One of the Iraqi geotechnical problems is the presence of gypseous soils covering about (27-36) percentage of Iraq soils containing gypsum between (10-70) ratios. The main reason for soil problematic is the gypsum dissolution when these soils are inundated. However, the soluble gypsum can be leached out of the soil particles, so these problems can be led to cracking, tilting, and collapsing the related soil structure and changing the soil properties. The aim of this work is to investigate the performance of under-reamed piles as a new, improved method to reduce the moisture sensitive and the primary triggering mechanism for the volume reduction of collapsible soil, which is considered as a non-elastic deformation; this was done by carrying series of inundation these soil with using different types of under reamed piles to arrive the best and suitable type useful in gypseous soils. The piles with reams are concrete piles with one or more ream, so under-reamed piles are suitable in weak soils where sizable ground movement, variations, filed up ground, silty clay, and loose sand which has the advantage to increase the soil strength. This paper includes the experimental model of under-reamed piles under static load simulated by a steel plate on the pile cap, then the load-settlement curve, friction force, and bearing force founded from the investigation of different patterns of reamed. It was found that a number of bulbs had a significant reduction on settlement reach to 93% in case of using triple under-reamed pile which is the greatest results in comparison with other patterns and reference pile of the uniform cross-section in the wet state.
Khabaz Oil Field is located in Kirkuk, about 20 Km southwest of Kirkuk City between Jambour and Bai Hassan oil fields. Tectonically, it is located on the Unstable Shelf within the Low Folded Zone (Zagros Fold Belt). Six wells in Khabaz oil field with two seismic lines (Line K8 and KK54) are used to conduct the geometric analysis, which include the description of fold and fault systems for the purpose of understanding the structural setting of Jeribe (Early Miocene) and Azkand (Late Oligocene) formations in this field. Khabaz structure is a double plunging positively inverted subsurface asymmetrical anticline influence the whole pre-Holocene sedimentary sequence. The interlimb angle of this structure ranges between 137º to 151º which is classified as a gentle anticline. The dip values of the axial surface range between 82 – 84º, so it can be classified as an upright fold with a general trend NW-SE. The core of the anticline is bounded by two high angle dipping reverse fault splay dipping toward each other. These faults pushed the core of the anticline upward with respect to the limbs of the structure. The Southwestern limb is affected by several high angle inverted faults that were possibly bifurcated from one or two major faults. The Northeastern limb is also influenced by a series of high angle reverse, some are dipping toward the core of the structure and few others are dipping toward the limbs. Some of these faults especially those influenced the southwestern limb of the anticline were inherited from the original normal faults that bounding the graben structure developed during the deposition of the Shiranish Formation. During the Late Plio-Plistocene contraction phase, the sense of slip on these faults were inverted and the faults migrated upward into the Tertiary sequence resulting in the formation of the positively inverted structure.
Background: Many tools and techniques have been recently adopted to develop construction materials that are less harmful and friendlier to the environment. New products can be achieved through the recycling of waste material. Thus, this study aims to use recycled glass bottles as sustainable materials. Objective: Our challenge is to use nano glass powder by the addition or replacement of the weight of the cement for producing concrete with enhanced strength. Methods: A nano recycled glass powder is prepared by crushing and storming a glass bottle to obtain a Blaine surface area of approximately 28 m2/g and conforming to the chemical requirements for natural pozzolana class N, according to ASTM C618. The outcome of using nano recycled glass for theaddition and replacement of ordinary Portland cement weight on the compressive and flexural strengths of concrete at 7, 28, and 90 days is investigated. Results: The concrete mixes with 2.5%, 5%, 7.5%, and 10% replacements of cement by nano recycled glass powder show improvements in compressive and flexural strengths of up to 12.77% and 7.66%, respectively, at 28 days. Meanwhile, mixes with the addition of 5% nano glass powder show best improvements in compressive and flexural strengths of up to 11.49% and 7.46%, respectively.
The present paper presents the contribution on the performance enhancement study of a regenerative Ljongstrom type air preheater. The experimental analyses are carried out to study the performance enhancement of the system by regular artificial roughening of the heat transfer elements using pin-shaped turbulators (promoters). An experimental test rig is designed and fabricated to simulate the transient operation of the rotary air-preheat system. To study the hydraulic and thermal processes and their combined influences on the system performance, the friction factor and the convection heat transfer coefficient, with and without the turbulators, were evaluated from experimental measurements. The investigations have been carried out under various designs and operational conditions. The results were obtained and presented for Reynolds number in the range of 0.93 x 10 5 to 2.35 x 10 5 in the thermal discharge period and 0.58 x10 5 to 1.8 x 10 5 in the thermal charging period. The roughening effect was also investigated by varying the pin pitch to pin height ratio, P/e; additionally, the effect of the thermal elements numbers in the working section was considered. The artificial roughening by the pins enhanced the performance of the rotary air preheater, and best results have been achieved at P/e=10.
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