https://file.scirp.org/pdf/ENG20121100015_39355361.pdf

Evaluation of the Ultimate Capacity of Friction Piles

https://file.scirp.org/pdf/ENG_2013042914410173.pdf

New Method for Prediction Pile Capacity Executed by Continuous Flight Auger (CFA)

The estimation of axial load carrying capacity of bored piles is a complicated problem because it depends upon number of factors which may include boring method, concrete quality, concreting method, experience of the staff and the ground conditions. Validation of pile design through testing of piles either test piles or working piles is considered an essential part of deep foundation design. This is recognized as being the most reliable means of dealing with the uncertainties that may rise during design and construction phase of pile foundations. In this paper, different theoretical methods have been used for the evaluation of pile capacities and then their comparison with the pile load test evaluations have been made for the project of Rathoa Haryam Bridge being constructed in Mirpur Azad Jammu & Kashmir at Mangla reservoir. The subsoil at the bridge site consists mostly of lean clay with ground water table at a shallowest depth of 0.3 m below NSL during the period of field investigations. Six pile load tests have been conducted on test piles with length in the range of 35 m and 45 m and with diameter of 1000 mm. Based on pile capacity analysis, it has been revealed that the theoretical method for pile capacity estimation by NAVFAC DM 7.02 gives 20% to 40% lesser pile capacity relative to the pile capacity evaluated from pile load test data. The SPT method proposed by Decourt gives higher pile capacity relative to the pile capacity derived from pile load test data and therefore, it is not recommended to be used for cohesive soils. The CPT based methods suggested by Schmertmann and Philipponnat give close results to each other but with a difference of 10% to 20% relative to the pile load test interpretation and may be considered reliable methods for cohesive soils. Pile capacities from the pile load test interpretation by Limit Value method and 90% Hansen method match closely whereas the 6 mm net settlement method gives slightly lower estimate of pile capacity as compared to the other load test methods. The best approach for pile capacity evaluation from pile load test data is to use the average value of pile capacity of all the load test interpretation methods.

/pdf/comparison-of-ultimate-pile-capacity-based-on-theoretical-h3g3u5ar0u.pdf

Comparison of Ultimate Pile Capacity Based on Theoretical and Pile Load Test Methods

As a part of a larger study which aims to develop enhanced gravity foundations for marine energy generators, field investigations and laboratory interface testing were carried out in order to explore the shear behaviour of rock-steel interfaces at relatively low normal stresses, similar to those encountered at foundation-seabed interfaces. Results revealed that the shear strength of the interface reduces with increasing compressive strength of the rock analogue but increases with increasing roughness of the steel.

Proceedings of the Thirteenth BGA Young Geotechnical Engineers' Symposium

Excessive emission of sulfur dioxides from the combustion of coal and other fossil fuels for thermal and industrial purposes has been associated with serious environmental hazards. Biodesulfisation (BDS) can be an effective approach for reducing the impact of toxic gases to its inbuilt operational feasibility under ambient environmental conditions. In the present research, two strategies for BDS of a standard organosulfur compound such as dibenzothiophene (DBT) were investigated under laboratory conditions. In the first treatment, the role of different surfactants such as Tween‐20, Tween‐80, SDS, and EDTA on the desulfurization of DBT was investigated by the application of bacterial consortium IQMJ‐5. In the second treatment, Iron oxidenanoparticles were synthesized and immobilized on the surface of bacteria cells. Shake flask experiments were conducted with immobilized cells, surfactant amended immobilized cells, and control or noncoated cells. Among different surfactant treatments, Tween‐80 was found to be the most effective surfactant, showing maximum desulfurization activity at a concentration of 5 g/L. The transmission electron microscopy and X‐ray diffraction analysis indicated that produced nanoparticles were spherical in shape with a size of about 46 nm and had a stoichiometric ratio of 55.85% and 44.15% between O and Fe, respectively. The nanoparticle treatment enhanced the DBT desulfurization process up to 11.37% as compared to the control, specifically when immobilized cells were used. Therefore, it was concluded that nanoparticles treatments with immobilization of the bacterial cells enhanced the desulfurization rate of DBT under ambient reaction conditions and provide a sustainable alternative for commercial coal BDS.

Response of mixed bacterial culture towards dibenzothiophene desulfurization under the influence of surfactants and microscopically (SEM and TEM) characterized magnetic Fe3O4 nanoparticles

Biodesulfurization is a promising approach, capable of reducing the sulfur content of recalcitrant sulfur-containing heterocyclic compounds such as dibenzothiophene and their alkylated derivatives. The performance of bio-desulfurization is undoubtfully dependent on different operating parameters. The effect of different process parameters on the growth rate and desulfurization capability of the bacterial consortium IQMJ-5 have been examined. The parameters that were optimized include the temperature of incubation, initial pH of the medium, and DBT concentration. In addition, the effect of several carbon and sulfur compounds on the growth of bacterial consortia IQMJ-5 was also analyzed. Moreover, the concentration of the most effective carbon compound was also examined in shake flask fermentation. The results showed that 25 º C temperature, 7.6 pH, and 0.3 mM DBT were the optimum conditions for the highest growth and desulfurization of the DBT. In addition, glycerol and Na 2 SO 4 were the bioavailable carbon and sulfur sources respectively, at which the consortium IQMJ-5 showed maximum growth. Moreover, 2gL -1 glycerol appeared as the carbon concentration at which the consortium IQMJ-5 showed the highest activity. An enhanced rate of desulfurization was encountered when a medium with optimized conditions was employed, compared to non-optimized conditions. The current research study uncovered the potential of the bacterial consortium IQMJ-5 to desulfurize sulfur-containing organic compounds at the optimized conditions of different process parameters.

/pdf/optimizing-the-metabolic-performance-of-mixed-bacterial-2axz1fo7.pdf

Optimizing the Metabolic Performance of Mixed
Bacterial Culture Towards Dibenzothiophene
Desulfurization under the Effect of Varying
Nutrient and Environmental Factors

The precise prediction of maximum load carrying capacity of bored piles is a complex problem because it is a function of a number of factors. These factors include method of boring, method of concreting, quality of concrete, expertise of the construction staff, the ground conditions etc. besides the pile geometry. The performance of pile load tests is, therefore, of paramount importance to establish the most economical design of piles especially where bored cast-in-situ piles are to be provided to support a structure. This paper describes the experience gained from four pile load tests at a site in the North West Frontier Province of Pakistan where a new cement plant is going to be installed. Geotechnical investigations at the site were carried out to a maximum depth of 60 m. The subsoils at the site are predominantly hard clays within the investigated depth with thin layers of gravels / boulders below 40 m depth. Perched water was encountered at various horizons. Four piles of diameter varying from 660 mm to 760 mm and length ranging between 20 m and 47.5 m were subjected to axial loads. The load test data were analyzed using various state of the art techniques including intercept of two tangents, point of change of slope, 6 mm net settlement [1], 90 percent and 80 percent Hansen [7], limit value Davisson [2], and Chin [3]. Based on a comparison of pile capacities from these methods with the theoretical values, recommendations are made on the approach to estimate the pile capacity in hard clays. Using the pile load test results, back calculations were also carried out to estimate the appropriate values of pile design parameters such as undrained cohesion and adhesion factor.

/pdf/shaft-friction-of-bored-piles-in-hard-clay-1rpj1caiyf.pdf

M. S. Qureshi

Papers

Optimizing the Metabolic Performance of Mixed Bacterial Culture Towards Dibenzothiophene Desulfurization under the Effect of Varying Nutrient and Environmental Factors

Shaft Friction of Bored Piles in Hard Clay