Study On The Influence Of Road Traffic Vibration On Kaifeng Ancient City Wall

Road traffic vibration is micro-vibration.Although the energy generated in a short time is small,under the long-term action,road traffic vibration will lead to the dynamic response of adjacent buildings,wall structure cracking,loosening,foundation subsidence,damage accumulation and strength reduction.The ancient city wall of Kaifeng is close to the road and it is passed through by vehicles continuously every day.Under the increasingly heavy road traffic vibration,the structural performance of the wall will be greatly affected and its safety will be seriously threatened.In this paper,the ancient city wall of Jinyao gate and Shuncheng road in Kaifeng city is taken as the main research object.The dynamic response of the ancient city wall under the road traffic vibration is analyzed by the method of the laboratory test,on-site monitoring test and numerical simulation.The main research contents are as follows:(1)Physical and Mechanical properties of wall soil and wall bricks were analysed.Density,particle screening,liquid plastic-limited,compaction,triaxial test and springback test of wall soil and wall bricks were carried out,the calculation parameters of relevant materials were determined.(2)The traffic volumes were investigated.The vehicle load model and parameters were obtained by analyzing the traffic flow in each time period,and the random excitation under various conditions were summarized.(3)The in-situ dynamic test was carried out.The vibration signal and attenuation law of each monitoring point of the ancient city wall in different directions under road traffic vibration were obtained by monitoring the ancient city wall of Jinyao gate and Shuncheng road in Kaifeng.(4)The vibration response law of Kaifeng ancient city wall is measured.The vibration signals by monitoring were analyzed in the time domain and frequency domain,and the amplitude of vibration acceleration and velocity was determined as the vibration evaluation quantity during the typical time period.The vibration response law and frequency distribution of the wall were obtained under the road traffic.(5)The response law of simulated vibration of Kaifeng ancient city wall were analysed.The road-foundation soil-Jinyao gate ancient wall model and road-foundation soil-Shuncheng road ancient wall model were established to simulate the physical model of Kaifeng ancient wall under the road traffic vibration.The dynamic response and attenuation law of Kaifeng ancient wall under different working conditions were obtained.The results of the experimental and simulation are compared and the protection measures of the ancient city wall were put forward.