Study On Dynamic Characteristics Of Earth-rock Dam Material

Because of many advantages, such as investment, fast construction and have strong adaptability to a variety of topographic and geologic conditions, earth dam has been widely used in the construction of water conservancy and hydropower. In recent years, the height of the earth dam has a great development and has been achieved from the150m to300m. However, in our country, earth dam located in Southwest canyon area.In these ares,the intensity, frequency of activities of earthquake is high and dynamic parameters of seismic fortification generally higher. Therefore, the earth dam seismic safety is one of the key technical issues which must be addressed in the design.In order to assess the seismic safety of earth dams, it needs to seismic dynamic response analysis and permanent deformation for the earth dam. The basis of these analyzes is the study on the feature of dynamic deformation and permanent deformation.In current engineering practice, the parameters of dynamic deformation and permanent deformation for the material of high earth dam is obtained by the large-scale dynamic triaxial test.but for the small and medium-sized projects not test, the parameters is obtained by engineering experience which is uncertainty.According to the dynamic testing of rock-fill, Shen Zhujiang proposes the formula for residual body strain and residual shear strain. After engineering practice shows that the calculated results have a certain amount of irrationality. In view of this, a number of scholars improved Shen Zhujiang mode. According to organize and analysis a large number of experimental data, This article also improves Shen Zhujiang mode and compares the similarities and differences of each model by face rockfill dam finite element analysis. Finally, to obtain some conclusions this can provide a reference for future research. On the other hand, according to a number of high earth-rock dam dynamic test data, proposed the statistical curve of the relationship between cvr and γd, cdr and yd and including the average curve, double the variance curve and twice the variance curve. And then, to identify the scope of the experimental data points concentrated. These formulas can be used to determine the reasonableness of the dynamic test results and also can be directly used as dynamic parameters of the sensitivity analysis of the dam and the dynamic parameters of the middle-small scale dam project. To study on dynamic characteristics of dam material by the large coarse-grained soil simple shear apparatus which is developed by Dalian university of technology.Preliminary tests for this device showed that the parameters getting by this device accord with the theoretical value and its test accuracy to meet the requirements. The instrument reached a preliminary design goals and can do relevant soil test.The Lateral pressure has a certain impact on the relationship between cvr and yd, cdr and γd.When the greater the lateral pressure, G/Gmax decay slower and curve of damping ratio reduce. Chen Chongmao compiled the dynamic characteristics of the dam material and draws some interested in conclusion. On the basis of Chen Chongmao’s research work, this article further normalized of the variation of the modulus and damping by introduce the reference shear strain which consider the impact of the lateral pressure. As a result, we obtained a higher correlation coefficient statistical curve, and give the mathematical expressions related to curve fitting.