1. International conference on Remote sensing,environment and transportation engineering, p.p. 6003-6005, June 2011

2. Abstract Introduction Weights of main factors and sub-factors Evaluation matrices and result

3. A fuzzy comprehensive evaluation model is established to evaluate the holistic risk level of an extra-long tunnel in north China. In the risk evaluation process of the highway tunnel, the recognized risk factors are categorized into two hierarchies, the first hierarchy comprises seven main factors, while each main factor can be further decomposed into one to six sub-factors (second-hierarchy factors).

4. Uncertainty is ubiquitous in all kinds of human activities. In the construction phase of highway tunnels, uncertainties in geological conditions, excavation process and other influential factors often result in disastrous accidents that render life and asset losses. How to evaluate and minimize the impact of construction risks of highway tunnels have attracted much concern of practitioners. it seems to be widely accepted that a risk is a measure of the potential inability to achieve a goal or target within defined safety, cost, schedule, and technical constraints. A risk has two components: the likelihood of failing to achieve a particular outcome, and the consequence of failing to achieve that outcome[1]. A risk is a future event and can often be managed proactively

5. Fuzzy comprehensive evaluation method is widely used for decision making in many areas[2-5]. It’s suitable for multifactor decision system. Since the influential factors of tunnel construction is numerous, and many of them are unclear, a fuzzy comprehensive evaluation method is deployed to work out the holistic constructional risk level.

6. The identification of risks resulting from design and construction is an essential task early in a project. In order to better describe the risk level of the tunnel, a multi- disciplinary, technically and practically experienced group of experts from university professors, experienced tunnel engineers of construction enterprises and administrators of tunnels in operation, are organized to identify the hazard that may encounter in the construction