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Go to Editorial ManagerA series of unconfined compression and direct shear tests were carried out to investigate the compressive strength and shear strength parameters of clay soil reinforced with different contents and lengths of wheat straw and palm frond fibers and by adding different percentages of furnace slag. The bearing capacity and settlement characteristics of the rectangular footing based on a clay soil layer reinforced with wheat straw fibers, palm fronds and furnace slag at different thicknesses were also studied by conducting model footing tests. The results indicated that the compressive strength and shear strength parameters improved significantly when adding 0.5% of natural fibers and 20% of furnace slag. The maximum compressive strength of soil samples reinforced with wheat straw fiber MT1 and palm frond fiber MT2 was 365 and 407 kPa, respectively. Compared to the unreinforced sample, samples reinforced with natural fibers and furnace slag significantly improve the shear strength parameters c and ϕ . The cohesion of soil sample reinforced with wheat straw and palm frond fibers increased by 8% and 43% respectively, while the internal friction angles improved by 19% and 40% respectively. The sample treated with furnace slag MT3 showed improved significantly in cohesion by 76% and less effect in internal friction angle. Compared to unreinforced soil samples, the cohesion of soil samples reinforced with wheat straw and palm fibers and treated with furnace slag MT4 and MT5 increased by 77% and 92% respectively, and less effect in internal friction angle. Moreover, the bearing capacity and settlement characteristics of the rectangular footing improved significantly with the increase in the thickness of the top layer reinforced with natural fibers and treated with furnace slag. The ultimate bearing capacity of layer reinforced with wheat straw fibers MT1 increases to 193.2, 220.15 and 247.5 kPa at thicknesses of 0.5 B, 1.0 B, and 1.5 B respectively, while the settlement decreased by 10.4%, 15% and 20.48% respectively at same thicknesses.
The foundation of soil is considered safe when the factor of safety against shear failure is adequate and the settlement of the foundation should be tolerable and does not cause any unacceptable damage for the structure. The ultimate bearing capacity is defined as the maximum pressure which may be applied to the soil without causing neither a shear failure nor large settlement. In this research the bearing capacity of the soil at diesel power plant project in Al-Diwaniyah city by plate bearing test. The soil has been tested in the field in the locations of four foundations for circular tanks of diameter of 17m. The load is applied to the plate in four increments. In each increment; the load stays static for 15 minutes according to ASTM D1194-94 specification. The results showed that the plate settlements of the soil under three tanks were within the permitted settlement. The allowable bearing capacity of soils under these tanks were (117, 137 and 137) kPa respectively. While, the soil under the fourth tank was soft and the plate settled approximately 30 mm immediately after applying the first increment of load. Therefore the soil is considered improper and recommendations are suggested to improve it.
This paper presents an exact solution for the load settlement relationship of axially loaded piles embedded in nonhomogeneous elastic foundation. The governing differential equation is reduced to modified Bessel equation of order v. The solution is represented by Bessel's functions of the first kind of order v. The stiffness coefficients are then derived from the exact solution. Numerical comparison with approximate solutions of special cases verify the accuracy and efficiency of the adopted method.
Although estuarine locations provide natural safety and protection for the construction of harbours and other infrastructure, they are prone to natural filling due to sediment settlement. As a result, dredging is required regularly to keep navigation channels and harbours safe and functional. A numerical model has been developed in this study to compute annual sediment load in Khour Al-Zubair Port, South of Iraq, setting up a MIKE 21 FM model. MIKE 21 FM was developed by the Danish Hydraulic Institute (DHI) where provides the capability of simulation of a hydrodynamic model (HD) coupled with the mud transport model (MT). The model operates with an unstructured mesh of triangles and quadrilateral elements of different sizes. Field and experimental data were provided during two periods (Neap and Spring) for calibration and verification process. According to the sensitivity analysis results, it is clear that the settling velocity is an essential parameter. Based on the results of the calibrated model, there is annual sedimentation of 1220500.64 tons/year. The primary deposition took place in the meandering of the Khour Al-Zubair estuary and behind the piers.