In the longitudinal seismic deformation method for shield tunnels,one of the most commonly used is the longitudinal equivalent stiffness beam model(LES)for simulating the mechanical behavior of the lining.In this mode...In the longitudinal seismic deformation method for shield tunnels,one of the most commonly used is the longitudinal equivalent stiffness beam model(LES)for simulating the mechanical behavior of the lining.In this model,axial deformation and bending deformation are independent,so the equivalent stiffness is a constant value.However,the actual situation is that axial deformation and bending deformation occur simultaneously,which is not considered in LES.At present,we are not clear about the effect on the calculation results when axial deformation and bending deformation occur simultaneously.Therefore,in this paper,we improve the traditional LES by taking the relative deformation as a load and considering the coordinated deformation of axial and bending degrees of freedom.This improved model is called DNLES,and its neutral axis equations are an explicit expression.Then,we propose an iterative algorithm to solve the calculation model of the DNLES-based longitudinal seismic deformation method.Through a calculation example,we find that the internal forces based on LES are notably underestimated than those of DNLES in the compression bending zone,while are overestimated in the tension bending zone.When considering the combined effect,the maximum bending moment reached 13.7 times that of the LES model,and the axial pressure and tension were about 1.14 and 0.96 times,respectively.Further analysis reveals the coordinated deformation process in the axial and bending directions of the shield tunnel,which leads to a consequent change in equivalent stiffness.This explains why,in the longitudinal seismic deformation method,the traditional LES may result in unreasonable calculation results.展开更多
Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underg...Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underground stopes was also studied. The random finite element method was used to analyze the probability of the rock mass stability degree of both pit slopes and underground stopes. Meanwhile, 3D elasto-plastic finite element method was used to research into the stress, strain and rock mass failure resulting from mining. The results of numerical simulation indicate that the mining of the underground test stope has certain influence on the stability of the pit slope, but the influence is not great. The safety factor of pit slope is decreased by 0.06, and the failure probability of the pit slope is increased by 1.84%. In addition, the strata yielding zone exists around the underground test stope. The results basically conform to the information coming from the field monitoring.展开更多
The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put f...The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put for-ward through analyzing the limitations of moving cone method under such conditions. With a view to recovering asmuch mineral resource as possible and making the maximum profit from the whole deposit, the new principle is tomaximize the sum of gain from both open-pit and underground mining. The mathematical models along the horizon-tal and vertical directions and modules for software package (DM&MCAD) have been developed and tested inTonglushan Copper Mine. It has been proved to be rather effective in the mining practice.展开更多
针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示...针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示原矿山法设计施工方案存在的不足,并基于此提出“矿山法结合地层冻结加固方案”和“机械顶管法施工方案”2种优化方案;随后在安全性、经济性、施工工期等方面对不同工法进行综合优选分析,同时引入碳排放指标进行绿色低碳评估。研究结果表明:1)机械顶管法在安全性和施工效率上优于其他方案,能够显著缩短施工周期;2)相比矿山法结合地层冻结加固方案,机械顶管法方案碳排放量减少了2 747.51 t CO_(2e)。展开更多
目的:利用数据挖掘技术分析针刺治疗痉挛型脑瘫的选穴规律及针刺方法应用特点,为临床针刺治疗痉挛型脑瘫提供选穴依据和治疗思路。方法:检索国家知识基础设施数据库(CNKI)、中国学术期刊数据库(CSPD)、中文科技期刊数据库(CCD)、中国生...目的:利用数据挖掘技术分析针刺治疗痉挛型脑瘫的选穴规律及针刺方法应用特点,为临床针刺治疗痉挛型脑瘫提供选穴依据和治疗思路。方法:检索国家知识基础设施数据库(CNKI)、中国学术期刊数据库(CSPD)、中文科技期刊数据库(CCD)、中国生物医学文献数据库(CBM)、PubMed、EMbase、Web of Science、Cochrane Library建库至2023年6月20日针刺治疗痉挛型脑瘫的临床研究文献,并进行描述性分析、关联规则分析和复杂网络分析。结果:纳入文献185篇,300条处方,219个腧穴,总频次为3229次。高频腧穴为足三里、百会、三阴交、四神聪、合谷等。特定穴以五腧穴为主;腧穴部位主要分布在头部和上下肢;经脉(包含针刺疗法)使用频次最高的为督脉、足阳明胃经、靳三针疗法等。支持度最高的腧穴组合是三阴交-足三里、四神聪-百会、曲池-合谷,均以局部配穴为主。“社团分析”共得到3个核心社团。临床治疗痉挛型脑瘫以毫针针刺最常见;针刺方法以平补平泻法为主,头部腧穴多采用平刺,体针采用直刺。结论:通过数据挖掘技术分析发现针刺治疗痉挛型脑瘫具有一定的特点,以局部选穴为主,同时配合上下配穴,重视针刺各流派特点,注重针刺方法效应特异性,为临床上针刺治疗痉挛型脑瘫提供参考。展开更多
基金the National Natural Science Foundation of China(Grant Nos.52130808 and 51878566)National Key R&D Program of China(Key Projects for International Science and Technology Innovation Cooperation between Governments,Grant No.2022YFE0104300).
文摘In the longitudinal seismic deformation method for shield tunnels,one of the most commonly used is the longitudinal equivalent stiffness beam model(LES)for simulating the mechanical behavior of the lining.In this model,axial deformation and bending deformation are independent,so the equivalent stiffness is a constant value.However,the actual situation is that axial deformation and bending deformation occur simultaneously,which is not considered in LES.At present,we are not clear about the effect on the calculation results when axial deformation and bending deformation occur simultaneously.Therefore,in this paper,we improve the traditional LES by taking the relative deformation as a load and considering the coordinated deformation of axial and bending degrees of freedom.This improved model is called DNLES,and its neutral axis equations are an explicit expression.Then,we propose an iterative algorithm to solve the calculation model of the DNLES-based longitudinal seismic deformation method.Through a calculation example,we find that the internal forces based on LES are notably underestimated than those of DNLES in the compression bending zone,while are overestimated in the tension bending zone.When considering the combined effect,the maximum bending moment reached 13.7 times that of the LES model,and the axial pressure and tension were about 1.14 and 0.96 times,respectively.Further analysis reveals the coordinated deformation process in the axial and bending directions of the shield tunnel,which leads to a consequent change in equivalent stiffness.This explains why,in the longitudinal seismic deformation method,the traditional LES may result in unreasonable calculation results.
文摘Slope stability is of critical importance in the process of surface-underground mining combination. The influence of underground mining on pit slope stability was mainly discussed, and the self-stabilization of underground stopes was also studied. The random finite element method was used to analyze the probability of the rock mass stability degree of both pit slopes and underground stopes. Meanwhile, 3D elasto-plastic finite element method was used to research into the stress, strain and rock mass failure resulting from mining. The results of numerical simulation indicate that the mining of the underground test stope has certain influence on the stability of the pit slope, but the influence is not great. The safety factor of pit slope is decreased by 0.06, and the failure probability of the pit slope is increased by 1.84%. In addition, the strata yielding zone exists around the underground test stope. The results basically conform to the information coming from the field monitoring.
基金Project (59704004) supported by the National Natural Science Foundation of ChinaProject (2000) supported by Foundation for University Key Teacher by the Ministry of Education
文摘The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put for-ward through analyzing the limitations of moving cone method under such conditions. With a view to recovering asmuch mineral resource as possible and making the maximum profit from the whole deposit, the new principle is tomaximize the sum of gain from both open-pit and underground mining. The mathematical models along the horizon-tal and vertical directions and modules for software package (DM&MCAD) have been developed and tested inTonglushan Copper Mine. It has been proved to be rather effective in the mining practice.
文摘针对在越江海高水压水下超大直径盾构隧道联络通道施工过程中缺乏足够的工程技术标准和案例经验、设计与施工面临众多挑战问题,以广州海珠湾超大直径盾构隧道区间的6条联络通道工程为例,对工程地质补勘资料及现场施工情况进行分析,揭示原矿山法设计施工方案存在的不足,并基于此提出“矿山法结合地层冻结加固方案”和“机械顶管法施工方案”2种优化方案;随后在安全性、经济性、施工工期等方面对不同工法进行综合优选分析,同时引入碳排放指标进行绿色低碳评估。研究结果表明:1)机械顶管法在安全性和施工效率上优于其他方案,能够显著缩短施工周期;2)相比矿山法结合地层冻结加固方案,机械顶管法方案碳排放量减少了2 747.51 t CO_(2e)。
文摘目的:利用数据挖掘技术分析针刺治疗痉挛型脑瘫的选穴规律及针刺方法应用特点,为临床针刺治疗痉挛型脑瘫提供选穴依据和治疗思路。方法:检索国家知识基础设施数据库(CNKI)、中国学术期刊数据库(CSPD)、中文科技期刊数据库(CCD)、中国生物医学文献数据库(CBM)、PubMed、EMbase、Web of Science、Cochrane Library建库至2023年6月20日针刺治疗痉挛型脑瘫的临床研究文献,并进行描述性分析、关联规则分析和复杂网络分析。结果:纳入文献185篇,300条处方,219个腧穴,总频次为3229次。高频腧穴为足三里、百会、三阴交、四神聪、合谷等。特定穴以五腧穴为主;腧穴部位主要分布在头部和上下肢;经脉(包含针刺疗法)使用频次最高的为督脉、足阳明胃经、靳三针疗法等。支持度最高的腧穴组合是三阴交-足三里、四神聪-百会、曲池-合谷,均以局部配穴为主。“社团分析”共得到3个核心社团。临床治疗痉挛型脑瘫以毫针针刺最常见;针刺方法以平补平泻法为主,头部腧穴多采用平刺,体针采用直刺。结论:通过数据挖掘技术分析发现针刺治疗痉挛型脑瘫具有一定的特点,以局部选穴为主,同时配合上下配穴,重视针刺各流派特点,注重针刺方法效应特异性,为临床上针刺治疗痉挛型脑瘫提供参考。
