Notice of RetractionRisk analysis of shield tunnel segment failure based on Fuzzy Fault Tree method
Through analyzing and summarizing the types of shield tunnel segment failure and the relevant causes of the accident, Fuzzy Fault Tree Analysis (FTA) was employed to study the failure risk of segment and the Fuzzy Fault Tree system model of segment and segment-related systems were established. The potential failure modes of risk accidents and their influencing factors were discussed through qualitative and quantitative analysis. With its application on practical project, some effective control measures were proposed. This research could be valuable reference for the design, construction and control of shield tunnel segments.
Abrasivity of Soils in TBM Tunnelling
This article focuses on the effect of abrasive ground on TBM tunneling. While rock's effects on TBM tunneling are well known, less work has been done on soil abrasiveness and its impacts on equipment such as cutterheads. The authors describe the different parts of the TBM that can suffer damage and recommend steps to establish regular inspection and maintenance programs for soft ground TBM projects. Some specific cases are cited to illustrate the vulnerability of different TBM components. A bar chart shows different weathered granites and the disc cutter consumption associated with different ground conditioning. The authors recommend a more objective set of measures for soil properties in order to permit TBM projects to be better managed.
What Happened to Suicide Bombings in Israel? Insights from a Terror Stock Model
An analysis of three years of suicide bombing data in Israel reveals an increase in such attacks through March 2002 followed by a steep decline through the end of 2003. The authors propose a terror-stock model that treats the suicide bombing attack rate as a function of the number of terrorists available to plan and execute suicide bombings. The intent of Israeli tactics such as targeted killings and preemptive arrests is to reduce the capacity of terror organizations to commit attacks. When fit to the data, this model suggests that the targeted killing of terror suspects sparks estimated recruitment to the terror stock that increases rather than decreases the rate of suicide bombings. Surprisingly, only the deaths of suspected terrorists, and not Palestinian civilians, are associated with such estimated recruitment. Although Israeli actions have reduced the rate of suicide bombings over time, it is preventive arrests rather than targeted killings that seem more responsible for this outcome.