Large-scale Triaxial Dynamic Testing Based On The Macadam Bed Of Immersed Tube Tunnel Of Hong Kong-Zhuhai-Macao Bridge

With the construction of Guangdong-Hong Kong-Macao Greater Bay Area,the Hong Kong-Zhuhai-Macao Bridge is playing an important role as a economic and communications hub.Until now,the researches are mainly about the static characteristics of the rubble cushion of the Hong Kong-Zhuhai-Macao Bridge subsea immersed tube tunnel,but few people have studied the dynamic characteristics of it.Nowadays,with the development of immersed tunnel,it is necessary for us to study the rule of changes of dynamic modulus and damping ratio of broken stone handcore for structural dybamic design and analysis.Base on actual working conditions of rubble cushion of Hong Kong-Zhuhai-Macao Bridge immersed tube tunnel,the paper acquires the satisfactory and reasonable results by using large dynamic and dynamic triaxial instrument to measure the dynamic modulus and damping ratio of crushed stone under different confining pressure,relative density and silt content and the sample grading scale.The satisfactory and reasonable results can provide reference for the security maintance of the Hong kong-Zhuhai-Macao Bridge subsea immersed tunnel and the seismic design of the similar projects.The main contents and achievements are listed as follows:?1?The paper summarizes the variation rule of hysteretic loop of excavated samples under dynamic forward cyclic loading.?2?The influence of the dynamic modulus and damping ratio of the crushed stone under different confining pressure,relative density and silt content is analyzed.?3?By fitting 1/E_d-?_dand E_d/E_max-?_d curves,it is found that Hardin-Drnevich model is suitable for describing the dynamic constitutive relationship of soil and the corresponding model parameters are given.?4?Based on the experimental results,the paper acquires the maximum dynamic elastic modulus and maximum damping ratio of the soil sample and analyzes the rule of changes of the maximum dynamic elastic modulus under different confining pressure,relative density and silt content.?5?By using small dynamic and static triaxial instrument to analyze the dynamic properties of silty clay,the paper shows that mechanical property of rubble with silt is depending on the rubble skeleton.