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
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
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
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
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
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.
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.
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.
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.
