With the increasing expansion of the technology for the production of high- tech military equipment, the need to build STRUCTURES with acceptable resistance against explosion in vital centers increasingly felt. These STRUCTURES as the facilities in times of peace and in times of war and natural disasters are contributing to saving lives. Due to the lack and limitation of experimental data for explosion problems, numerical modeling based on finite element method can help in designing and estimating the loads exerted on STRUCTURES. In this reseARCh, the effects of sacrificial RC slab on the performance of UNDERGROUND ARChed shape RC STRUCTURES with practical details under explosion load were studied. Ls-Dyna finite element software was used to solve the problem and optimized concrete ARChes under different levels of explosives were investigated. Results show that, if a sacrificial RC slab is placed on the crown of the study structure, no damage will occur in structure and structural damages will be concentrated in RC slab. However these damages will be increased with increasing of the explosives. On the other hand, sacrificial slab distributes the blast waves at a higher level of soil which in turn shield the structure against explosion. Consequently, the safety of the structure in terms of performance against blast loading will be increased significantly.

The necessity of designing safe STRUCTURES to withstand an air strike on a ground surface is obvious. In order to meet this goal, the blast characteristics and propagation of intense wave caused by it in discontinues rock media is considered. After selecting a dynamic pulse caused by an airborne bomb, with a specific weight and penetration on the ground surface and calculation of the resulted crater, it is applied, in a radial shape, on the crater surface. Thereby the wave propagation and its damping in a discontinum media is investigated. The rock mass and propagation of dynamic wave in it is modeled using UDEC software. The results show that with increase in the depth of structure, its instability decreases against the blast caused by a bomb with specific weight and penetration. The existence of effective discontinuity also decreases this possibility. Under the same conditions the possibility of the structure stability increases if the slope angle against the line drawn to the center of the blast is about 60 degrees.

Regarding the application of testing and analysis of bone fractures in both medical and engineering fields, finding proper specimens for measuring fracture properties is important. In this study, the experimental and numerical fracture analyses of bovine cortical bone were performed for 4 anatomical regions using ARC-SHAPED specimens. The tensile fracture tests for ARC-SHAPED specimens were performed at ambient temperature. In practice, the stress intensity factor was calculated using standard analytical formula for ARC-SHAPED specimens and also the related finite element (FE) models. In order to validate the FE models, the stress and strain analyses results were compared with the results obtained from digital image correlation (DIC) method. The very good agreement between these results was indicative of the accuracy of FE analyses. There were also good correlations between the initiation and propagation of crack from both experimental and FE results and the measured fracture toughness values were in good agreement with those reported in the literature. The results of this study showed that the analytical stress intensity expressions can give accurate results for the ARC-SHAPED specimens excised from posterior and anterior regions. However, for the medial and lateral regions only the FE models can provide the required accuracy.

This paper presents a description of the equipment, testing procedure, and methodology to obtain ground mechanical parameters. The p-y curves for laterally loaded piles are developed. Methods for the development of p-y curves from pressure meter and dilatometer (DMT) test are described. P-y curves are used in the analysis to represent lateral soil-pile interaction. The pressure meter offers an almost ideal in-situ modeling tool for determining directly the p-y curves for the design of deep foundations. As the pressure meter can be driven into the soil, the results can be used to model a displacement pile. DMT tests were performed for comparisons with PPMT tests. Correlations were developed between the PPMT and DMT results, indicating a consistency in soil parameters values. Comparisons between PPMT and DMT p-y curves were developed based on the ultimate soil resistance, the slope of the initial portion of the curves, and the shape of the curves. The initial slope shows a good agreement between PPMT and DMT results. The predicted DMT and PPMT ultimate loads are not similar, while the predicted PPMT and DMT deflections within the elastic range are identical.

Geophysical methods are used as locating tools and reconnaissance methods. Gravity method is used to locate UNDERGROUND STRUCTURES and cavities using density contrast. In this paper, methods of airborne gravimetry and airborne gravity, gradiometry, corrections and their modern instruments have been presented. In order to evaluate the accuracy and efficiency of these methods, a developed program have been used. Artificial data of an UNDERGROUND structure have been provided by forward modeling for earth surface at different altitudes and then noise were added to data. Finally the results of the simulation and the accuracy of the presented instruments for different altitudes have been compared. In conclusion effective solutions to mitigate the probable detection of buried STRUCTURES and the improvement of camouflage processes against airborne reconnaissance are provided.

In seismic design of engineering STRUCTURES, usually bedrock acceleration-displacement response spectra are within hand. The crucial issue in seismic design of UNDERGROUND STRUCTURES is the serious need for the geotechnical logs to be used in numerical simulations. However, large dimensions of typical sub-surface STRUCTURES like tunnels, subways and sewage water transporting routes, require considerable logging efforts based on notable budgets. As such STRUCTURES would lay several ten meters under the ground surface, the mentioned efforts and budgets expand with respect to that of required for over ground systems. Hence, any approximate estimation on critical bedrock depth can help to draw reasonable engineering design judgments. Providing such information, regardless of precise log information, guide the designer to implement conservative assumptions and reach upper bound estimations on seismic demands. To approach this goal, here, an investigation is conducted to find such critical depth parametrically. The STRUCTURES are considered as box SHAPED long embedded systems for which 2D rectangular cross sections are studied linearly and a simple procedure for fast and conservative seismic design is proposed. To this end, the article constitutes of two parts. At first, the approximate relation between maximum bedrock displacement (DB) and maximum internal drift of the soil layer over the bedrock (DL) is explored. It is notable that in UNDERGROUND soil-structure interaction, the soil deformation field surrounds the structure and through an interaction procedure, both soil and structure converge to an equilibrium state. So, maximum internal deformation of the soil layer, in which the structure is embedded, plays an important role in seismic demands of subsurface struc tures. In this part, a set of 20 real bedrock records is utilized to reach the approximate DB-DL relation through a linear wellknown closed form equation for single layer transfer function. The bedrock histories were all selected from the sites with shear wave velocity, Vs, over 700 m/s. The results of this part show that the average value of DL, for the selected set of records, is approximately close to the value of DB. In the second part, various Finite Element (FE) models were developed in ABAQUS software including different STRUCTURES. Then, the resulted DL from previous step was applied to the boundaries of FE models, in first-mode-shape of each layer. It is supposed that the total layer deformation comes from its first mode shape. Next, the uppermost flexural, shear and axial strains are tabulated and sketched against the parameter H/Vs, where H is the soil layer depth. This process was repeated for STRUCTURES with different values of flexibility ratio, FR, and aspect ratio, AS. The effect of h/H ratio is also reviewed where h is the structure vertical dimension. The depth of the structure from ground surface is set to a constant value and just a single layer over the bedrock is taken into account. The trends of strain demands and critical layer depths are the explored and discussed. It is shown that, as the distant of the structure and the bedrock diminishes, the strain demands increase. This happens as the maximum gradient of soil deformation occurs near the bedrock surface. This makes clear that, in the absence of enough information on soil layers, it is suggested that the minimum stratum laye5r depth to be considered for a conservative analysis. Such depth, which can be assumed as the overburden depth plus structural vertical height, is expected to produce the upper most seismic demands for preliminary design of UNDERGROUND STRUCTURES. It should be noted that this reseARCh is based on linear analysis and complementary investigations, considering different types of nonlinearities, are required to reach more precise conclusions with more reasonable safety factors.

UNDERGROUND excavation in hydroelectric power plants is mostly done by drilling & blasting method. Vibration, which is an undesirable result of blasting, has been always focused by reseARChers. Sensitivity of the nearby structure and nearby operations dictates the level of control on vibration. This reseARCh aims to study applicability of artificial neural networks for prediction of blast vibration in three different projects. These projects include Karun III, Masjed Soleiman and Siahbishe hydroelectric power plant. Empirical equations have been also applied to the data from these sites. It was found that Langefors-kihlstrom model can predict blast vibration in Karun III and Masjed Soliman Sites better than other models. However, Predications of this model is poor in Siahbisheh Site. From the other hand, artificial neural networks showed considerable advantages in vibration predication at all sites, when compared with different Empirical models. The correlation coefficient (R2), for Empirical models, was from 0.45 to 0.8 at different sites. For artificial neural networks models, this coefficient was 0.94 for two sites and 0.83 for the third one. It was concluded that neural networks can be accurately employed for predication of blast vibration. This capability can be further enhanced if large amount of date are available.

Most of UNDERGROUND STRUCTURES are designed and built to withstand the effects of precision penetrating weapons and heavy bombs in the soil. Usually the depth of the STRUCTURES is high and there is no possibility of missiles to the main structure. Accordingly, the design of these STRUCTURES is performed for blast loads. The explosion phenomenon is a type of high strain rate problem that requires dynamic analysis to solve. Also, due to the interaction between UNDERGROUND STRUCTURES and soil, the analysis of these STRUCTURES is affected by any type of nonlinear analysis. Thus, the analysis of UNDERGROUND STRUCTURES in simulations affected by the explosion is a high strain rate problem that requires nonlinear dynamic analysis. There are two implicit and explicit solutions to dynamic analysis that, given the explosion problems, their analysis is explicitly integral. The loading of UNDERGROUND STRUCTURES is often based on the relationships obtained from theoretical and experimental reseARCh. Currently, the most important reference for explosive loading in the field of UNDERGROUND STRUCTURES is the US code (TM5-855-1) provided by the US army. The numerical simulation methods have recently been widely used as a novel method in the calculation of nonlinear dynamic loads. According to the reseARChers, among the explicit software available in AUTODYN software, due to its ability to solve very high strain rate problems, it yields good results from simulation and explosion problem analysis. On the other hand, the explosive loading of UNDERGROUND STRUCTURES is often based on theoretical and empirical reseARCh. In this study, a numerical simulation method was used to analyze and simulate the effect of the surface explosion on the UNDERGROUND structure. Also, all the simulation steps were performed using AUTODYN hydrocode. In order to analyze the loading and response of UNDERGROUND STRUCTURES, the effect of the explosive charge weight and the depth of burial of the structure has been studied and the numerical results have been compared with the relationships presented in reliable US scientific and guidance sources. Finally, suggestions are made to improve the loading of these STRUCTURES. Also, considering the results of the load on the roof of the structure, it was observed that the values of the US code are conservative compared to the other two methods. Therefore, it is recommended not to apply 1. 5 incremental coeficient load to the structure in accordance with this instruction. The numerical simulation results including a comparison of maximum pressure and the velocity values with the values provided in the by code (TM5-855-1) showed that the predicted values for the maximum pressure values larger than of instructions America's Army. The reason for this is that the code assumes that the investigations take place in the full explosion range (mating coefficient f = 1), while in the numerical model under consideration, the explosion is formed at the joint surface of air and soil. Hence the coupling coefficient is equal to (f = 0. 4). In other words, the depth of the explosive charge is almost zero and there is little difference between the results.

Sustainable development is an integral part of the modern world. However, sustainable development is impossible without rational, environmentally and economically efficient use of resources. In the process of construction and operation of UNDERGROUND STRUCTURES (mines, subway stations, subway parking lots, etc.) there are many factors that cannot be taken into account at the design stage. These factors have a negative impact on the durability of use, economic profitability of operation, etc. In this paper, the authors used the theory of system analysis to form and optimize the factors affecting UNDERGROUND STRUCTURES. They identify the relevant regularities and interrelationships. They determine the list of the most important factors based on the peculiarities of a particular object of study. They build a conceptual and then a mathematical model. In the practical part of the study, the authors model the temperature field formed in a horizontal mine. They compared the obtained results with the modeling results presented by others and showed the effectiveness of the proposed methodology. A distinctive feature of this work is the proposed methodology for assessing the factors affecting sustainable development. This methodology is universal and can be applied to assess the sustainable development of any management object.

In this paper, we perform a detailed study of the spectral response of the gold U-SHAPED nano-STRUCTURES for different geometrical parameters and polarizations in order to obtain significant localization factor in the wavelength 1. 55 μ m. The obtained near-field distribution of electric fields reveals that resonances in these nano-STRUCTURES correspond to the even and odd plasmonic modes depending on the geometrical parameters and polarization directions. Considerably large localization factor is obtained for the first odd mode in specific geometrical parameters. Then, this structure is considered to be surrounded by a typical secondorder nonlinear dielectric. The effective susceptibility is calculated for the considered structure, using the nonlinear retrieval method, to demonstrate the enhanced second-harmonic generation quantitatively. In order to represent the applicability of the investigated structure in nano-scale light sources and frequency doublers, its second harmonic generation efficiency is compared with the efficiency of the nonlinear dielectric alone with the same dimensions.