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.
