Research On Test Of The Dynamic Constitutive Properties And Numerical Analysis Of Pouring Asphalt Concrete

Pouring asphalt concrete core wall dam have many advantages of construction convenient and beingconstructed in cold condition, more and more widely used. But China is a country of many earthquakes. Thedistribution of range of seismic activity is wide. Seismic source is shallow and have great destructive power.So seismic properties of pouring asphalt concrete core wall dam is an urgent need to solve the problem inearthquake prone areas construction.The method of combining the experimental research, the theoretical analysis and numerical simulationwas used. First of all, dynamic constitutive properties of pouring asphalt concrete was studied from thematerial level; Pouring asphalt concrete core wall dam was analyzed in the static and dynamic calculation andseismic safety from the aspect of structure evaluation. This paper discussed the influence law of dynamicresponse of the different thickness of covering layer to core wall dam. On the basis of it, the sensitivity of thestatic and dynamic constitutive model parameters to pouring asphalt concrete was analyzed. The main researchcontent is as follows:(1) Test research of dynamic constitutive properties of pouring asphalt concrete. Pouring asphalt concretematerial in Xinjiang was used to the constitutive property test, and studied the changing rule of the stress-strain,dynamic elastic modulus and damping ratio of pouring asphalt concrete material. Under the condition of theasphalt content of9.0%and9.0%, the paper discussed the influence of different confining pressure, theprincipal stress ratio and frequency to the stress-strain, dynamic elastic modulus and damping ratio. Researchresults showed that: Change rule of dynamic stress and strain of pouring asphalt concrete material complieswith hyperbolic backbone curve. The influence of different confining pressure and the principal stress ratio ondynamic strength, dynamic modulus and damping ratio is larger than the frequency. When asphalt contentincreased from9.0%to11.0%, the dynamic elastic modulus reduces about20%.(2) The improvement of Hardin-Drnevich model and the preparation of dynamic calculation program.According to the test results, the maximum dynamic modulus formula was improved; Using calculated valueof the improved formula compared with the test results. On the basis, Hardin-Drnevich model was improved.Based the finite element software ADINA and the improved Hardin-Drnevich model, Earthquake dynamiccalculating program on the earthrock was compiled. On the basis of the program, using Shen Zhujiang residualdeformation incremental model, It was compiled with the calculation program of the permanent deformationon earthrock dam, the correctness and applicability of the program calculation results were verified byexample. (3) Dynamic calculation and seismic safety evaluation of pouring asphalt concrete core wall dam. Pouringasphalt concrete core wall dam in view of the dam height of66m in Xinjiang respectively were analyzed onthe static and dynamic finite element calculation, using ADINA software and dynamic calculation program.The static and dynamic working characteristics and change rules of the pouring asphalt concrete core wall damwere researched and evaluated on the seismic safety of the core wall dam. The influence law of the coveringlayer of different thickness to the core wall was discussed. The results show that:1） The maximum valuedistribution rule of absolute acceleration of dam body and core wall and displacement increases fromfoundation to crest gradually, and reaches the maximum near the crest. When the core wall asphalt contentincreased from9%to11%, the absolute acceleration of core wall obviously reduced.2） The permanentdeformation of pouring asphalt concrete core wall dam is the most obvious near central. Vertical permanentdeformation occurred near the middle of the core wall top, the maximum deformation is16.8cm, accounts forabout0.25%of the dam height; When the asphalt content increases to11%, core wall maximum verticalpermanent deformation increases to18.7cm. Vertical subsidence deformation of asphalt core wall in theearthquake is larger than the horizontal deformation, earthquake deformation mainly for the seismicsubsidence. Core wall in the top on both sides exist low stress zone, the part is prone to cracking in earthquakedisaster. The transition layer has the potential possibility of the liquefaction, but the main zone concentrated onthe top of the upstream of transitional layer, so it will not bring harm to the core wall dam.3）The thickness ofcovering layer has a greater influence on the absolute acceleration and dynamic displacement of the corewall, and has little influence on the dynamic stress of the core wall.(4) Sensitivity analysis of the constitutive model parameters of pouring asphalt concrete. The pouringasphalt concrete core wall dam in Xinjiang as the research object, the single factor and multiple factor analysismethod respectively was used, and the sensitivity of the static and dynamic constitutive model parameters forpouring asphalt concrete was analyzed. In multiple factor analysis method, the range and variance analysismethod was adopted respectively to analyze the sensitivity index, and the sensitivity of pouring asphaltconcrete constitutive model parameters on the static and dynamic simulation results of the core wall wasdiscussed. According to the sensitivity analysis of static and dynamic constitutive model parameters,sensitivity of the parameters on the test index had certain difference for the different test index. Therefore, thesensitivity of the parameters should be comprehensive analyzed and researched, the important test index beingselected according to the specific requirements, based on the parameter sensitivity of the key test index, andboth the sensitivity of the parameters for other test index.