The paper presents an approach for evaluation of the likelihood of damage to the transportation infrastructure in the context of the terrorist attacks on the example of a number of bridges located in Wrocław (Poland). Assuming that there will be only one bridge destroyed in a given area, in order to determine the probability of damage to one of the objects, there was one of multi-criteria optimi-zation methods used, i.e. the method of Analytical Hierarchy Process (AHP). The main advantage of the analysis carried out was that the accepted hierarchy of decision-making options could be easily explained in a scientifi c manner, not only with reference to personal knowledge, experience, and intuition.

Horizontal Directional Drilling (HDD) technology is a highly complex process connected with high risk and uncertainty due the high variability underground strata, often limited access to specialised equipment, dynamic natural environment, technical disruptions, human factor and changes in economic environment that further complicate the gathering of reliable information and data. This work presents a new risk evaluation model tailored for HDD technology, in which failure mode and effect analysis (FMEA) modelling were applied. This paper focuses on 15 human risk factors and 9 equipment risk factors in HDD technology. The proposed approach takes into account not only the probability of the risk factor occurrence, but also its severity and the possibility of detecting faults, which were not clearly separated and analyzed in the previous works. Application of the proposed model shows the relationship between occurrence, severity and detection for the analyzed failures. Moreover, many detection possibilities for the identified failures were presented. The calculated risk priority numbers allowed to rank HDD failures and identify the most critical risks for which one should look for risk treatment possibilities beyond risk cause reduction, such as risk effect reduction, risk transfer, risk elimination or active risk retention.

Overseas mining investment generally faces considerable risk due to a variety of complex risk factors. Therefore, indexes are often based on conditions of uncertainty and cannot be fully quantified. Guided by set pair analysis (SPA) theory, this study constructs a risk evaluation index system based on an analysis of the risk factors of overseas mining investment and determines the weights of factors using entropy weighting methods. In addition, this study constructs an identity-discrepancycontrary risk assessment model based on the 5-element connection number. Both the certainty and uncertainty of the various risks are treated uniformly in this model and it is possible to mathematically describe and quantitatively express complex system decisions to evaluate projects. Overseas mining investment risk and its changing trends are synthetically evaluated by calculating the adjacent connection number and analyzing the set pair potential. Using an actual overseas mining investment project as an example, the risk of overseas mining investment can be separated into five categories according to the risk field, and then the evaluation model is quantified and specific risk assessment results are obtained. Compared to the field investigation, the practicability and effectiveness of the evaluation method are illustrated. This new model combines static and dynamic factors and qualitative and quantitative information, which improves the reliability and accuracy of risk evaluation. Furthermore, this evaluation method can also be applied to other similar evaluations and has a certain scalability.

Horizontal Directional Drilling (HDD) is a very complex technology. Although the installation of pipelines by means of this technology is often successful, examples of unsuccessful projects are also known. Due to the complexity of the technology, with the interaction of multiple processes, risks related to uncertainties in these processes play important role. These risks are related to the variability of underground strata, changing natural environment, changes in economic environment, as well as limitations of the equipment, technical disruptions and human factors. This paper describes the risk evaluation results of the FMEA and a Pareto– Lorenz analysis for 14 external risk factors (8 natural or environmental risk factors as well as 6 economic risk factors) in HDD technology. In the proposed approach not only the probability of the external risk factor occurrence was considered, but also its consequences and the ability to detect faults, which were not plainly separated and taken into account in the literature so far. Such an approach has shown the relationship between occurrence, severity and detection for the analysed external failures. Moreover, 40 detection possibilities for the external risks in HDD technology were identified. The calculated risk priority numbers enabled ranking HDD external failures and identified the most critical risks for which the suggested detection options were unsatisfactory and insufficient, and therefore other types of risk response actions need to be explored.