Model Building For Resistance Reduction In Grounded Deep Well Blasting And Its Application

This paper mainly establishes a simulation model for resistance reduction in deep well blasting,designs a program for solving grounding resistance in deep well blasting,and verifies the effectiveness of the two calculation methods.In addition,two examples of grounding resistance calculation methods are analyzed to maximize the economic benefits of the resistance reduction program.The main tasks completed are as follows:Firstly,the background of the model for deep well blasting is introduced.According to the morphological characteristics of the deep well,the ellipsoid,conductive rods,multiple conductive rods,spirals and other suitable models for deep well blasting are screened out,and their grounding resistance calculation results are compared,and the final determination is made.The deep well blasting model of multiple conductor rods is presented,and the algorithm theory of the model under different soil conditions is given.In addition,the verification of a single deep well blasting model under uniform soil and double-layer soil conditions proves the effectiveness of the two calculation methods.Finally,the influence of the number of conductor rods in the multiple conductor rod model on the grounding resistance is studied,and the corresponding graph is obtained.According to the rule of the graph,the number of conductor bars is recommended to be24.Secondly,the basic theory of blasting and deep well blasting are introduced,and it is verified that the 24 conductor rod model can simulate the actual blasting range.The procedure for solving the grounding resistance of the grounding system of the substation with grounding grid under the conditions of uniform soil and double-layer soil is given.Comparing the numerical calculation and program calculation results,the error rate of the result is within 5%.Draw a graph of the law of grounding resistance varying with the radius and depth of the deep well under the condition of uniform,double-layered soil.Through the study of the graphs,it is concluded that under uniform soil conditions,the grounding resistance decreases with the increase of the depth of the deep well or the radius of the deep well,and the rate of change becomes smaller and smaller.For double-layered soil,as the radius increases,the ground resistance change rate becomes smaller and smaller,indicating that when the radius increases to a certain extent,the increase in the radius has little effect on the ground resistance.For double-layered soil,when the depth of the deep well does not exceed the thickness of the first layer of soil,the deeper the depth of the deep well,the better the resistance reduction effect per unit depth.When the depth of a deep well exceeds the interface,the resistance reduction effect per unit depth gradually deteriorates.Finally,combined with the example data of a 110 kV high soil resistivity in a uniform soil and double-layer soil substation in Zhejiang,numerical calculation methods and program calculation methods are used to solve the grounding resistance.The error rate obtained by the two methods is within 5%,which proves the two calculations Effectiveness of the method.In order to improve the economic effect of deep well grounding resistance reduction,based on the actual data of the substation,two optimization design schemes are specifically introduced: One is to reduce the cost of resistance reduction by optimizing the radius and depth under a certain resistance value.The second is to reduce the grounding resistance by optimizing the deep well blasting radius and deep well depth.Taking the grounding resistance calculated from the original data of the example as a reference,the cost of using the first optimization scheme to reduce the resistance is 28.5% of the original example result,and the second scheme is used to reduce the resistance to 89.2% of the original grounding resistance reference value,which is to improve deep well blasting.The economic benefit of grounding resistance provides a new idea.Finally,combining the actual project and considering other costs,the calculation function of the deep well blasting cost in line with the actual project is obtained.