Vibration Control Of Over-track High-rise Building Considering Base Isolation

With the vigorous development of domestic economy and the increasing shortage of urban land resources,the subway has become an important means to alleviate the traffic pressure in major cities because of its large traffic volume,good timeliness,convenience and safety.Although the subway has brought convenience to people’s life and work,the environmental vibration caused by the subway operation can not be underestimated.In recent years,there are more and more complaints about traffic noise and environmental vibration,which has become a major problem hindering the development of people’s livelihood.Taking a super high-rise120 m building of a subway superstructure project as the research object,through the field measurement scheme,this paper explores the vibration reduction effect of pile foundation wrapped with flexible materials,analyzes the measured data,and summarizes the vibration propagation law of subway operation.Then,the reduction effect of pile length and vibration control layer in the superstructure on the vertical vibration of each floor is explored by means of scale model percussion test.The influence of pile foundation outsourcing material on superstructure is verified by finite element simulation.The main contents of this paper are as follows:(1)According to the particularity of the subway upper cover project,the vibration reduction measures of pile foundation wrapped with rubber layer are innovatively designed.The vibration reduction measures of the outer rubber layer of the pile foundation are explained in detail,the testing instruments are listed,and the detailed field measurement scheme is prepared.At the same time,considering the detection of measuring points at different depths inside the pile,the waterproof magnetic acceleration sensor is experimentally assembled to better work stably in the harsh environment under the pile and closely adsorb with the inner wall of the metal pipe,so as to make the detection data accurate and stable and facilitate the induction of data in the later analysis.(2)Refer to the selected vibration detection specification,and process and optimize the field measured data.The measuring points are divided into pile head and different depths under the pile,and the vibration reduction effect of vibration reduction measures is evaluated from different angles such as time domain,frequency domain,frequency division vibration level and Z vibration level,so as to summarize the propagation characteristics of subway vibration environment,and enrich the subway vibration excitation library at the same time.(3)Taking a super high-rise project in Guangzhou as the research background,aiming at a super high-rise structure with laminated rubber bearing as vibration control device and a subway upper cover with long pile foundation,a scale model knock test with a similarity ratio of 1 / 30 is carried out to study the vertical and horizontal dynamic characteristics and dynamic response of the scale model with or without vibration control device and pile length effect,Study the attenuation effect of various vibration control measures on similar subway excitation.(4)By establishing the finite element analysis model of the vibration and secondary radiation noise of the buildings overlying the subway tunnel,setting the calculation conditions of the actual situation,calculating the corresponding results,analyzing the environmental impact of the vibration and secondary radiation noise of the proposed project,and further comparing it with the limit value required by the specification,so as to scientifically evaluate the effect of vibration reduction measures.