In order to protect coastal structures from the damage due to impact force of tsunami, a new concept of using waste tires behind such structures is introduced in this paper. A physical model for tsunami impact force simulation was developed to evaluate the reduction effect of tsunami impact force by the tire structures. From aesthetic point of view, cultivation of suitable plants inside the tires is also proposed. Field tests on planting trees that can grow in saline soil conditions were performed to see whether such structure can preserve the greenery of the area.

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This paper present the effect of a new invention of scrap tyre mat (8R-Mat) inclusion on the bearing capacity, settlement and stability of a rigid strip footing constructed on a riverbank slope. An 8R-Mat reinforced riverbank will be modelled and analyzed for the effect of inclusion of 8R-Mat by Finite Element Method (FEM) using Plaxis. 8R-Mat is a new invention of reinforcing mat fabricated from scrap tyres. It can be served as reinforcement, filtration, separation, drainage and barrier at the same time. A broad series of conditions, including unreinforced cases, was analyzed by varying parameters such as angle of slope, number of 8R-Mat layers, length of 8R-Mat and water level of river using Plaxis. The results were then analyzed to find both qualitative and quantitative relationships between the bearing capacity, settlement and stability with the parameters. The results show that the bearing capacity and settlement of rigid strip footing can be intensively improved by the inclusion of 8R-Mat in the ground, and the magnitude of bearing capacity and settlement depend greatly on the angle of slope. It is also shown that the bearing capacity and settlement of the rigid footing can be considerably improved depend on the configuration in the ground. Increase of water level generally reduces the bearing capacity and safety factor but increase settlement of the rigid footing. Improvement of safety factor of the riverbank is considered negligible with the inclusion of 8R-Mat in the slope.

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Erosion in the coastal area of Bangladesh is a big point of concern. The present study was conducted to find out the protective measure from coastal erosion in Bangladesh as well as evaluate the prospects of the formation of artificial beachrock. This study was conducted based on literature survey of related works. In the coast of Bangladesh, average recession through erosion will occur 0.87m due to per 1cm sea level rise. Beachrock as well as artificial beachrocks have the potentiality to prevent such coastal erosion. Beachrock is a type of sedimentary deposit that generally occurs on the tropical and subtropical beaches as a result of intertidal lithification of loose beach sands and gravels by carbonate cementation. Beachrock in the world differs by their chemical composition but it composed mainly of CaCO₃, SiO₂ and Al₂O₃. Usually, beachrocks are formed by the cementation of CaCO₃ precipitation with the influence of seawater and/or seawater evaporation as well as surface microorganisms. From the knowledge of natural beachrock formation as well as sand properties, in the future, it may possible to manufacture artificial beachrocks similar to beachrocks for erosion control purposes in Bangladesh.

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This paper focuses the mechanical properties of the deteriorated cement mixed marine clay when immersed in seawater. Series of shear box tests were conducted maintaining the constant volume for the deteriorated cement mixed Ariake clay. The deteriorated specimen was prepared immersing into the artificial seawater simulated in the laboratory for 630 days. Authors compared the change in mechanical properties of the deteriorated specimen with the non-deteriorated cement mixed clay. The deterioration of specimens with intrusion of simulated seawater increases compressibility which is associated entirely with the presence of cement at the beginning of the experiment. The deterioration decreased the shear strength of the cement mixed marine clay. The strength of deteriorated cement mixed marine clay dissolved by calcium is almost equal to that of the remolded Ariake clay.

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Rainfall erosivity considers the rainfall amount and its intensity. This is an important parameter for soil erosion risk assessment under future land use and climate change. Comparisons of all climatic parameters show that rainfall is directly involved in the loss of soil quality during torrential rain. The effect of rainfall erosivity in Penang was considered for two stations, Air Itam and Simpang Ampat. Monthly as well as annual rainfall was obtained from the Department of Drainage and Irrigation, Malaysia for thirty years (1983-2012). Trends analysis of the rainfall data were obtained for each decade that shows trends for mean monthly rainfall. This was conducted using Mann-Kendall trend analysis and Sen's slope tests. Trend analysis shows that there is no significant difference in mean monthly rainfall for the studied period except for Simpang Ampat. The Fournier indexes were used to determine the effect of extreme rainfall events towards soil erosivity. Air Itam recorded 10% cases of very severe impact using Fournier index and 3.33% cases of very high impact using modified Fournier index. The result shows that there is a positive correlation between rainfall trends and soil erosivity.

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In this paper, the erosion and entrainment behavior of debris flow is investigated by three-dimensional finite element analysis based on Coupled Eulerian-Lagrangian (CEL) method. Special attention is given to the strain softening model in capturing the soil strength loss under large strain. The appropriate case studies needed for verifying the three-dimensional (3D) numerical methodology are presented. It is found that the numerical method shows good agreement with the general trend observed by the experimental tests and thus, represents a realistic phenomenon of debris flow. It is found from that a rigorous numerical analysis can provide a potential influence of debris flow and guideline on countermeasures.

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The fracture morphologies of mud pastes show significantly complex patterns in nature. The mud pastes initially have fluid-like properties, but gradually change from “fluid” to porous “solid” in their drying process. The mudcrack phenomena in nature, therefore, is one of the complex physical phenomena of interest in material sciences. However, although it has been considered that mudcracks may be induced by the friction caused by the differences between shrinkage ratios of soil skeletons, the mechanical details remain unknown. In this work, we attempt to develop a novel numerical model based on three dimensional finite element method for mudcrack growth in Bentonite pastes. This model is the first description for mudcrack simulation based on three dimensional solid analysis. In order to validate the proposed model, Hausdorff fractal dimension of the numerical fracture patterns is compared with those of the experiments. As a result, the numerical results showed fracture patterns reasonably, and the fractal dimension of the cracking pattern by numerical simulation was almost consistent with the experimental results.

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