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Studies of craters produced by explosions above and underneath the ground surface are rarely found in the open technical literature. Most reports are confidential and access is limited to government agencies. Much of the information on explosively formed craters found in the literature is based on experimental data. Numerical studies were very limited until recently. An ablity to predict the anticipated size of crater is crucial to identification of the corresponding damage that might be caused by a given explosive charge, or to assessment of the magnitude of the charge if this is not known. In this paper a non-linear dynamic numerical analysis of the explosion phenomena in clay soils associated with different amounts of TNT explosive charge is performed using the ABAQUS/Explicit computer program. To validate the numerical procedure and material constitutive models used in the present work, a comparison with experimental results is first performed. The results obtained illustrate that the agreement between the numerical and the experimental results is reasonable. A study of the influence of soil density on the crater dimensions is then undertaken. From the numerical results obtained, a new prediction equation is proposed for the crater dimensions as a function of the explosive charge considered. This equation represents the approximation of the numerical results by least squares fitting.

The response of buried concrete structures to the effect of blast loads is of great importance. Various parameters including the depth and weight of explosive charge, soil properties and the relative location of the buried structure to the explosive charge affect the structural performance of buried structures. In this paper, the influence of burial depth of explosive charge is numerically investigated using the new proposed finite element model developed and described in a previous work for the authors. The burial depth of explosive charge is considered to be varied between 0.0 m to 6.0 m. A comparison evaluation is carried out between the study of varying charge depth and the study of varying the burial depth of the structure. This investigation covers the blast wave propagation, structure response and damage analysis for buried reinforced concrete structures. The paper shows that buried explosions result in significant effects on the structure response than the surface explosions with the same conditions.

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Solid waste management is a serious problem worldwide as the amounts of produced wastes are increasing annually. For example, the disposal of waste gypsum plasterboard, used as dry walling across the world, represents a serious environmental issue. Therefore, this study examines the potential for reusing plasterboard wastes as a stabiliser material for earthwork projects, especially for organic soft clay soil. Recycled plaster, mixed with cement or lime at different ratios was used as a stabiliser for tested soil. Atterberg limits, scanning electron microscopy, x-ray diffraction, compressive strength, and secant moduli tests were conducted to evaluate the improvement in stabilised soil properties. The results indicate that the inclusion of plaster–cement (B–C) or plaster–lime (B–L) admixtures improved the geomechanical properties of the stabilised soil, with higher admixture concentrations leading to greater improvement. Moreover, the soil specimens stabilised using the B–L admixture exhibited a higher strength gain rate and reduction in plasticity index and water content than those stabilised by the B–C admixture. The development of cementation compounds in a stabilised soil matrix has a considerable effect on permanent strength enhancement. It is concluded that the proposed stabilising technique can be valuable for both waste management and construction industries.

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Using different types of reinforcing layers such, metallic (non-extensible -steel) and nonmetallic (extensible -geosynthetic) to improve the bearing capacity of weak soil is studied. Many researchers have studied the effect of using reinforcing layers to predict the improvement occurred in weak soil under static load [1]- [5]. Most of these studies are on strip or circular footing. But, square footing is a common shape that used in foundations systems; however, some researchers studied it [6]- [11]. The behaviour of strip footing resting on geosynthetic reinforced sand is studied under cyclic loading [12]. ABSTRACTBearing capacity of soil is considered an important parameter at which the soil can resist loads above it. Different ways are used to improve the bearing capacity of weak soils. One of the used techniques is the soil reinforcing technique. In this study, the results of numerical simulations on square footings resting on geosynthetic reinforced sand are presented. In order to predict the improvement in the bearing capacity resulting from the usage of the reinforcing layers in the sand, finite element analysis package ANSYS is used. Nonlinear Drucker-Prager's model is used as material model to simulate the soil and Linear Isotropic model is used as material models to simulate the reinforcing layers and the footing respectively. SOLID45 element is used as element type to simulate the soil and the footing and Link8 is used as element type to simulate the reinforcing layers. Numerical model of 150mm x 150mm x 25mm is used to simulate the square footing and model of 900mm x 900mm x 600mm is used to simulate the soil. Under the effect of both static and dynamic loading two main effective parameters are discussed in this study. The investigated parameters are the number of the reinforcing layers and the depth of the reinforced zone which includes the variation of spacing between the reinforcing layers. The bearing capacity improvement investigation is analyzed.

This paper examines the performance of composite plates with PVC foam cores and T700/epoxy composites face sheets, and steel plate have the same areal mass when subjected to Underwater Explosion (UNDEX). The objective of this study is to evaluate the dynamic response of those plates. A non-linear dynamic numerical analysis of the underwater explosion phenomena is performed using the ABAQUS/Explicit finite element code, which provides an important analysis tool that can help engineers and designers to design and construct better structures to resist shock loads. The temporal evolutions of plate deflection and central deflection histories were obtained. Further investigations have been performed to study the behavior of failure. The results indicate that the behavior of composite plate with PVC foam core to resist shock loads resulting from an UNDEX is better than steel plate, and the core thickness has a great effect on the plate`s response. The obtained numerical results can help to suggest design guidelines of floating structures to enhance resistance to underwater shock damage, since explosive tests are costly and dangerous.