Urban Shallow Tunneling Method Of Risk Identification And Control Technology

Tunnel and underground work undertaken by shallow tunneling method in urban weak soil layer can result in great ground subsidence and can endanger surroundings such as roads,bridges,and pipelines. Moreover, the Shallow Tunneling Method (STM) has so many construction procedures with frequent mechanics transformation that application of the method in cities may generate greater risks. Therefore it's quite necessary to do in-depth research on the STM in terms of risk identification, risk evaluation,risk assessment and risk control. With research into the application of risk management to the Entrance and Exit Program of Loop Load 2nd of Beijing Financial Street, this paper aims at safeguarding the success and safety of the construction works.With regard to the risk management system of tunnel and underground work using STM, the paper will address the following aspects:1. Analyzing the mechanism and source of risk in tunnel and underground work with shallow tunneling method.2. Categorizing types of risk and sets up the risk evaluation index system using breakdown structure method of risk factors and risk sources with combination of research methods of experts and characteristics of risks involved in STM and tunnel construction.3. Establishing the Degree of membership matrix of risk probability P and the Degree of membership matrix of loss C according to the subjective assessment of experts, and establishing the risk evaluation matrix on the basis of R=P×C .4. To determine the index of weighted set of risks with two-two Comparison Matrix established by using the method of analytic hierarchy process.5. Making primary fuzzy comprehensive evaluation and secondary fuzzy comprehensive evaluation of identified risks at all levels.6. Based on results of secondary fuzzy comprehensive evaluation, numerically simulating major risk factors during the construction period with fast finite difference software FLAC3D,and studying temporal and spatial effects of risks so as to provide a theoretical framework for risk control measures. 7. Putting forward the risk control measures of Entrance and Exit Program of Loop Load 2nd of Beijing Financial Street,predicting the effect of risk control measures,8. Developing risk-assessment software of shallow tunneling method with the help of visual programming language vb6.0 so as to utilize computers in risk assessing.