| Coal is the pillar energy in our country,and it will occupy the main position in the primary energy structure for a long time.At present,the underground coal resources mainly adopt the "121" long-wall mining method(mining a working face,digging two mining roadways and setting up one coal pillar).There are many problems such as waste of coal resources caused by setting up coal pillars,high production cost of roadway excavation and frequent occurrence of large deformation disasters in high stress environment,which seriously restrict the safe and efficient mining of coal resources in China.Therefore,vigorous development of gob-side entry retaining technology has become the main trend of mining industry at home and abroad.However,the research on project management and techno-economic evaluation of self-made roadway without coal pillars still needs to be carried out.For this reason,this paper takes the project of self-made roadway without coal pillars as the actual engineering background,comprehensively uses the research methods of on-site investigation,theoretical analysis and on-site practice,and integrates the knowledge of coal mining theory,engineering mechanics,engineering management and technical economics to carry out the management and control of the project of self-made roadway without coal pillars and technical and economic feasibility analysis.The research mainly focuses on the following points:(1)By summarizing the development history of coal mining theory and technology,this paper briefly describes the formation of self-formed roadway mining technology without coal pillars,and emphatically analyses its technical advantages,field application and geological influencing factors.By building mechanical model,the paper analyses that the technology of self-formed roadway without coal pillars has obvious technical advantages compared with traditional gob-side entry retaining technology,that is,the length of lateral cantilever is reduced by cutting roof,and the harm becomes beneficial.The roadway is formed automatically by working under rock pressure,which eliminates the existence of remaining coal pillars/rock pillars and reduces the occurrence of mine disasters.Experts from different research fields are invited to grade it,and the key factors affecting the project of self-formed roadway without coal pillars are determined through two grades,and the order of primary and secondary effects is determined.(2)From the point of view of project management and control research,this paper analyses the characteristics of self-made roadway project without coal pillar,the main contents of project cost management,quality management and time limit management,defines the management objectives,and formulates the management system of self-made roadway project without coal pillar.The earned value method is used to analyze the key points of project cost management and the method of controlling project cost.At the same time,the project budget is adjusted in time according to the actual working conditions in order to prevent the actual cost from exceeding the total project budget.For the management of project quality,the project quality is strictly controlled by establishing the whole staff quality management system,the whole process quality management system and the total quality management system.Management can ensure the quality of the project.In the aspect of engineering management,this paper studies the management and control methods of construction layer and management layer,and compiles corresponding project progress icons so that both sides can grasp the project progress in time,have special problems,adjust the working procedures in time,and complete the self-made roadway project without coal pillars as soon as possible.This paper summarizes the factors affecting the project management of self-made roadway without coal pillars,and expounds the relationship between the factors and the project management and control.(3)Through the technical and economic feasibility analysis of the project of self-formed roadway without coal pillars,it can be seen that the technology of self-formed roadway without coal pillars is a new technology without coal pillars,which is based on the theory of cutting roof short arm beam.The technology takes the two-way gathering energy pre-cracking of roof and large deformation support of constant resistance as its core,ensures the stability of roadway along goaf,and has advanced theoretical feasibility.At the same time,Dafu can reuse the existing equipment,save the early investment of the project in time,simple construction technology,low labor intensity,and can quickly increase production;through the optimization design of the core technology and process,it can greatly increase the construction period and save the cost of the project;through the study of the economic factors in the technical and economic analysis,this article clarifies the project.The project is a project with small investment,low cost and short payback period.The technical and economic comprehensive analysis of different support design schemes for mining roadways is carried out.Firstly,the basic principles of technical and economic evaluation and the basic conditions for technical and economic comparison are defined.The optimum applicable conditions of technical schemes for self-formed roadways without coal pillars are analyzed,and three kinds of design of mining roadways are estimated by using cost present value method based on typical applied mining areas in the field.The cash flow under the scheme is analyzed concretely;then the structure model of tomographic analysis is established by using AHP method,and the three schemes are comprehensively evaluated by using the method of fuzzy comprehensive evaluation;at the same time,the uncertainty analysis is carried out in combination with the actual project,with emphasis on the analysis of relevant factors,and the sensitivity analysis of the main influencing factors.Coal pillar-free self-made roadway mining technology has been written into the State Council's Opinions on Overcapacity Resolution and Difficult Development of the Coal Industry(Guofa[2016]7)and the Energy Production and Consumption Revolution Strategy(2016-2030)(Development and Reform Foundation[2016]2795),which are advanced mining technology mainly promoted at the national level.However,no research has been carried out on the management and technical and economic evaluation of the self-made roadway project without coal pillars.Based on this,this paper carries out the research on the project management and technical and economic evaluation of the self-formed roadway without coal pillar,determines the key factors and their order affecting the self-formed roadway without coal pillar,establishes a comprehensive project management system,optimizes the construction process,and evaluates and optimizes the mining schemes under different geological conditions,which can provide decision-making reference for coal enterprises.It also provides a theoretical basis for the formulation of relevant industrial policies by the state. |
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