Moisture-dependent resilient modulus of chemically treated subgrade soil

Traffic loads induce cyclic loading under influence of environmental factors, and is affected by the variation of moisture content and suction (s). These parameters are difficult to quantify, and the methods for determination are cumbersome. This paper presents extensive experimental studies used to obtain the resilient modulus-suction (MR-s) relationship of the treated subgrade soil. An optimum design of bentonite‑magnesium-alkalinization (BMA) was used an additive. The cyclic Triaxial frame with ELDYN system was employed to measure MR values and the suction was estimated using the filter paper test. A bimodal soil water characteristic curve (SWCC) was observed for treated soil with unheated BMA additive and pre-treatment at heated (BMAH) conditions due to the presence of cementitious products. The MR-s relationship was also developed for the stabilized soil using a normalized model. Results showed that the BMAH samples had a significant level of improvement of MR at higher suction levels as compared to BMA samples but this behaviour of BMAH didn’t sustain under fully saturated condition. The change in moisture contents under seasonal variation affects the subgrade performance. This study shows the soil additive can effectively improve the mechanical properties of the soil under various moisture contents. The MR for the treated soil can be estimated using the normalized model under the worst-case scenario of a subgrade when the soil is at a fully saturated condition

The comparison of solar irradiance assessment at different terrain in west Malaysia

Solar energy is one of the renewable energies that is emerging in our country's development, in conjunction with the developing green technology effort. Environmental difficulties and the costly price of energy are two of the most concerning aspects of electrical power production. The primary goal of this study is to determine the optimal solar panel angle. The objectives are to achieve the goal to determine the maximum azimuth angle for solar panels in hilly and flat locations in Ampang, Malaysia, as well as to calculate the sun irradiance of solar panels at the chosen location. To maximise the overall output of electrical energy, the tilt angle of the fixed structure solar module was carefully analysed for various locations and periods. Two different locations in Ampang were analysed for observing the maximum input of solar irradiance which were in a hilly area of 3°10'25.1'' N 101°47'28.7'' E and a flat area of 3.1491° N, 101.7625° E. This study identified the maximum solar irradiance for generating solar energy at hilly area projected at 1333.56 W/m2 compared to a flat area that received at 942.67 W/m2. It gives a review of the critical indicators that the solar industry looked forward to when dealing with site selection or the potential for the development of new solar power plants. Ampang receives between 1273.43 W/m2 and 1333.56 W/m2 at hilly area, suggesting that the sky is clear, and the sun is shining brilliantly for a significant portion of the year

Calcium bentonite vs sodium bentonite : The potential of calcium bentonite for soil foundation

Bentonite is a favourable candidate as a sealing material in the deep geological repository to safe storage of highly radioactive nuclear waste in several countries. The high swelling characteristic made bentonite famously type of clay that extracted from smectite group with the main mineral is montmorillonite that has a double diffusion layer. The benefits of sodium bentonite like Wyoming bentonite has proven in the industry. Research on modifying the properties of calcium bentonite to high swelling clay like sodium bentonite for it be able to benefit the industry has been done. Most of the research attempted to improve the workability of calcium bentonite as an alternative material for replacing sodium bentonite in construction industry; however, very little is known about using raw calcium bentonite to improve weak soil subgrades. This paper highlighted the usage of calcium bentonite adapted in construction industry especially in soil stabilization activity and some experimental analysis has been made on the type of calcium bentonite found in British Columbia min

MODIFICATION OF KAOLIN MINERALOGY AND MORPHOLOGY BY HEAT TREATMENT AND POSSIBILITY OF USE IN GEOTECHNICAL ENGINEERING

ABSTRACT: This paper presents an experimental work on the effect of heat treatment on the mineralogy and morphology of kaolin. Kaolin, which is moderately expansive, was preheated at temperatures ranging from 200°C to 800°C by increment of 200°C and cooled at room temperature before it was mixed with peat. Peat represents a compressible soil and has low bearing value. The main aim of the work is to study the effect of heat treatment on shear strength parameters of peat-kaolin mixture. The mixtures are prepared at different proportions, and at each proportion triaxial samples were prepared and tested in the undrained condition to study the shear strength parameters. Untreated kaolin-soil mix was also prepared to provide a comparison between the treated and untreated soil mix in terms of the shear strength behaviour. XRD and FESEM were also carried out to investigate the change in soil micro-structure due to heat treatment. The tests showed that there was a slight improvement in the strength of peat-kaolin mixture when kaolin was preheated to a temperature of up to 400°C. Finally results were discussed and conclusions were made for the preheated kaolin-peat mixture

The seismic resistance simulation for cracked clayey backfill

Applying nonlinear multidirectional forces to the earth retaining structure causes expansion and compression of existing soil crack and this phenomenon occurs in complicated form for clay. The cracked clayey backfill subjected to multi-directional seismic loads has not been reported in the literature. An analytical method was used for identifying the length of the crack. Two types of models with 7 and 15 cracks were assumed and simulated. By introducing the nonlinear extended finite element method (NXFEM), the nonlinear displacement, strain, and stress of the models were simulated. The results revealed that the number of the soil cracks modifies the vibration mechanism, nonlinear displacement, stress, and strain behavior of the model. The research methodology was validated by comparing the results of the numerical simulation with those available in the literature. The novelty of the present study is related to introducing NXFEM

The displacement simulation for cracked earth structure with different geometry

The strength of the material and safe economical design are important from the design point of the view in all branches of engineering. In many regions, the geographical characteristics of territory play important role in the design geometry of the backfill. In addition, using clayey soil to construct backfill results to have a crack in the cracked zone of the backfill. In the present study, the geometry of two different clayey soil backfill was investigated. The main aim of this study is for understanding the impact of the geometry of the model on the nonlinear displacement of the clayey soil backfill when the seismic load with equal magnitude is applied on the modelled clayey soil backfill. The results illustrate the seismic response and nonlinear displacement of the clayey soil backfill were modified by changing the geometry of the model. In point of view, to construct clayey soil backfill in a site needs to use different soil in constructing each clayey soil backfill concerning the geometry of the model. The novelty of this work introduces the concept of strength of the material association with the crack and geometry of the model in seismic design of the clayey soil backfill, considering the nonlinear displacement of the model in loading and reloading stages. Moreover, illustration of the nonlinear strain and nonlinear displacement of the model. The outcome of this investigation importantly explains the impact of model geometry in the cracks interaction, distribution of the displacement of the model, and displacement magnitud

Crack simulation for the cover of the landfill – A seismic design

The stability of the landfill is an environmental issue. The collapse of the landfill causes environmental pollution and influences human life. In the present study, the crack on the cover of the landfill was simulated. Rankine’s theory and the Phantom Node Method were used for the simulation length of the crack and the mechanism of the crack propagation in the nonlinear extended finite element method (NXFEM). Artificial Neural Networks (ANNs) based on Levenberg-Marquardt Algorithm and Abalone Rings Data Set mode were used to predict displacement in critical points of the model. The vibration mechanism of the landfill was changed in each model. During applying seismic load on the model, the optimized thickness of the clay cover on the landfill was discussed. The thickness of the landfill cover controls the seismic response of the landfill. The numerical simulation shows differential displacement of the landfill impacts on the crack propagation and the need for the appropriate design of the cover thickness of the landfill

Crack simulation for the cover of the landfill – A seismic design

The stability of the landfill is an environmental issue. The collapse of the landfill causes environmental pollution and influences human life. In the present study, the crack on the cover of the landfill was simulated. Rankine’s theory and the Phantom Node Method were used for the simulation length of the crack and the mechanism of the crack propagation in the nonlinear extended finite element method (NXFEM). Artificial Neural Networks (ANNs) based on Levenberg-Marquardt Algorithm and Abalone Rings Data Set mode were used to predict displacement in critical points of the model. The vibration mechanism of the landfill was changed in each model. During applying seismic load on the model, the optimized thickness of the clay cover on the landfill was discussed. The thickness of the landfill cover controls the seismic response of the landfill. The numerical simulation shows differential displacement of the landfill impacts on the crack propagation and the need for the appropriate design of the cover thickness of the landfill

The effectiveness of unmanned aerial vehicle (UAV) for digital slope mapping

This paper discusses the applications of unmanned aerial vehicle (UAV) for slope mapping and its important parameters including perimeter, area and volume of certain selected areas. Modern UAV able to take high quality image which essential for the effectiveness and nature of normal mapping output such as Digital Surface Model (DSM) and Digital Orthophoto. This photo captured by UAV will later transfer to commercial software to generate full map of study area. Three locations in Kuantan Pahang are chosen (Sungai Lembing, Politeknik Sultan Ahmad Shah ‘POLISAS’ and Pahang Matriculation College) for slope mapping. With the help of established software, the measurement (perimeter, area and volume) of selected study areas can be determined easily and considered as the main interest in this study. In addition, another outcome of this study is, this modern method of mapping will be compare to traditional method of mapping which proven to be more effective in term of low costing, low time consuming, can gather huge amount of data within short period of time, low man power needed and almost no potential risk of hazardous effect to man. In conclusion, modern technology of UAV proves to be very effective for mapping in geotechnical engineering. Slope mapping help researchers and engineers to obtain slope measurement within short period of time compare to previous traditional method

Waste to Product: Potential of Mg-Rich Gypsum Additive for Improvement of Peat Soil

The stabilization of problematic soils with chemical additives has increased in demand globally. Highly developed industrial plants have made an urgent need to utilize all types of soils even the problematic soils such as organic, marine clay, lateritic or expansive clay. The use of industrial waste by-products, namely magnesium-rich gypsum, for improving the weak characteristic of peat soil has not been investigated. This paper investigated the mechanism of gypsum that contributes to the compressibility of peat soil, a typical soil in Malaysia. The optimum combination of the additives into the soil was further examined by physicochemical properties by analytical techniques such as pH, scanning electron microscopy (SEM), X-ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR). This technical paper is more on comparison of theoretically analyzing the characteristics of peat and gypsum that have the potential to be strongly mixed and improve the characteristics of peat soil. The significance of this result shall contribute to the potential application of industrial waste by-products by recycling methods for soil improvement techniques