Research On Dynamical Response Characteristic Of Underwater Shield Tunnel Against Impact Force Of Train Derailment

The high speed railway underwater shield tunnel construction has an important role in the construction of China’s high-speed rail backbone nets. In order to assess the safety of underwater shield tunnel under impact force of the high speed train derailment,to improve the reliability of underwater shield tunnel and to create "safety, environmental protection, energy-saving" underwater tunnel project,this paper regard the current China’s high speed railway underwater shield tunnel construction needs as the target, based on Huangpu River underwater tunnel in Shanghai-nantong railway, study on the impact force of train derailmen, the dynamic response and damage performance of segmental lining under the train crash,the key design parameters of anti-collision double linings are carried out.The main works and results are as follows:(1) Based on the finite element theory of impact dynamics and damage theory, variety of concrete damage characteristics and applicable scope are compared; Damage evolution and constitutive equation for concrete segmental lining based on stress-strain relationship recommended by the concrete standard are described and the flow chart of finite element analysis is proposed.(2)A simplified train-rigid wall impact model is conducted for the analysis on train plastic deformation、energy conversion and other mechanical behavior under the impact force of train derailment and time history distribution characteristics of the impact force is carried out. Several factors that influence equivalent impact force, such as train formation,impact velocity, impact angle,are reveled.At the same time,simplified of formulas of equivalent impact are put forward.(3)Dynamic response of single segment lining and double lining shield tunnel that caused by the same impact force.such as stress, deformation, velocity, acceleration and damage factor,are compared.This is conducted for analysis on the protective effect of secondary lining under impact force of train derailment;By applying different impact force,analysis of the relationship between dynamic response of segmental lining with impact velocity and impact angle.(4)The influence of weaken effects in segmental lining caused by secondary lining strength, thickness and other key design parameters of anti-collision double linings are carried out and the design principles of double linings under impact force is made.