Study On Concrete Dynamic Characteristic Of Dagangshan Arch Dam By CT Test

This paper uses the actual mix material and mix of concrete of Dagangshan hydropower hyperbolic arch dam to manufacture samples, carrys out the study of its concrete's dynamic and static characteristic based on CT Test to reveal the difference of the concrete failure process between the conditions of static and dynamic, in order to provide base value for seismic stability analyzing of the project.This paper firstly introduces the background and the development of concrete CT experiment, points out that the most important problem on present is the little test quantities which can't obtain the regular knowing about the concrete's failure process. So, needs a perfect concrete CT test system, solves the technical problems appeared from the test, enlarges the test quantity in order to study the concrete's static and dynamic characteristic of the Dagangshan project.Then the paper describes in detail the components, technical specifications, various test methods of operation and technical essentials of the concrete CT test, and points out problems in the experiment and proposes relevant solutions, that are(1):Problems of samples' nonstandard, the solution is sampling by boring samples; (2):Problems of samples'alignment when bonding, the solution is using the methods of loosening one side when clenching the others; (3):Problems of samples'cementation, the solution is using JGN-â…¡structural adhesive; (4):Problems of samples'installation;(5):Problems of big samples'cementation instability, the solution is developing new aluminum bonding plate;(6):Problems of dynamic experiments' loading curve's nonstandard, solution is change the past tensile load into combination of tension and compression.Based on the medical CT scanning system and the special design and manufacture portable test device the static and dynamic real time CT tests for concrete specimens under tensile and compressive loading has been carried out. The provided CT images verified the expected requirements to the designed CT test system. Cracks in CT images were distinguished and their morphology characters are analyzed based on CT physic theory and image processing technique. The difference of cracking process between the static and dynamic compression loading conditions was investigated in detail.Some conclusions can be derived as follows:(1):Repeatability of the macro-curve gained by concrete CT test was fine so that this test system fitted for the test requirement.(2):Gained the cracks'expansion process by analyzing the concrete's CT images.(3):Obtained cracks arisen at many parts of the concrete under dynamic when single under static, crack was straighter than that under static, and the dynamic strength of the material was brought in to full play.(4):Stated the CT values of the chose different regions on cross section. By comparison, changing magnitude of CT mean and variance in rent region was higher than the whole region, showed that damage in rent appeared earlier than the whole region after the sensitive strength.This paper establishes the foundation for the further study on the dynamic characteristic of concrete by analyzing and comparing the loading technology and the failure mode of concrete's tensile and compress under the condition of static loading...