a traditional numerical method of the same equations corroborates well the reliability and rate of FEFDM.Moreover,a flow rate estimate method was developed for the project whose injection rate has not been clearly determined.A wellhead pressure regime determined by this method was successfully applied to the trial injection operations in Shihezi formation of Shenhua CCS Project,which is a good practice verification of FEFDM.At last,this method was used to evaluate the effect of friction and acceleration terms on the flow equation on the wellhead pressure.The result shows that for deep wellbore,the friction term can be omitted when flow rate is low and in a wide range of velocity the acceleration term can always be deleted.It is also shown that with flow rate increasing,the friction term can no longer be neglected.
基金Projects(50874047,51074014,51174014)supported by the National Natural Science Foundation of China
文摘The stress state around circular openings,such as boreholes,shafts,and tunnels,is usually needed to be evaluated.Solutions for stresses,strains and ultimate bearing capacities of pressurized hollow cylinder are common cases.Stress analytical method for plane problem of a double-layered thick-walled cylinder subjected to a type of non-uniform pressure on the outer surface and uniform radial pressure on the inner surface is given.The power series method of complex function is used.The stress analytical solution is obtained with the assumption that two layers of a cylinder are fully contacted.The distributions of normal and tangential contact stress along the interface,tangential stress on the inner boundary and stresses in the radial direction at θ=0°,45° and 90°,are obtained.An example indicates that,when the elastic modulus of the inner layer of a double-layered thick-walled cylinder is smaller than that of the outer layer,the tangential stress is smaller than that in the corresponding point for a traditional cylinder composed of homogeneous materials.In that way,stress concentration at the inner surface can be alleviated and the stress distribution is more uniform.This is a capable way to enhance the elastic ultimate bearing capacity of thick-walled cylinder.
基金Project(52068004)supported by the National Natural Science Foundation of ChinaProject(2018JJA160134)supported by the Natural Science Foundation of Guangxi Province,ChinaProject(AB19245018)supported by Key Research Projects of Guangxi Province,China。
文摘With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.
文摘目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性。方法选取2022年1月—2023年1月医院收治的脓毒症肺损伤患者80例,收集患者的一般资料、肺损伤相关指标[动脉血氧合指数(ratio of partial pressure of O_(2) in arterial blood to fraction of inspired oxygen,PaO_(2)/FiO_(2))、肺泡动脉氧分压差(alveolar-arterial oxygen gradient,P(A-a)O_(2))]及SOFA、APACHEⅡ评分情况,根据中医分型标准对脓毒症肺损伤患者进行分型,比较不同分型的脓毒症肺损伤患者以上各观察指标情况并分析相关性。结果脓毒症肺损伤患者以肺热壅痹证型占比最高、35.00%(28/80),其次为瘀血阻肺型27.50%(22/80),肺塞腑实型23.75%(19/80),水饮郁肺型13.75%(11/80)。不同证型的患者在性别、年龄方面差异均无统计学意义(P>0.05);不同证型的患者肺损伤指标PaO_(2)/FiO_(2)、P(A-a)O_(2)差异均有统计学意义(P<0.05);不同证型的患者SOFA、APACHEⅡ评分差异均有统计学意义(P<0.05)。肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺证型与PaO_(2)/FiO_(2)呈显著负相关(P<0.05),与P(A-a)O_(2)、SOFA评分、APACHEⅡ评分呈显著正相关(P<0.05)。结论脓毒症肺损伤患者中医证型主要为肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺,与肺损伤相关指标及SOFA、APACHEⅡ评分密切相关,掌握脓毒症肺损伤辨证分型特点并观察患者肺损伤相关指标及SOFA、APACHEⅡ评分变化,对疾病诊治及预后评估具有较高价值。
