Articles

  1. NUMERICAL ANALYSIS OF INFILTRATION INTO PERVIOUS CONCRETE-BASE SYSTEMS Download Article

    Bertrand Teodosio, Jaehun Ahn and Hyun-Suk Shin
    • Article Type: Research Article
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    • Pages (1117-1122 )
    • No of Download = 907

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    Decrease in pervious area due to urbanization and rainfall intensification because of climate change prompted to reconsider our philosophy in stormwater management. One of the innovative approaches for stormwater management is a concept called Low Impact Development (LID). Among other techniques of LID, construction of pervious pavement can utilize vast paved surfaces, traditionally impervious, allowing stormwater to infiltrate through its surface. In this study, the hydrologic performance of a particular pervious concrete system section was investigated using Finite Element Method (FEM) modelling. The influence of initial saturation and rainfall intensity to produce run-off were examined to imply possible design considerations. Further, rainfall data recorded from July 15, 2012 at Busan, South Korea were employed to investigate the effects of evaporation and underdrain in the hydrologic capacity and behavior of the pervious concrete system. The results and implications to hydrological design are discussed herein.

  2. INTERACTION ANALYSIS FOR OIL STORAGE TANK ON MARINE CLAY Download Article

    Pallavi Badry and Neelima Satyam D.
    • Article Type: Research Article
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    • Pages (1123-1129 )
    • No of Download = 759

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    The engineering behavior of marine clay is very different than that of the moist and dry clay because of its structural and mineral composition [1]. Marine structure is subjected to the waves which create a cyclic stresses inside the soil mass [2]. The huge storage tanks experiences a heavy wind and current load which produces a adverse effect in the soil settlements. In this paper a cylindrical reinforced cement concrete tank with diameter 100 m and 40 m height founded on soft marine clay of undrained shear strength of 10 kPa is considered for the analysis. The huge pile group is modeled by equivalent pier method and interaction factor method for the full and empty loading conditions. Settlement including the soil pile interaction has been estimated for both the cases mentioned above for different pile configuration including pile length, diameter and spacing of piles in a group. It has been observed that the spacing of the piles plays a vital role in estimating the settlements and stresses. With the comparison of the equivalent pier method (EPM) [8] and interaction factor method (IFM) for settlement estimation, the later is found to be more suitable for interaction analysis to achieve the safety of the tank.

  3. AMMONIA REMOVAL CHARACTERISTICS OF POROUS CONCRETE WITH ZEOLITE FOR ENHANCING SELF-PURIFICATION ABILITY IN RIVER SYSTEM Download Article

    Fumitake Nishimura, Toshio Yamada, Motohiro Tanaka, Hirofumi Kassai and Michiko Masuda
    • Article Type: Research Article
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    • Pages (1130-1137 )
    • No of Download = 926

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    Ammonia removal characteristics of porous concrete with zeolite are investigated. Ammonia is one of the common pollutants in river water, and it can cause several adverse impacts for human activities such as water supply and agricultural purposes. It has negative impacts on water ecosystem as well. Porous concrete with zeolite can adsorb ammonia by zeolite, and biological nitrification and its promotion can be expected because attached ammonia on the surface of the porous concrete can promote bacterial growth of nitrifying bacteria. It is expected that both chemical effects (ammonia adsorption) and biological effects (nitrification) can remove ammonia effectively from river waters when the porous concrete is applied in the river as an artificial riverbed for example. Experimental discussion is conducted in this study. It was shown that the specific surface area was increased by making porous concrete, and the ammonia removal rate can be increased twice as a result. It was made clear that chemical effect can be produced in the same level as biological effects as well. It is considered that both effects can increase the ammonia removal ability of porous concrete with zeolite effectively.

  4. DESIGN DROUGHTS: A NEW PLANNING TOOL FOR ECOSYSTEM REHABILITATION Download Article

    Devanmini Halwatura, Alex M. Lechner and Sven Arnold
    • Article Type: Research Article
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    • Pages (1138-1142 )
    • No of Download = 638

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    Droughts are one of the most devastating natural hazards, often causing severe economic and environmental damage. Across Eastern Australia climate is highly variable and frequent floods and droughts affect large areas over prolonged periods of time. Understanding the variations and trends in these weather extremes is critical for ecologists to assess the adequacy of management plans for anthropogenically affected landscapes such as agricultural or post-mining land, where water often plays a critical role for ecosystem persistence. In this study we use a new approach developed as a management and/or risk assessment tool for degraded land rehabilitation to quantify periods of water deficit using the severity-duration-frequency (SDF) of rainfall, known as design droughts. This approach is based on the intensity-duration-frequency (IDF) design rainfall concept used by engineers for designing hydrological infrastructure. This study focuses on analysing drought events of four selected locations (Cairns, Melbourne, Wagga Wagga, Quilpie) across Eastern Australia using the Reconnaissance Drought Index (RDI). We used monthly total rainfall and evaporation data of the past 40 years (1972-2013) to identify drought events. We categorised the drought events according to their severity and duration and analysed separately the historic time series as two parts of 20 years (1972-1992 and 1993-2013). We calculated the recurrence intervals of droughts to assess trends in the occurrence of drought events. Results show that the recurrence intervals of Melbourne and Quilpie barely changed over time, while the drought recurrence intervals decreased in Wagga Wagga and Cairns. These findings have critical implications for any rehabilitation and management plans for post-mining and agricultural land.

  5. SLOPE STABILITY AND ROCKFALL HAZARD ANALYSIS IN OPEN PIT ZINC MINE Download Article

    Maged Almandalawi, Greg You, Peter Dahlhaus, Kim Dowling and Mohannad Sabry
    • Article Type: Research Article
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    • Pages (1143-1150 )
    • No of Download = 749

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    Rockfalls are a major safety hazard in open cut mines, particularly in large-scale deep pits. The geotechnical design relies on in-situ, site-specific, rock slope data to predict the trajectories and velocities of rockfalls that present a residual hazard in the mines. This paper presents slope stability analyses using both static general limit equilibrium methods and finite element stress analyses to estimate unstable areas and slope displacements in the mid-west slope at Glencore Zinc’s Handlebar Hill Open Cut mine at Mt. Isa, Queensland, Australia. A conventional program -RocFall- was used for the slope rockfall risk assessment. Results indicate the possible slope benches involved in the initiation of rockfalls, and the maximum run-out distance, which could be defined as the pit's hazardous zone. A rockfall restraining system to absorb the impact energy of boulders and prevent them further falling was also modelled.

  6. DETERMINATION OF SLIP SURFACES IN FRACTURE ZONE LANDSLIDES USING ORIENTED BOREHOLE CORE SAMPLES Download Article

    Tsunataka Furuya and Jing-Cai Jiang
    • Article Type: Research Article
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    • Pages ( 1151-1158 )
    • No of Download = 1140

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    In situ and laboratory observation, geophysical measurement and digital imaging analysis of oriented borehole core samples are performed to determine slip surfaces in two large fracture zone landslides in Shikoku, Japan. The following data are obtained from each oriented borehole: (1) a depth distribution of rock quality designation, magnetic susceptibilities, the Equotip hardness values and wet unit weight of core samples, (2) geometric orientation of geologic discontinuities (cracks, joints, faults, etc.), and (3) a depth distribution of numerical color values from digital imaging of borehole core samples. As a result, the rock quality designation, the Equotip hardness value and unit weight, and the orientation of cracks and joints showed a clear change near the slip surfaces respectively, but the digital color values clearly varied only in one of the landslides and no change of magnetic susceptibility of core samples was found at both sites. The results demonstrate that it is capable of locating the slip surface in a fracture zone landslide by using the above-mentioned data in combination.

  7. ENGINEERING PROPERTIES OF BLACK COTTON SOIL-DOLIME MIX FOR ITS USE AS SUBBASE MATERIAL IN PAVEMENTS Download Article

    S. Patel and J. T. Shahu
    • Article Type: Research Article
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    • Pages (1159-1166 )
    • No of Download = 1107

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    In this paper, an attempt is made to stabilize problematic expansive Black Cotton (BC) soil by dolime fines for its use in subbase course of flexible pavements. Atterberg limits, free swell index, compaction characteristics, unconfined compressive strength (UCS), soaked CBR, shear strength parameters and resilient modulus are evaluated for different trial mixes cured up to 28 days. BC soil stabilized with a minimum dolime content of 9% satisfies the criteria recommended by Indian Road Congress for utilization in subbase layer of flexible pavements. The effects of dolime content and curing period on the above geotechnical properties of the mixes were investigated. Empirical relationships are developed to estimate important design parameters such as deviator stress at failure and cohesion of the stabilized mix that can be used to determine dolime content to achieve a target strength within a given curing period. Different empirical models are proposed to estimate the resilient modulus of soil-dolime mixes and their performances for the prediction of resilient modulus are compared.

  8. NUMERICAL ANALYSIS ON THE EFFECT OF JET GROUT PILES ON AN EXCAVATION LOCATED IN AN URBAN AREA Download Article

    Akula Pavan and Thiruvengadam Tamilmani
    • Article Type: Research Article
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    • Pages (1167-1171 )
    • No of Download = 974

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    The development of infrastructure in limited land space is a challenging scenario. Infrastructure in limited land space regions (e.g. Singapore) does not provide freedom to develop at favourable locations instead forces the engineer to design at the possible locations. Clay with high organic content, commonly referred as Peaty clay is predominant in coastal areas. This clay being highly acidic (PH>7) and possessing very low shear strength is a critical factor to the design of infrastructure in the vicinity. Ground improvement adopted weak strata will have varying effect and may not be able to achieve the required strength. This paper discusses the effect of ground improvement (Jet Grout Piles) on the sloped excavation predominantly in Peaty clay. A 15m deep excavation which is 60 m wide is used for the Finite element modeling. Impact study on a tunnel located 40m from the excavation is presented (The study is carried out for various achieved Jet grout piles strengths of 100, 200, 300, 400 and 500 kPa). The stability of the slopes for the various strengths is also discussed (GeoSlope was used as the medium to perform the geotechnical analysis).

  9. TEMPERATURE EFFECTS ON GEOTECHNICAL AND HYDRAULIC PROPERTIES OF BENTONITE HYDRATED WITH INORGANIC SALT SOLUTIONS Download Article

    H. M. A. Rashid, K. Kawamoto, T. Saito, T. Komatsu, and P. Moldrup
    • Article Type: Research Article
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    • Pages (1172-1179 )
    • No of Download = 816

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    This study investigated the combined effect of temperature and single-species salt solutions on geotechnical properties (swell index and liquid limit) and hydraulic conductivity of bentonite applying different cation types, concentrations, and temperatures. Results showed that both the swell index and the liquid limit decreased with an increase in salt concentration irrespective of the type of cation. Monovalent cations showed higher values of the swell index and the liquid limit compared to divalent cations. In general, the swell index of bentonite increased whereas the liquid limit decreased with increasing temperature for all cation types and concentrations. Significant and high correlations were found between swell index and liquid limit of bentonite at all three temperatures. Hydraulic conductivity of bentonite was found to increase with increasing temperature. No significant change in hydraulic conductivity with time was observed for all concentrations and cation types, and, overall, concentration and valance of cations had little effect on the hydraulic conductivity of bentonite.

  10. UPTAKE OF ADVANCED AND SUSTAINABLE ENGINEERING MATERIALS IN CIVIL INFRASTRUCTURE PROJECTS Download Article

    David S Thorpe
    • Article Type: Research Article
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    • Pages (1180-1185 )
    • No of Download = 938

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    Advanced and sustainable engineering materials, such as engineered fibre composites, geoploymer cement, and recycled concrete have the potential to reduce demand on scarce resources, improve safety, reduce greenhouse gas emissions and contribute to positive initiatives in civil engineering design and construction in areas like foundations and structural members. For example, engineered fibre composites can replace other materials (such as timber), because of their high strength to weight ratio, light weight and ease of installation. They can also have positive impacts on sustainability. While advanced materials have several advantages, their take-up by industry, and in particular small and medium enterprise companies (SMEs), has in a number of cases been relatively slow. This is likely to be the result of a number of factors, such as relatively high cost, financial risk in using an unproven technology, lack of suitable design standards, an unproven life cycle, uncertainty over long-term sustainability issues, and possible changed building and construction methods. Advantages and disadvantages of the use of selected advanced and sustainable materials in civil engineering projects are investigated. A weighted scoring methodology for improved evaluation of their advantages and disadvantages, with a view to aiding decisions, is proposed.

  11. A COMPARATIVE STUDY ON THE RESISTANCES OF BUCKET FOUNDATION IN SAND WITH DIFFERENT INSTALLATION METHODS Download Article

    Ju-Hyung Lee, Jin-Ung Do and Sung-Ryul Kim
    • Article Type: Research Article
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    • Pages (1186-1189 )
    • No of Download = 876

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    Model tests have been performed to investigate the vertical, horizontal and cone tip resistances of bucket foundations embedded in sand with different installation methods; suction force by pump and jacking force by actuator. Micro-cone penetrometer was used to evaluate the variation of the effective stress inside pile after model pile installation. As a result, in vertical pull-out test, the pile installed jacking force method shows 3 times larger resistance than installed suction force method. In horizontal pull-out test, the ultimate horizontal capacity and the slope of load-displacement curve for the model pile installed by suction force were decreased by 22% and 40% respectively compared to the pile installed by jacking force. In cone penetration test, inside cone tip resistance of the pile installed by suction force shows about 40% smaller than that installed by jacking force. It is because the effective stress was reduced due to upward seepage of inner pile in sand by suction force. Therefore, we can see that the effect of installation method on bucket foundation has to be considered to investigate the behavior of it experimentally.

  12. SIMULATION OF REACTIVE GEOCHEMICAL TRANSPORT PROCESSES IN CONTAMINATED AQUIFERS USING SURROGATE MODELS Download Article

    Hamed Koohpayehzadeh Esfahani and Bithin Datta
    • Article Type: Research Article
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    • Pages (1190-1196 )
    • No of Download = 480

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    Transport of contaminant species undergoing chemical reactions in groundwater aquifers is a complex physical and biochemical process. Simulating this transport process involves solving complex nonlinear equations and requires huge computational time for a given aquifer study area. Development of optimal remediation strategies in aquifers may require repeated solution of such complex numerical simulation models. To overcome this computational limitation and improve the computational feasibility of large number of repeated simulations, Genetic Programming based trained surrogate models are developed to approximately simulate such complex transport processes. Transport process of acid mine drainage, a hazardous pollutant is first simulated using a numerical simulated model: HYDROGEOCHEM 5.0 for a study area resembling a mine site. Simulation model solution results for an illustrative contaminated aquifer site is then approximated by training and testing a Genetic Programming (GP) based surrogate model. To decrease the total number of GP formulations, the coordinates of observation locations are implemented as input data in the surrogate models. Comparison of the surrogate models and numerical simulation results show that the surrogate models can provide acceptable approximations of this complex transport process in contaminated groundwater aquifers.

  13. APPLICATIONS OF INNOVATIVE MATERIALS FOR PERFORMANCE IMPROVEMENT OF FLEXIBLE PAVEMENT OVER EXPANSIVE SUBGRADE Download Article

    Ravin M. Tailor and Dr. Navin C. Shah
    • Article Type: Research Article
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    • Pages (1197-1202 )
    • No of Download = 1062

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    Expansive soils are one of the most problematic materials that are widely encountered in significant land areas in several parts of the world; like Africa, Australia, India, United States and Canada. The South Gujarat region in India have majority of top soil as black cotton soil. The black cotton soil has characteristics of shrinking on drying and heaving on wetting. This soil being expansive creates several types of damages to pavement structures, and in some cases the pavement may even become unserviceable. The normal climate condition of study area shows short wet and long dry period which aggravate the problem of swelling and shrinkage. The IRC: 37 – 2001, Annexure – 4 suggest 0.6 to 1.0 m thick non-cohesive soil cushion on the expansive soil for road construction which led to higher cost for road construction. Also for new urban areas it is difficult to raise the embankment or to excavate the subgrade upto such a depth due to existing structures and under laying service lines. To provide economical solution along with feasible application two innovative materials were used namely, CONSOLID and Geotextile for flexible pavement. The CONSOLID application shows the great improvement of CBR values helping the overall stability of the pavement. The Geotextile provided below the pavement components to act against the heaving of the swelling soil at the same time it helps as drainage layer also. Field study is undertaken to observe the effect of Geotextile in flexible pavement performance and 2 specific boundary conditions are created for observations. The Observations shows about 50 % reduction in shrinkage effect for paved road reinforced with Geotextile subjected to drying and wetting cycles. Both the materials are having its unique advantage in the performance improvement of flexible pavement over expansive subgrade.

  14. REMOVAL OF CESIUM FROM SEA SLUDGE THROUGH DECOMPOSITION OF ORGANIC MATTER WITH AQUEOUS HYDROGEN PEROXIDE Download Article

    Hirosuke Hirano, Takeshi Toyama, Nobuyuki Nishimiya and Kyoichi Okamoto
    • Article Type: Research Article
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    • Pages (1203-1206 )
    • No of Download = 883

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    The radioactive cesium scattered from the Fukushima Nuclear Power Plant has caused a pollution problem in Japan. To tackle such accidents, many technologies have been developed to remove radioactive cesium from water. However, the technology to decontaminate the sludge is much less advanced than that for water. Thus, we focus on the decomposition of organic matter by H2O2 for decontaminating the sludge. The maximum decontamination of the sea sludge by H2O2 was found to be 2.6 times higher than that by water alone, and the greatest decontamination was obtained using 34.5% H2O2. We believe the extent of decontamination increased for this solution because the solution pH was near the pHpzc, which would suppress the ability of the sludge to absorb Cs ions. We also examined the effect of time on the decontamination of the sea sludge; however, only a small increase in decontamination (1.7 times the initial value) was observed.

  15. ASSESSMENT OF HUMAN RISKS POSED BY DEADLY DEBRIS FLOW IN THE WENCHUAN EARTHQUAKE AREA Download Article

    Shuai Zhang and Limin Zhang
    • Article Type: Research Article
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    • Pages (1207-1211 )
    • No of Download = 604

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    Prolonged rainstorms had triggered several large-scale debris flows along Provincial Road 303 near the epicenter of the 2008 Wenchuan earthquake. A lot of concrete-aggregate plants distributed along this road were buried by the runout debris, leading to a large number of fatalities. A Quantitative Risk Assessment (QRA) methodology is being developed for debris flows induced by various rainfall scenarios. QRA for these debris flow hazards is of significance to determine the probability distribution, consequence and human risk profile arising from these disasters. With the aid of Geographic Information System (GIS) platform, a potential channelized debris flow catchment in the study area is identified based on remote sensing images and field study. Rainfall intensity-duration thresholds for the local channelized debris flows are used to determine the occurrence probability under six rainfall scenarios for the purpose of hazard analysis. Subsequently, human losses of debris flow are assessed by considering the variations of rainfall events, and the final human risks can be obtained using a general risk model. Finally, the societal human risks are obtained, which provide a benchmark for studying the long-term human risks of these potential debris flows and engineering decision in the perspective of mining manufacture.

  16. SEEPAGE FLOW-STABILITY ANALYSIS OF THE RIVERBANK OF SAIGON RIVER DUE TO RIVER WATER LEVEL FLUCTUATION Download Article

    A. Oya, H.H. Bui, N. Hiraoka, M. Fujimoto, R. Fukagawa
    • Article Type: Research Article
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    • Pages (1212-1217 )
    • No of Download = 1089

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    The Saigon River, which flows through the center of Ho Chi Minh City, is of critical importance for the development of the city as forms as the main water supply and drainage channel for the city. In recent years, riverbank erosion and failures have become more frequent along the Saigon River, causing flooding and damage to infrastructures near the river. A field investigation and numerical study has been undertaken by our research group to identify factors affecting the riverbank failure. In this paper, field investigation results obtained from multiple investigation points on the Saigon River are presented, followed by a comprehensive coupled finite element analysis of riverbank stability when subjected to river water level fluctuations. The river water level fluctuation has been identified as one of the main factors affecting the riverbank failure, i.e. removal of the balancing hydraulic forces acting on the riverbank during water drawdown.