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The purpose of this paper is to propose a gauge for the convergence of the deterministic particle swarm optimization (PSO) algorithm to obtain an optimum upper bound for PSO algorithm and also developing a precise equation for predicting the rock fragmentation, as important aims in surface mines.

In this study, a database including 80 sets of data was collected from 80 blasting events in Shur river dam region, in Iran. The values of maximum charge per delay (W), burden (B), spacing (S), stemming (ST), powder factor (PF), rock mass rating (RMR) and D80, as a standard for evaluating the fragmentation, were measured. To check the performance of the proposed PSO models, artificial neural network was also developed. Accuracy of the developed models was evaluated using several statistical evaluation criteria, such as variance account for, R-square (R²) and root mean square error.

Finding the upper bounds for the difference between the position and the best position of particles in PSO algorithm and also developing a precise equation for predicting the rock fragmentation, as important aims in surface mines.

For the first time, the convergence of the deterministic PSO is studied in this study without using the stagnation or the weak chaotic assumption. The authors also studied application of PSO inpredicting rock fragmentation.

Conventional rock blasting promotes many negative environmental impacts including ground vibration, flying rock, air blast, and the emission of noise, dust and gases. An unconventional alternative process is the application of electrohydraulic principles. Electrohydraulic blasting is able to create a state of fracturing and rupture in the rock, almost instantly. A high current impulse generator produces the energy, without the above environmental impacts caused by conventional explosives. It is particularly suitable for application in urban areas. The paper describes laboratory experiments, theoretical analysis, consideration of the geomechanical criteria of rock failure and analysis of the electrical parameters of impulse generators related to rock fragmentation. The laboratory experiments included geomechanical and electrohydraulic tests on limestone samples from 50kg up to 150kg. The test results show satisfactory efficiency and energy losses.

Despite the many advantages this type of equipment offers, there are still some major drawbacks. Linear cutting machine (LCM) cannot accurately simulate the true rock-cutting process as 1. it does not account for the circular path along which tunnel boring machine (TBM) disk cutters cut the tunnel face, 2. it does not accurately model the position of a disk cutter on the cutterhead, 3. it cannot perfectly replicate the rotational speed of a TBM. To enhance the knowledge of these issues and in order to mimic the real rock-cutting process, a new lab testing equipment was developed by Hyundai Engineering and Construction.

A new testing machine called rotary cutting machine (RCM) is designed to simulate the excavation process of hard-rock TBMs and includes features such as TBM cutterhead, RPM simulation, constant normal force mode and constant penetration rate mode. Two sets of tests were conducted on Hwandeung granite using different disk cutter sizes to analyze the cutting forces in various excavation modes. The results are analyzed using statistical analysis and dimensional analysis. A new model is generated using dimensional analysis, and its results are compared against the results of actual cases.

The effectiveness of the new RCM test was demonstrated in its ability to apply various modes of excavation. Initial analysis of chip size revealed that the thickness of the chips is largely dependent on the cutter spacing. Tests with varying RPM showed that an increase in RPM results in an increase in the normal force and rolling force. The cutting coefficient (CC) demonstrated a linear correlation with penetration. The optimal specific energy is achieved at an S/p ratio of around 15. However, a slightly lower S/p ratio can also be used in the design if the cutter specifications permit. A dimensional analysis was utilized to develop a new RCM model based on the results from approximately 1200 tests. The model's applicability was demonstrated through a comparison of TBM penetration data from 26 tunnel projects globally. Results indicated that the predicted penetration rates by the RCM test model were in good agreement with actual rates for the majority of cases. However, further investigation is necessary for softer rock types, which will be conducted in the future using concrete blocks.

The originality of the research lies in the development of Hyundai Engineering and Construction’s advanced full-scale laboratory rotary cutting machine (RCM), which accurately replicates the excavation process of hard-rock tunnel boring machines (TBMs). The study provides valuable insights into cutting forces, chip size, specific energy, RPM and excavation modes, enhancing understanding and decision-making in hard-rock excavation processes. The research also presents a new RCM model validated against TBM penetration data, demonstrating its practical applicability and predictive accuracy.

Control of the rock motion associated with blasting can have significant economic benefits. For example, surface coal mining can be made more efficient if the overburden material can be cast further with explosives, leaving less work for mechanical equipment. The final muck pile shape in every type of surface and underground blasting is controlled by the blasting induced motion of the rock. A theoretically sound method of predicting rock motion will be beneficial to understanding the blasting process.

The purpose of this paper is to show how the time frame for the execution of a construction project in Algeria is rarely respected because of organizational problems and uncertainties encountered while the execution is underway.

A case study on the construction of a metro station is used as a pilot project to show the effectiveness of replacing traditional construction processes by more innovative procedures. Concurrent engineering (CE) is applied to optimize the execution time of the underground structure. A numerical simulation is integrated into the construction process in order to update design parameters with real site conditions observed during the construction process.

The results show that the implementation of CE is efficient in reducing the completion time, with an 18 per cent reduction observed in this case study. A cost reduction of 20 per cent on the steel frame support and a total cost reduction of 3 per cent were obtained.

The study demonstrates that the application of CE methods can be quite valuable in large, complex construction projects. Vulgarizing it as “the solution” to adjust time frame delay, control quality and cost, might be an issue for local construction enterprises in Algeria.

Using the concept of CE by overlapping different activities involved in a construction project and making use of simulation tools in the process at different stages of the execution have resulted in modifying the excavation method and hence reducing the completion times.

Blasting is an economical method for rock breakage in open-pit mines. Backbreak is an undesirable phenomenon induced by blasting operations and has several unsuitable effects such as equipment instability and decreased performance of the blasting. Therefore, accurate estimation of backbreak is required for minimizing the environmental problems. The primary purpose of this paper is to propose a novel predictive model for estimating the backbreak at Shur River Dam region, Iran, using particle swarm optimization (PSO).

For this work, a total of 84 blasting events were considered and five effective factors on backbreak including spacing, burden, stemming, rock mass rating and specific charge were measured. To evaluate the accuracy of the proposed PSO model, multiple regression (MR) model was also developed, and the results of two predictive models were compared with actual field data.

Based on two statistical metrics [i.e. coefficient of determination (R²) and root mean square error (RMSE)], it was found that the proposed PSO model (with R² = 0.960 and RMSE = 0.08) can predict backbreak better than MR (with R² = 0.873 and RMSE = 0.14).

The analysis indicated that the specific charge is the most effective parameter on backbreak among all independent parameters used in this study.

This paper describes progress on the development of theoretical models required for studying failure mechanism, crack initiation and growth around the boreholes driven by hydrofracturing processes in Hot Dry Rock (HDR) reservoirs of geothermal energy. Due to the importance of the stress intensity factor concept (K) in Fracture Mechanics, some advanced modeling techniques for accurate and fast determination of K for relevant problems are proposed. Alternative tools to deal with stress intensity factor determination are developed and assessed from the points of view of accuracy and computational cost. We concentrate on residual strength, crack initiation and crack growth as a means to model and understand experimentally observed behaviors. Several modeling methods such as compounding and weight function techniques, and boundary and finite element modeling for stress intensity factor calculation are discussed. Further to reviews of those techniques, work performed included (i) developing alternative solutions to deal with boundary‐to‐boundary interaction when using the compounding technique, (ii) relating the precision of K calculations with the level of precision of the crack opening displacement of a reference solution, in order to assess the precision of weight function technique, (iii) modeling relevant geometries using the finite element method (FEM), (iv) working on the implementation of direct stress intensity factor K determination in the Higher Order Displacement Discontinuity Method (HODDM), and (v) developing tools to deal with residual stress fields around the boundary of the hydraulically pressurized boreholes.

This paper discusses the issues involved in the development of combined finite/discrete element methods; both from a fundamental theoretical viewpoint and some related algorithmic considerations essential for the efficient numerical solution of large scale industrial problems. The finite element representation of the solid region is combined with progressive fracturing, which leads to the formation of discrete elements, which may be composed of one or more deformable finite elements. The applicability of the approach is demonstrated by the solution of a range of examples relevant to various industrial sections.

This study aims to propose a national frame of reference for the accreditation of engineering programs (EPs) in Tunisia. It uses as a benchmark the structure used by the world’s leading accreditation systems such as the Accreditation Board for Engineering and Technology (ABET) and Commission des Titres d’Ingénieur. It provides a comprehensive framework for academic institutions to evaluate the performance of their programs. In addition, it suggests the procedures, steps and timeline for the application process and defines the required documents that should be submitted.

The study analyzes the standards applied by well-established accreditation agencies such as ABET, Commission Titre Ingenieur and European Accredited Engineer, studies the perceptions of academicians who participated in six workshops and uses the results of surveys and interviews to characterize their opinions about accreditation. A sample population of 146 faculty members, experts and policymakers from 23 different higher education institutions in Tunisia, who had participated in the workshops mentioned above, was solicited to participate in the survey. The opinions of 51 respondents who responded to the survey were analyzed. This methodology led to the establishment of a proposed national frame of reference for accreditation of EPs.

Analysis reveals that the Ministry of Higher Education and Scientific Research (MHESR) provides authorization (“habilitation”) to institutions allowing them to offer their educational program. However, it is inaccurate to consider this procedure as accreditation because it is more of a licensure process. In addition, the MHESR grants the “habilitation” to those institutions that successfully apply. The National Authority for Assessment, quality assurance and accreditation Instance Nationale de l’Evaluation, de l’Assurance Qualité et de l’Accréditation (IEAQA) is not involved in this process, which makes the latter’s role trivial.

This frame of reference will help the MHESR to evaluate the EPs based on a comprehensive analysis of well-established accreditation systems, to improve its “habilitation” process by splitting it into two parts as per international practice, namely, licensure and accreditation and to make the existence and role of the IEAQA much clearer.

This study is the foremost study to propose a comprehensive frame of reference for accrediting EPs in Tunisia.

To use distinct element simulation (PFC2D) to investigate the relationships between microparameters and macroproperties of the specimens that are modeled by bonded particles. To determine quantitative relationships between particle level parameters and mechanical properties of the specimens.

A combined theoretical and numerical approach is used to achieve the objectives. First, theoretical formulations are proposed for the relationships between microparameters and macroproperties. Then numerical simulations are conducted to quantify the relationships.

The Young's modulus is mainly determined by particle contact modulus and affected by particle stiffness ratio and slightly affected by particle size. The Poisson's ratio is mainly determined by particle stiffness ratio and slightly affected by particle size. The compressive strength can be scaled by either the bond shear strength or the bond normal strength depending on the ratio of the two quantities.

The quantitative relationships between microparameters and macroproperties for parallel‐bonded PFC2D specimens are empirical in nature. Some modifications may be needed to model a specific material. The effects of the particle distribution and bond strength distribution of a PFC2D specimen are very important aspects that deserve further investigation.

The results will provide guidance for people who use distinct element method, especially the PFC2D, to model brittle materials such as rocks and ceramics.

This paper offers some new quantitative relationships between microparameters and macroproperties of a synthetic specimen created using bonded particle model.