The shear strength of an unsaturated soil is controlled by two variables; net stress and suction. The conventional triaxial machine which is used for obtaining the shear strength of saturated soils cannot be used for unsaturated soil conditions due to weakness in suction control during the consolidation and shearing stages. In the view of this, the standard triaxial apparatus needs to modify and develop for unsaturated conditions. The main aim of this paper is devoted to give a description of current methods and techniques using triaxial apparatus for obtaining data to interpret the accurate shear strength behavior of unsaturated soils. In additional some of the key aspects related to air diffusion and volume change measurement are highlighted.
The conventional theories of soil mechanics use linear envelope to derive shear strength; this however, leads to an overestimation of the factor of safety in the examination of slopes. Therefore, the incorporation of methods that acknowledge the existence of non-linear characteristics of shear strength is necessary in the analysis of slopes specifically. This is due to the substantial influence of non-linear shear strength behavior on the slope failure mechanism when they are at low stress levels. In this paper, the nonlinearity of shear strength for grade VI granitic residual soil is studied. “Non-Axis Translation Consolidated Drained Triaxial” tests were performed at various ranges of net stress and suction. Thereafter, to characterize shear strength behavior, shear strength parameters were derived. The soil-water characteristic curve was plotted after conducting “Pressure Plate Extractor” test at a series of suction. The result substantiated the non-linearity of shear strength for granitic residual soil based on net stress and suction.
The developments in communications technology bring changes in human life, and the positive aspects of these technological innovations make life more accessible. However, the use of communications technology at a certain frequency will produce radiation that could negatively affect human health. Thus, various studies have been performed to obtain a corresponding material to reduce the levels of exposure to the pollution of the electromagnetic wave signal. This study aims to build anti-microwave brick walls and analyze the absorption performance of the anti-microwave brick walls by using carbon biomass as an absorbing material. Carbon biomass is a physically defined product obtained in a highly controlled process to produce specifically engineered aggregates of carbon particles and in this project, carbon biomass was used as an absorbing material in brick production. The absorption performance of the anti-microwave brick walls was measured by using Naval Research Laboratory (NRL) arch free-space method, and the frequency range of 1GHz to 12GHz is used. The result shows that brick containing the highest percentage of carbon biomass produces the best absorption performance at a high-frequency band (4-8GHz), with maximum absorption of -29.53dB.
Slope stability involves developing a terrain slope profile and determining the geometry of the failure surface to compute the slope factor of safety. Terrain capture and reconstruction traditionally has been expensive, time consuming and manpower intensive. This innovative method utilizing unmanned aerial system technology alongside the advancement in graphics processing can be proven as more effective and cost efficient. This research aims to develop a method to forecast the occurrence of landslide by utilizing drone technology. The objectives are to obtain data on terrain slope, create 3D model of the land, then perform analysis on the slope stability. Drone technology equipped with high accuracy GPS system captures high resolution aerial images of a land area for mapping. The data obtained is uploaded into computer software to generate the 3D model of the land. Then, the critical details such as contours or the elevations can be extracted. This information is transferred into an alternative software such as GeoStudio to analyze the stability of slope. Thus, the results can be used to predict the level of safety of the terrain slope and taken for further safety measures involving the particular area.
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