Experimental Study And Preliminary Application Of Damage Characteristics And Strength Of Cast In Place Concrete Under Impact Loading

This paper tends to the concrete curing process by the effect and influence of all kinds of Engineering Vibration Based on the engineering background,carried out research on the damage characteristics of concrete pouring and strength test under impact load and its preliminary application.Firstly,the theory of damage mechanics and statistics as the basis,the failure mechanism of concrete under impact loading the analysis,derive concrete statistical damage model based on age;at the same time,combined with the static load and impact analysis of dynamic load test and its results,obtained the concrete strength under impact load changes with age.Finally,also conducted a preliminary study of the main conclusions of this paper accordingly.The results are as follows:(i)Primary fracture formation of micro and meso process was carried out based on Mechanism Analysis of cracking of early age concrete under impact loading,analysis shows that the parameter and the degree of damage size of concrete under impact load,impact load and concrete elastic modulus and Poisson's ratio.(ii)On the basis of theoretical analysis,based on the statistical theory of Weibull probability distribution combined with viscoelastic model,combined with ultrasonic nondestructive testing theory of viscosity coefficient into time(age)coefficient,the dynamic damage constitutive model of concrete based on age.(iii)To carry out the new concrete specimen SHPB pressure bar impact and destruction test and analysis,test results show that all ages damage concrete impact compressive strength is about two times the static compressive strength,compressive strength of concrete and 7~14days impact to increase;to determine the different damage degree of weak age the damage analysis of the test results: 1~4 days was the weakest age,then 4~7 days after 14 d section,reducing the intensity of rate control in less than 5%.(iv)Through the concrete test observation and analysis of high speed camera impact SHPB pressure bar failure mode,failure has broken type failure modes of concrete impact that the shear stress strain and failure mode,failure mode,failure mode of tensile stress of four kinds of failure modes and failure modes of each.Age is not a single,usually 2~3combination of failure mode,but there is a tensile stress failure mode.(v)test and Analysis on blasting vibration of earthwork and blasting vibration based on the proposed early warning value and standard value,at the same time according to theblasting vibration velocity formula fitting,take the vertical direction as the control index of reverse calculation of single hole maximum explosive,and then draw the different age of concrete in different explosion parameters of drill center distance under the guidance and control of blasting construction,ensure the quality of concrete under influence of blasting vibration,concrete quality maintenance after forming qualified,bearing capacity can meet the design requirements.