Study On The Strength Evaluation Theory Of Concrete Drainage Pipe Structure

At present,most of the evaluation methods of concrete drainage pipeline use video detection,sonar detection and other visual detection methods to collect the impact data of the damaged parts of the pipeline,and then grade the defective parts of the pipeline by the way of subjective endowing.Finally,the defect parameters obtained by this way are used to calculate the structural health status of the pipeline section,and to calculate the working load of the pipeline and the pipe However,the nature of the pipeline structure state,such as the aging of the material and the residual strength of the defective parts,has not been mentioned.Therefore,the evaluation results of the calculated pipeline can not give reliable suggestions on whether the pipeline needs structural repair and replacement.In order to solve the above problems,this paper has done the following work:(1)This paper analyzes the kinds of loads that the buried concrete drainage pipeline will receive in theory,selects its main bearing load according to the actual situation of the existing pipeline,regards the pipeline in service as a three-way stress state,and selects Tresca yield criterion and von Mises yield criterion as the failure conditions of the pipeline from many failure criteria,and calculates the minimum strength of the pipeline under the working load.(2)According to the maximum tensile strength of concrete used in plain concrete pipeline,the product of the design strength of reinforced concrete pipeline and the conversion coefficient of reinforcement ratio is the yield strength of two kinds of pipeline respectively.Combined with the prediction model of residual strength of pipelines with various defects,the residual strength at the defects is calculated.So we can objectively calculate and evaluate the serious situation of the defective part of the concrete drainage pipe.In order to facilitate the evaluation work,matlab can be used to program the relevant calculation steps and design a special calculation software.This paper also gives the process and examples.(3)This paper analyzes the problem of pipeline settlement caused by the excavation of underground engineering around the pipeline.From the point of view of controlling the surface settlement,the calculation method of the maximum surface settlement based on the allowable stress of pipeline material and the allowable maximum opening value of pipeline interface is given,which can evaluate the structure under the condition of pipeline settlement.(4)In this paper,the aging of concrete drainage pipe material is corrected by the method of measured elastic modulus,and the existing drainage pipe structure evaluation code is improved accordingly.