The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined ...The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined shaft of a tunnel in Western Sichuan Province to analyze the damage characteristics of the initial support and propose a radial drainage and decompression treatment method.Field monitoring was conducted to assess the load and deformation of the initial support structure,and on-site investigations identified the distribution of cracked areas.In addition,numerical simulations were performed to evaluate the force and deformation characteristics of the initial support structure,which were then compared with field observations for validation.The variations in the lateral pressure coefficient and water pressure were evaluated.The results revealed that damage was primarily concentrated in the shoulder,spring line,and knee areas,with the bending moment at the knee increasing by up to 66.9%.The application of the radial drainage and decompression treatment method effectively reduced water pressure loads on the initial support.Post-treatment analysis indicated significant reductions in axial force and bending moment,enhancing structural stability.These findings provide valuable insights for improving the safety and durability of initial support systems in inclined shafts of high-hydraulicpressure railroad tunnels.展开更多
For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initi...For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initial support distance was proposed.First,based on the convergence-confinement method,a three-dimensional analytical model was constructed by combining an analytical solution of a non-circular tunnel with the Tecplot software.Then,according to the integral failure criteria of rock,the failure tendency coefficients of hard surrounding rock were computed and the spatial distribution plots of that were constructed.On this basis,the tunnel’s key failure positions were identified,and the relationship between the failure tendency coefficient at key failure positions and their distances from the working face was established.Finally,the distance from the working face that corresponds to the critical failure tendency coefficient was taken as the optimal support distance.A practical project was used as an example,and a reasonable initial support distance was successfully determined by applying the developed method.Moreover,it is found that the stability of hard surrounding rock decreases rapidly within the range of 1.0D(D is the tunnel diameter)from the working face,and tends to be stable outside the range of 1.0D.展开更多
This study investigated the mediating role of basic psychological needs satisfaction in relationship between teacher support and adolescents’personal growth initiative.A total of 493 adolescents(females=44.8%,mean ag...This study investigated the mediating role of basic psychological needs satisfaction in relationship between teacher support and adolescents’personal growth initiative.A total of 493 adolescents(females=44.8%,mean age=12.46,SD=0.57)completed the Teacher Support Scale,the Adolescents’Personal Growth Initiative Scale,and the Basic Psychological Needs Scale.The results,analyzed through a Mediation model analysis results indicated higher teacher support to be significantly associated with higher adolescents’personal growth initiative.Teacher support was also associated with higher basic psychological needs satisfaction.Basic psychological needs satisfaction mediated the relationship between teacher support and adolescents’personal growth initiative for higher personal growth initiative.Thus,enhancing students’perceptions of teacher support would support the student’s sense of proactive and resilient growth with basic psychological needs satisfaction.展开更多
In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the res...In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the research object to explore its load model,load characteristic curve,plastic zone,deformation,and critical thickness.Theoretical research and numerical analysis were conducted.The results indicate that under the same boundary conditions,the ultimate bearing capacity of the prefabricated assembly initial support is higher than that of the shotcrete initial support,resulting in larger ultimate deformation capacity of the prefabricated assembly initial support.Based on numerical calculations,the ultimate deformation and critical thickness of the prefabricated initial lining for single-and double-track railway tunnels are obtained when buried at depths of 200,500,and 900 m in rock masses of classes Ⅲ,Ⅳ,and Ⅴ.展开更多
The construction quality of the initial support of the tunnel excavation is directly related to the construction safety of the tunnel excavation. The project quality supervision agency shall check the initial support ...The construction quality of the initial support of the tunnel excavation is directly related to the construction safety of the tunnel excavation. The project quality supervision agency shall check the initial support quality inspection and evaluation standards, so as to provide a basis for the quality assessment of the initial support construction.Based on the initial support of the diversion water discharge tunnel excavation, the process and unit engineering division involved in construction quality assessment, inspection items, quality requirements, inspection method, and inspection quantity, mandatory construction quality inspection, technical requirements for the reference of the participating units and quality supervisors.展开更多
Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate support...Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate supports and the evaluation of their effectiveness.In a recent tunnelling project in the Akaishi Mountains of central Japan,displacement monitoring was intensively implemented to ensure the stability of the 4.2-km-long Hirogawara adit,excavated to a maximum depth of 832 m.Analysis revealed a strong correlation between initial and final displacements.However,the tunnel experienced occasional support deformations.To address this,the trend of 3D absolute displacements was analyzed to predict and evaluate asymmetric deformation.The effective use of 1-cycle displacement monitoring proved critical for predicting final displacements and optimizing rock supports,particularly in cases with high overburden and limited geotechnical information.展开更多
Numerous models have been proposed to reduce the classification error of Naive Bayes by weakening its attribute independence assumption and some have demonstrated remarkable error performance. Considering that ensembl...Numerous models have been proposed to reduce the classification error of Naive Bayes by weakening its attribute independence assumption and some have demonstrated remarkable error performance. Considering that ensemble learning is an effective method of reducing the classifmation error of the classifier, this paper proposes a double-layer Bayesian classifier ensembles （DLBCE） algorithm based on frequent itemsets. DLBCE constructs a double-layer Bayesian classifier （DLBC） for each frequent itemset the new instance contained and finally ensembles all the classifiers by assigning different weight to different classifier according to the conditional mutual information. The experimental results show that the proposed algorithm outperforms other outstanding algorithms.展开更多
Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a...Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a sparse algorithm for adaptive pruning LSSVR algorithm based on global representative point ranking(GRPR-AP-LSSVR)is proposed.At first,the global representative point ranking(GRPR)algorithm is given,and relevant data analysis experiment is implemented which depicts the importance ranking of data points.Furthermore,the pruning strategy of removing two samples in the decremental learning procedure is designed to accelerate the training speed and ensure the sparsity.The removed data points are utilized to test the temporary learning model which ensures the regression accuracy.Finally,the proposed algorithm is verified on artificial datasets and UCI regression datasets,and experimental results indicate that,compared with several benchmark algorithms,the GRPR-AP-LSSVR algorithm has excellent sparsity and prediction speed without impairing the generalization performance.展开更多
In the context of China’s proactive implementation of the Belt and Road Initiative(BRI),unraveling the BRI’s effect on corporate behavior is of vital importance to China’s policymaking on overseas investment.With t...In the context of China’s proactive implementation of the Belt and Road Initiative(BRI),unraveling the BRI’s effect on corporate behavior is of vital importance to China’s policymaking on overseas investment.With the BRI’s enactment as a quasi-natural experiment,this paper employs the difference in differences(DID)method to investigate the BRI’s effect on the financing constraint for Chinese enterprises.Our study finds that the BRI’s implementation has significantly reduced financing constraints for BRI enterprises,and the effect is more significant for emerging advantageous industries and export-oriented node cities.展开更多
In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tun...In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tunnel in Zihong village, Qi County as the research object, a numerical simulation method was used to establish a finite element model of the large section tunnel. So as to simulate and analyze the stress characteristics of the support structure of this tunnel. Through the simulation of the initial support and second lining of this large section tunnel in terms of displacement, stress, plastic zone damage and anchor shaft force, the results show that as the excavation progresses, the stress and displacement on the surface of the newly excavated tunnel profile is faster, especially at the side walls and arch footings, the stress and displacement values are slightly larger than other characteristic points, but the final values are stable and converge, and are basically consistent with the field monitoring results, which indicates that this support system is basically in stable state. Therefore, during the tunnel excavation and support process, special attention should be paid to the stability of the sidewalls and footings, and the results of this study will be of great practical significance for tunnel construction and maintenance.展开更多
In Nigeria, Universal health coverage has been sub-optimal due to limited access and inequality. This is worsened by poor health-seeking behavior due to out-of-pocket expenditure health system financing being practice...In Nigeria, Universal health coverage has been sub-optimal due to limited access and inequality. This is worsened by poor health-seeking behavior due to out-of-pocket expenditure health system financing being practiced by a greater percentage of the population. However, leveraging on the increasing population of Nigerian’s using communication technologies provides a viable and robust platform for improving patient’s care. Consequently, tele-health initiative provides a complementary approach to improving access to quality health and universal health system coverage. Tele-health initiative is Abia state’s input in progressing the Universal Health Coverage mandate of the Federal Government of Nigeria, anchored on the e-Health policy of Nigeria, after its adoption at the 58th NCH in Sokoto in 2016, of which Abia became the pioneer state for the Project. Abia state’s telecommunication market caters to almost 3.5 million active subscribers, making it the single largest provider of services in the state. Objective: The project is designed to ascertain the impact of the tele-health initiative on healthcare service coverage in Abia State. Methodology: This is a descriptive study with the quantitative and qualitative arm. The study was conducted in all the seventeen local government areas in the State. Result: 29,488 incoming calls were related to general health inquiries about basic information, counseling, and support that improved callers’ knowledge and attitude towards their health, concerns, and symptoms. Also, 66.8% of all calls (19,382) were for routine health information, complaints on mild everyday symptoms, chronic disease management, and follow-up care. About 29.6% of total calls (8751) were made by persons seeking information on socially stigmatizing topics and conditions.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42277165,41920104007)the Hubei Natural Science Foundation(Grant No.2023AFD217).
文摘The safety of the initial support during the construction of inclined shafts in tunnels traversing through high-hydraulic-pressure surrounding rocks is paramount.This study examines a high-hydraulic-pressure inclined shaft of a tunnel in Western Sichuan Province to analyze the damage characteristics of the initial support and propose a radial drainage and decompression treatment method.Field monitoring was conducted to assess the load and deformation of the initial support structure,and on-site investigations identified the distribution of cracked areas.In addition,numerical simulations were performed to evaluate the force and deformation characteristics of the initial support structure,which were then compared with field observations for validation.The variations in the lateral pressure coefficient and water pressure were evaluated.The results revealed that damage was primarily concentrated in the shoulder,spring line,and knee areas,with the bending moment at the knee increasing by up to 66.9%.The application of the radial drainage and decompression treatment method effectively reduced water pressure loads on the initial support.Post-treatment analysis indicated significant reductions in axial force and bending moment,enhancing structural stability.These findings provide valuable insights for improving the safety and durability of initial support systems in inclined shafts of high-hydraulicpressure railroad tunnels.
基金Project(2021JLM-49) supported by Natural Science Basic Research Program of Shaanxi-Joint Fund of Hanjiang to Weihe River Valley Water Diversion Project,ChinaProject(42077248) supported by the National Natural Science Foundation of China
文摘For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initial support distance was proposed.First,based on the convergence-confinement method,a three-dimensional analytical model was constructed by combining an analytical solution of a non-circular tunnel with the Tecplot software.Then,according to the integral failure criteria of rock,the failure tendency coefficients of hard surrounding rock were computed and the spatial distribution plots of that were constructed.On this basis,the tunnel’s key failure positions were identified,and the relationship between the failure tendency coefficient at key failure positions and their distances from the working face was established.Finally,the distance from the working face that corresponds to the critical failure tendency coefficient was taken as the optimal support distance.A practical project was used as an example,and a reasonable initial support distance was successfully determined by applying the developed method.Moreover,it is found that the stability of hard surrounding rock decreases rapidly within the range of 1.0D(D is the tunnel diameter)from the working face,and tends to be stable outside the range of 1.0D.
文摘This study investigated the mediating role of basic psychological needs satisfaction in relationship between teacher support and adolescents’personal growth initiative.A total of 493 adolescents(females=44.8%,mean age=12.46,SD=0.57)completed the Teacher Support Scale,the Adolescents’Personal Growth Initiative Scale,and the Basic Psychological Needs Scale.The results,analyzed through a Mediation model analysis results indicated higher teacher support to be significantly associated with higher adolescents’personal growth initiative.Teacher support was also associated with higher basic psychological needs satisfaction.Basic psychological needs satisfaction mediated the relationship between teacher support and adolescents’personal growth initiative for higher personal growth initiative.Thus,enhancing students’perceptions of teacher support would support the student’s sense of proactive and resilient growth with basic psychological needs satisfaction.
基金Research Project of China Railway Engineering Equipment Group Co.,Ltd.,Grant/Award Number:Equipment Research Cooperation 2019-14Postdoctoral Science Fund,Grant/Award Number:043201027。
文摘In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the research object to explore its load model,load characteristic curve,plastic zone,deformation,and critical thickness.Theoretical research and numerical analysis were conducted.The results indicate that under the same boundary conditions,the ultimate bearing capacity of the prefabricated assembly initial support is higher than that of the shotcrete initial support,resulting in larger ultimate deformation capacity of the prefabricated assembly initial support.Based on numerical calculations,the ultimate deformation and critical thickness of the prefabricated initial lining for single-and double-track railway tunnels are obtained when buried at depths of 200,500,and 900 m in rock masses of classes Ⅲ,Ⅳ,and Ⅴ.
文摘The construction quality of the initial support of the tunnel excavation is directly related to the construction safety of the tunnel excavation. The project quality supervision agency shall check the initial support quality inspection and evaluation standards, so as to provide a basis for the quality assessment of the initial support construction.Based on the initial support of the diversion water discharge tunnel excavation, the process and unit engineering division involved in construction quality assessment, inspection items, quality requirements, inspection method, and inspection quantity, mandatory construction quality inspection, technical requirements for the reference of the participating units and quality supervisors.
文摘Displacement monitoring provides essential information for safe and rational tunnel excavation.The data obtained allow engineers to analyze and predict tunnel behavior,facilitating the selection of appropriate supports and the evaluation of their effectiveness.In a recent tunnelling project in the Akaishi Mountains of central Japan,displacement monitoring was intensively implemented to ensure the stability of the 4.2-km-long Hirogawara adit,excavated to a maximum depth of 832 m.Analysis revealed a strong correlation between initial and final displacements.However,the tunnel experienced occasional support deformations.To address this,the trend of 3D absolute displacements was analyzed to predict and evaluate asymmetric deformation.The effective use of 1-cycle displacement monitoring proved critical for predicting final displacements and optimizing rock supports,particularly in cases with high overburden and limited geotechnical information.
基金supported by National Natural Science Foundation of China (Nos. 61073133, 60973067, and 61175053)Fundamental Research Funds for the Central Universities of China(No. 2011ZD010)
文摘Numerous models have been proposed to reduce the classification error of Naive Bayes by weakening its attribute independence assumption and some have demonstrated remarkable error performance. Considering that ensemble learning is an effective method of reducing the classifmation error of the classifier, this paper proposes a double-layer Bayesian classifier ensembles （DLBCE） algorithm based on frequent itemsets. DLBCE constructs a double-layer Bayesian classifier （DLBC） for each frequent itemset the new instance contained and finally ensembles all the classifiers by assigning different weight to different classifier according to the conditional mutual information. The experimental results show that the proposed algorithm outperforms other outstanding algorithms.
基金supported by the Science and Technology on Space Intelligent Control Laboratory for National Defense(KGJZDSYS-2018-08)。
文摘Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a sparse algorithm for adaptive pruning LSSVR algorithm based on global representative point ranking(GRPR-AP-LSSVR)is proposed.At first,the global representative point ranking(GRPR)algorithm is given,and relevant data analysis experiment is implemented which depicts the importance ranking of data points.Furthermore,the pruning strategy of removing two samples in the decremental learning procedure is designed to accelerate the training speed and ensure the sparsity.The removed data points are utilized to test the temporary learning model which ensures the regression accuracy.Finally,the proposed algorithm is verified on artificial datasets and UCI regression datasets,and experimental results indicate that,compared with several benchmark algorithms,the GRPR-AP-LSSVR algorithm has excellent sparsity and prediction speed without impairing the generalization performance.
基金Youth Program of the National Natural Sciences Foundation of China (NSFC) “Study on Underwriters’ Behaviors in the Full Life-Cycle of Corporate Bonds” (Grant No. 71802085)Youth Program of the National Humanities and Social Sciences Foundation “Study on the Promotion Incentives of SOE Executives and the Concealment of Corporate Bad News: Theoretical and Empirical Analysis” (Grant No. 18YJC630211)Youth Program of the Humanities and Social Sciences Research Foundation of the Ministry of Education “Study on the Economic Consequences of Corporate Investment and Financing Maturity Mismatch: Analysis Based on a Corporate Risk Perspective” (Grant No. 19YJC630232)
文摘In the context of China’s proactive implementation of the Belt and Road Initiative(BRI),unraveling the BRI’s effect on corporate behavior is of vital importance to China’s policymaking on overseas investment.With the BRI’s enactment as a quasi-natural experiment,this paper employs the difference in differences(DID)method to investigate the BRI’s effect on the financing constraint for Chinese enterprises.Our study finds that the BRI’s implementation has significantly reduced financing constraints for BRI enterprises,and the effect is more significant for emerging advantageous industries and export-oriented node cities.
文摘In order to study the stress characteristics of the initial support and secondary lining of the large section tunnel and to solve the problem of secondary lining cracking during operation. Taking the large section tunnel in Zihong village, Qi County as the research object, a numerical simulation method was used to establish a finite element model of the large section tunnel. So as to simulate and analyze the stress characteristics of the support structure of this tunnel. Through the simulation of the initial support and second lining of this large section tunnel in terms of displacement, stress, plastic zone damage and anchor shaft force, the results show that as the excavation progresses, the stress and displacement on the surface of the newly excavated tunnel profile is faster, especially at the side walls and arch footings, the stress and displacement values are slightly larger than other characteristic points, but the final values are stable and converge, and are basically consistent with the field monitoring results, which indicates that this support system is basically in stable state. Therefore, during the tunnel excavation and support process, special attention should be paid to the stability of the sidewalls and footings, and the results of this study will be of great practical significance for tunnel construction and maintenance.
文摘In Nigeria, Universal health coverage has been sub-optimal due to limited access and inequality. This is worsened by poor health-seeking behavior due to out-of-pocket expenditure health system financing being practiced by a greater percentage of the population. However, leveraging on the increasing population of Nigerian’s using communication technologies provides a viable and robust platform for improving patient’s care. Consequently, tele-health initiative provides a complementary approach to improving access to quality health and universal health system coverage. Tele-health initiative is Abia state’s input in progressing the Universal Health Coverage mandate of the Federal Government of Nigeria, anchored on the e-Health policy of Nigeria, after its adoption at the 58th NCH in Sokoto in 2016, of which Abia became the pioneer state for the Project. Abia state’s telecommunication market caters to almost 3.5 million active subscribers, making it the single largest provider of services in the state. Objective: The project is designed to ascertain the impact of the tele-health initiative on healthcare service coverage in Abia State. Methodology: This is a descriptive study with the quantitative and qualitative arm. The study was conducted in all the seventeen local government areas in the State. Result: 29,488 incoming calls were related to general health inquiries about basic information, counseling, and support that improved callers’ knowledge and attitude towards their health, concerns, and symptoms. Also, 66.8% of all calls (19,382) were for routine health information, complaints on mild everyday symptoms, chronic disease management, and follow-up care. About 29.6% of total calls (8751) were made by persons seeking information on socially stigmatizing topics and conditions.
