Research On Concrete Spiral Pipes Pressure Reduction Conveying And Pipe Impact Wear Control In Deep Shaft

Deep shaft as the main throat of deep mining engineering,There is a huge demand for concrete during the construction of deep shafts,Traditional bucket conveying is difficult to meet engineering needs because of long preparation time,intermittent work and low efficiency.Concrete pipeline self-sliding conveying is expected to become the main method of concrete delivery in deep shafts as the advantages of large conveying capacity and high efficiency.But the problems of excessive pressure in the pipe and wear of the pipe are still needed to be solved.Because the existing concrete straight pipe pressure reduction conveying mode cannot adapt to the defects of restricted wellbore space conveying,this method is difficult to apply in the field of deep vertical shaft concrete transportation.This article tentatively carry out research on spiral pipe pressure reduction and pipe impact wear control of deep shaft concrete transportation.The results have very important basic engineering significance for the future development and engineering application of shaft construction technology with a depth of more than one thousand meters.The content of the paper is one of the main contents of the national key research and development,"Key Technologies and Equipment for Efficient Digging and Formation of Deep Shafts in Metal Mine"(No.2016YFC0600802)"Optimization of Wear Reduction and Antisegregation Concrete Transportation Process".Restricted by the existing " Non-ferrous metal mine shaft construction engineering specifications ",the construction party cannot carry out the relevant test work on site until the new technical standard specification for a thousand-meter deep well is formed.The paper mainly adopts on-site investigation,theoretical analysis,numerical simulation and other methods to carry out related research.The main content of the paper is as follows:(1)Based on the on-site investigation of the deep vertical shaft concrete transportation project of a large-scale metal mine,the factors that affect the impact and wear of the pipeline the pressure such as aggregate characteristics and pipeline characteristics are analyzed based on the impact and damage forms of the pipeline.Then a spiral pipe pressure reduction conveying scheme for concrete s in deep shafts is tentatively proposed.(2)Construct the model of spiral pipes pressure reduction conveying of deep shaft concrete transportation and study the efficiency of depressurization of single-section spiral pipe self-sliding conveyor.Evaluate the efficiency of pressure reduction conveying and derive its expression by introducing the decompression coefficient K,the influence of the structural factors of the spiral pipe on the decompression coefficient is analyzed.(4)Construct a stepped spiral pipe pressure reduction conveying model of deep mine.Study the safety distance between adjacent devices based on the theory of full pipe flow and derive the calculation formulation of reasonable safety distance,the influence on the safety distance from two angles of structural parameters and flow velocity is analyzed.(5)Study the feasibility of controlling the impact wear of the pipeline.The control measures of pipeline impact and wear are proposed from the three aspects of internal pressure,aggregate characteristics and pipeline characteristics combining the impact factors of pipeline impact and wear.The results provide technical guidance for the safe transportation of concrete in deep vertical shaft pipes.The research results hope to provide a new idea and method for the efficient delivery of concrete in the construction of deep wells in our country,and to promote the progress of construction technology of vertical wells more than thousand meters in depth.