As a new technology to optimize the schedule of construction projects in the field of construction in recent years,the key chain technology can better solve the time cost problem of schedule management in the use of interspersed construction projects.On the basis of understanding the principle and advantages and disadvantages of the key chain technology,this paper compares it with the traditional schedule management method,which reflects the superiority of the key chain technology.Through the comparison of traditional construction methods and interspersed construction methods,it is found that interspersed construction can greatly reduce the waste of resources,shorten the construction period and other advantages.Based on the above research,this paper takes the No.6 building of a community in Ji'an City,Jiangxi Province as an example to study the combination of the two,which reflects the effect of"1+1＞2"in progress management.The research shows that the key chain technology can effectively shorten the construction period,make full use of resources,make the whole project more scientific and perfect,and has certain reference significance for the project using interspersed construction technology.
Efficient mining of multi-layer ore body has always been a technical problem in the mining field.In this paper,taking an iron ore mine as an example,through the technical research of a variety of mining methods,the upward horizontal stratified point pillar filling mining method in the multi-ore body assemblage area is determined as the final mining method.The application practice shows that the mining method has the advantages of large production capacity,concentrated operation,convenient management,less mining engineering,etc.The production capacity of the panel can reach 435 t/d,the stope loss rate is 18％,and the depletion rate is 8％.It provides technical support for the comprehensive utilization of resources under complex mining technology conditions,and has a certain guiding role for similar mining at home and abroad.
At present,the antimony ore in China has high development intensity,and insufficient back-up resou-rces.Therefore,studying the optimal benefication flowsheet of recovering antimomy is of great significant to rational development and utilization of antimony ore resources.In this paper,the experimental study on the beneficiation process of recovering antimony from antimony ore is carried out,and the effects of grinding fineness,activator,collector,inhibitor and flotation process on the beneficiation effect of antimony recovery are investigated.The advanced and scientific beneficiation processes,parameter indicators,and reagent system is formed,providing a basis for the rational development and utilization of this type of ore.The results show that the antimony concentrate with antimony grade of 48.84％and antimony recovery of 94.12％can be obtained through the closed-circuit beneficiation process of"one roughing,one scavenging,three cleaning,middling ores sequential returned",realizing the high efficient recovery of antimony,and the experimental results have reference value.The optimum processing conditions are as follows:grinding fineness is-0.074 mm 60.63％;the activator is lead nitrate;the inhibitor is CTY;the collector is ethyl sulfur nitrogen and No.25 black powder;the foaming agent is MIBC.
The total treatment capacity of a large chemical sewage treatment plant in Zhejiang Province was 2.88 × 105 m3/d with the completion of the second phase.The plant underwent technological expansion(1.3 × 105 m3/d)based on the first-phase project in 2019,resulting in a sewage treatment capacity of 2.74 × 105 m3/d,which was later increased to 4.18 × 105 m3/d with the completion of the second phase.The effluent released from the plant meets the Class A discharge standard"Pollutant Discharge Standard for Urban Sewage Treatment Plants".After analyzing the emission standards and expansion,and taking into account the land use and actual operation situation,the first-phase expansion biochemical treatment process utilizes the original activated sludge and contact oxidation process from the first-phase sewage treatment plant to remove COD,ammonia nitrogen,and other organic substances.The denitrification process uses the carrier flow bed biofilm treatment process to remove TN indicators.The effluent is stable and superior to the design discharge standards after the upgrading and reconstruction.The upgrading and renovation project maximizes the use of the original factory buildings and available land,resulting in low investment and operating costs,short renovation periods,efficient and stable operation,and positive social and economic benefits.This project provides a valuable reference for other sewage treatment plants seeking similar upgrades and renovations.
It is very difficult to conduct precise seismic damage analysis on complex structures,the multilevel sub-model technology can quickly focus on the weak parts of the structure and perform precise analysis,due to the small size of the sub-model,precise analysis is easy to achieve,the applicability of multilevel sub-model technology in precise analysis of seismic damage in complex structures is studied.The mechanical principles of sub-model technology and the establishment method of multilevel sub-models are elaborated,and the calculation process of multilevel sub-models is introduced.A 40 story frame-corewall structure with outriggers is designed by PKPM according to the 7 degree fortification standard.The structure is subjected to seismic damage analysis using multilevel sub-model technology by ABAQUS.The yield mechanism of the structure is analyzed using the floors near the strengthening layer as the first level sub model.Three important parts,including reinforced layer beam column joints,are selected to establish a secondary sub model,and the development process and damage morphology of joint cracks are analyzed.The calculation shows that the multi-level sub-model technology can quickly focus on the weak parts of the structure and has good adaptability in seismic damage analysis of complex structures.
Section lifting construction technology of steel box girder is widely used in bridge construction.Section lifting construction makes the construction of steel box girder bridge more safe and efficient,and the linear state and stress level of steel box girder should be in a safe and controllable state during construction.Based on the ZL23 joint main line bridge of the high-tech three-way(three-ring road-outer Ring Road)renovation and upgrading project,the steel box girder full bridge model and sub-segment fine analysis model were established by using finite element software.According to the stress state and deformation of the main beam in different construction stages,the construction safety performance of the steel box girder segment is analyzed.The lower edge stress and vertical deflection of the full joint and each stage met the requirements.It has great guiding significance for the installation and construction of steel box girder,which can also provide reference for similar steel box girder construction.
Water,as a direct construction disturbance factor,plays an important role in evaluating and analyzing the stability of foundation pit slope engineering.This article mainly focuses on deep backfill soil.The mechanical parameters of backfill soil under different moisture contents are measured through static triaxial shear tests,and direct shear tests are conducted on backfill soil under different cycles in a simulated saturated water loss environment.The degradation effect of deep backfill soil construction disturbance water is deeply studied.The research results show that the cohesion,internal friction angle,and shear strength of backfill soil all decay with the increase of water content.The attenuation law of cohesion and internal friction angle shows a linear and then gentle trend,while the attenuation trend of shear strength gradually slows down;The mechanical parameters of backfill soil decrease with the increase of the number of dry wet cycles,especially the attenuation degree is most significant at the first time,and finally tends to a certain value.The deterioration coefficient follows a negative exponential function relationship with the number of cycles.Studying and analyzing the damage mechanism of water induced deterioration in construction disturbances on fill soil provides theoretical support for the stability evaluation and disaster mitigation of foundation pit engineering.
In order to strengthen the safety accident management capability and improve the safety production situation in construction,the article quantitatively analyses the correlation between the number of safety accident casualties and different safety accident types in China's construction projects in recent years through the method of grey relation analysis,and concludes that several accident types such as fall from height and object strike have a high relevance with the number of accident casualties.By analyzing the inducement factors of different types of accidents,this paper summarizes the existing safety risks in the construction process,and puts forward some suggestions and measures to improve the construction safety situation,providing reference for the safe construction of construction projects.
In view of the problem of dangerous rock mass on the slope of Hongmen section of Suichuan,G105,due to the influence of rainstorm,the formation mechanism of dangerous rock mass is analyzed from the aspects of terrain,formation lithology,geological structure and control of external dynamic action,according to the site survey and 3D radar scanning of the manifestation of dangerous rock mass and the causes and consequences of the formation of geological disasters,and the stereographic projection of dangerous rock mass is drawn through field investigation and analysis,and the stability coefficient of dangerous rock mass is quantitatively analyzed,The results show that the results of qualitative analysis and quantitative analysis are basically consistent,and the combination of qualitative and quantitative methods is a reliable method in design,which can provide corresponding basis for design.
In the process of engineering construction,there are a large number of high-altitude operations such as lifting and splicing,which often have high risks.The parallel and multi-dimensional working space often leads to the occurrence of high-altitude falls.In China,safety accidents caused by high-altitude falls during construction are not uncommon.In an effort to improve the safety of high-altitude construction work in China,a risk assessment index system for high-altitude work accidents in construction projects has been established from five aspects:human,material,management,environment,and technology.This article uses the analytic hierarchy process to determine the weights,and then uses the matter element extension model to obtain the comprehensive correlation and evaluation results of the risk of falling from heights in construction projects.Taking a certain building project as an example,the results show that the method proposed in this article is more objective and can effectively identify the risk level of high-altitude operations in the project.The overall risk of the project is low,but there is a trend towards moderate development.Compared with traditional risk level assessment methods,the risk assessment results are basically consistent,verifying the feasibility of the model proposed in this article.
The geological conditions of the exploration and construction site ofa certain Chong coal mine are complex,and the fissure karst cave is very developed.In the process of drilling in this area,the mud leakage is serious,the bottom hole accidents occur frequently,the drilling construction is difficult and the cost is high.Aiming at the problem of plugging in this area,through theoretical and Experimental Research on foam vegetable gum drilling fluid,the optimal formula is confirmed.The results show that 3.5％vegetable gum+0.3％sodium dodecyl benzene sulfonate+0.05％polyacrylamide foam vegetable gum drilling fluid has strong rock powder carrying capacity,high drilling efficiency and significant plugging effect,which provides theoretical and practical guidance for plugging in complex formations.
Curved beams are widely used in building structures because of their beautiful shapes.Under the action of vertical loads,the curved beam is usually in a complex state of coupled bending,shear,and torsion,and its safety performance has aroused concern.In this paper,taking a concrete curved beam and slab structure of high-rise building as an example,a method is developed to evaluate whether the structure meets the design load standards and requirements of serviceability limit state.First of all,the in-situ static loading test under part of normal service loads is carried out to test the working performance of the structural members.Then,the ABAQUS is used to establish the finite element analysis model of the arc beam and slab structure,and the stress simulation and results comparison under the same working conditions of the test are carried out.Considering all normal service loads,the finite element analysis of arc beam and slab structure is carried out to complete the mechanical performance evaluation of this type of structure.The results show that,considering the normal service load,the deformation of the test arc beam and slab is less than the limit value in the specification and there is no obvious crack,and the stress and strain of both the reinforcement and concrete are small,which meets the requirements of the serviceability limit state.
土层弹性模量一般难以通过现场勘探或室内试验得到,而开展位移反演分析具有相对优势.本文融合BP神经网络算法优化和有限元软件ABAQUS建模技术,借助ABAQUS软件中的python语言接口 自行编程,以MATLAB工具箱为平台,对非均质土层的弹性模量开展位移反演分析,并预测桩基后续沉降.研究结果表明:土层弹性模量反演值与土层压缩模量地勘报告值之间存在潜在的数学函数关系;桩基沉降预测值与现场试验监测值高度吻合,并且桩基沉降预测值大于现场试验监测值.本文成果可为提高桩基沉降的预测效率,为后续的施工设计调整提供数据支撑.
为了丰富国内典型微细粒嵌布铁矿石分选指标差、铁精粉品位低等生产问题的解决方案,本文以国内某微细粒嵌布铁矿石为研究对象,基于矿石组分和物相性质,系统性研究了磨矿条件、磁场强度和选别工序对铁矿石磁选的影响.研究结果表明:铁矿石原矿中铁元素主要以磁铁矿的形式存在,分布率达69.25％,脉石矿物以绿泥石为主.在磨矿细度＜37 μm占比为90.02％的条件下,采用"一粗两精"的弱磁选工艺可获得铁品位为62.30％,回收率为59.57％的分选指标.该研究提出了 一种技术可行性良好的磁选工艺,为微细粒嵌布型磁铁矿石分选工艺研究提供技术参考.
透水钢渣沥青混合料路面既具有排水沥青混合料的透水和降噪功能,又兼具钢渣的抗滑、与沥青间黏聚力强的功能,且符合国家大力发展海绵城市的大政方针.为进一步分析透水钢渣沥青混合料路面的各项力学性能,本文采用颗粒流软件,通过不规则多面生成技术,生成具有级配特征、特定空隙率的不规则集料颗粒模型,并通过室内单轴压缩试验和动态模量试验,标定模型内部不同接触之间的细观接触模型的细观接触参数.本文研究成果可为透水钢渣沥青混合料路面的力学性能分析提供借鉴.
城市景观桥梁设计需要同时兼具桥梁功能性和环境协调性.针对异形景观天桥的设计难点,本文以景观要求较高的聊城市利民西路人行天桥工程为研究案例,详细描述了工程背景、项目定位、方案整体构思、景观设计思路,并根据天桥景观特点和工程特点,阐释了该桥上、下部结构设计方案,以及在结构设计过程中所面临的受限点与创造性解决方案.本文内容可为类似非常规景观人行天桥的设计提供有益的经验和启示.
居住区绿地作为居住区景观的重要组成部分,具有美化环境、改善居住区内微气候等功能.其中,宅间巷道因其普遍性、空间有限性、效果多样性,其景观设计、施工、养护难度较大,因此更具研究价值.基于上述原因,本文以明德兰庭项目为例,讨论在北方巷道景观设计、施工过程中,如何因地制宜、合理地进行苗木种类选择和种植设计,提升种植施工及养护管理,确保巷道种植景观的效果呈现;总结项目在种植设计及施工时的注意要点,为北方城市居住区巷道苗木种类选择、植物组团配置、空间布局和施工养护提供实践参考.
装配式建筑是未来建筑业发展的趋势,全过程工程咨询对装配式建筑的推广普及有着重要意义.为推动我国装配式建筑行业的发展,本文基于专家咨询和政策分析,构建SWOT-PEST模型,从政治、经济、社会、技术的角度,分析装配式建筑采用全过程工程咨询服务的优势、弱势、机会、制约,借助SWOT-PEST矩阵,提出加强政府政策引导、企业建立培养激励制度、完善联合体利润分配制度、抓住"一带一路"战略机遇等几点对策.本文成果可为提高全过程工程咨询服务质量和促进装配式建筑行业持续发展提供一定的借鉴与参考.
为合理确定新增一批师生后需新增一体化污水处理设施规模大小,本文基于水库调洪演算原理,设计出3种方案,并对比分析各方案需新增污水处理设施和(或)调节池规模的大小.结果表明:1)仅增大调节池容积方案不可行;2)仅增加一体化污水处理设施方案、同时增加一体化污水处理设施和调节池容积方案可行.本文成果可为合理确定一体化污水处理设施规模等问题提供一定的借鉴与参考.
为研究双线盾构隧道先后开挖对结构稳定性以及两者相互作用的影响,本文以厦门市翔安行政中心站——浦边站为工程背景,采用有限元软件Midas-GTS建立模型,分析双线隧道先后开挖对盾构管片、箱涵结构以及地表沉降的影响,对比隧道加固前后箱涵结构的关键点沉降变化规律.研究结果表明:1)双线隧道开挖完成后,左右线隧道正上方处箱涵结构沉降最大,分别为6.74、6.14 mm,箱涵结构正下方处的隧道管片变形最小;2)箱涵结构限制了土体的竖向位移,使土体产生横向变形,导致开挖后沉降槽宽度增大至30 m,最终地表沉降呈现"U"形;3)在隧道下穿箱涵范围内对隧道进行环向注浆加固,可保证箱涵结构的稳定.本文成果可为今后双线盾构隧道施工提供一定借鉴.
