Research Of Quality Control And Inspection Technology On Concrete Impervious Core

Based on abundant reading of domestic and foreign documentations, thisarticle researches on quality inspection pattern for concrete cutoff wallcombined with quality inspection control, vertical reflection, on surfacenon-destructive reconnaissance by transient electromagnetic methods and fewdestructive tomographic imaging. The research achievement has been appliedin quality control and inspection for concrete cutoff wall in attached dam ofHuangbizhuang reservoir in Hebei province, and good results have beenachieved. All this provides technical guarantees for construction qualityinspection for future large numbers of concrete cutoff wall projects. The mainresearches and achievements are as follows:(1) Analyze and further formalize normal quality inspection index andinspection methods used in concrete cutoff wall construction; In accordancewith the verticality required by construction specification and design ofconcrete cutoff wall, test method for construction slot hole inclination areanalyzed and researched, the strictness and feasibility of hole inclinationinspection by stacked hole inclination method are demonstrated; Inspectionindex and calculation methods of minimum joint thickness of stageâ… , stageâ…¡slot hole are analyzed based on design requirement of concrete cutoff wallthickness requirement and property of crossed circle.(2) Based on basic theory of elastic wave propagation, wave equation forpropagation of elastic wave in 2 dimension vertical inhomogeneous mediumof similar concrete cutoff wall model is developed. 2 dimension elastic sheetof concrete cutoff wall is established to research law and energy distributionrelations between propagation, attenuation, reflection and transmission ofelastic wave in concrete cutoff wall; Based on the concept of resolution, thecontent of vertical reflection method used to inspect concrete cutoff wallresolution is raised and factors will have influences on resolution are analyzed,expression of defective layer composite reflection factor and detectabledefective layer maximum thickness are developed; Relations between allsteps of sampling system of vertical reflection are build, the influence ofcentrum characteristics and receiving sensor on testing results are analyzed,therefore parameter requirements for testing instrument and parameter selection principle of collected parameters are raised. Based on the theory,model, resolution and testing technology, it is demonstrated that verticalreflection method used for testing of the quality of concrete cutoff wall is apractical, nondestructive and effective method and suitable for qualityreconnaissance.(3) In accordance with the characteristics of concrete cutoff wall, furthercomplete the theory system, data processing program and on situ observationsystem of transient electromagnetic method used in inspecting of cutoff wall;Concept and method of transient electromagnetic response and dispersion lawof transient electromagnetic field are established based on equivalentsubstation, formula of all area apparent resistivity and apparent depthparameters are developed and calculated, 2 dimensional resistivity imaging ofconcrete cutoff wall is conducted, the level of quantitative analysis of testingresults is improved.(4) Development and researching conditions of tomographic imaging,physical and mathematic foundations of concrete cutoff wall qualityinspection are summarized; Advantages & disadvantages of different raystracking technology and calculation are summarized, and straight and curvedray forward and inversion processing software of tomographic image arecompiled based on that; In accordance with the characteristics of concretecutoff wall, models with various defects are designed for forward andinversion analysis, accuracy of tomographic image used to inspect defects inconcrete cutoff wall is determined, measures to increase image resolution areforwarded; Void model is established to research the conditions of minimumresolution of tomographic image and relations between resolution capabilityand size and speed of anomalous body, the effectiveness of tomographicimaging for defect inspection of concrete cutoff wall is verified by concretemodel test; Nonlinear regression equation of wave speed and concretestrength is established based on testing data of standard modular wave speedtesting and compressive strength test, quantification level of tomographicimaging used in inspecting concrete cutoff wall is improved.