The earth-fill dams are simple structures which are able to prevent the sliding and overturning because of their self-weight. Due to lack of suitable clay materials, the dams may be designed as zoned core which is composed of three vertical zones contains central impermeable core and two permeable shells on their two sides of the core. Impervious core is used in zoned earth dam to reduce the quantity of seepage through the body of the dam and to relief part of risk of piping and erosion in the downstream side. This study aims to study the soil properties that is used as a core of earth dam through a series of laboratory experiments that were carried out a several soil samples mixed with both lime and silica fume, in order to stabilize the soil. The process of stabilization aims to increase the soil strength and reducing its permeability and compressibility. Test results show that adding lime and silica fume to the soil decreases the permeability of soil with different cases of study, the percentage of decreases in case of standard compaction about (21%-90%) while in modified compaction test the permeability decreases in range (41.7%-91.3%). Also the unconfined compressive strength of the soil increasing significantly in both cases of compaction which were standard and modified. When add the materials, these values were increased in range (76%-90%) for samples from standard compaction test, while it being (0.21%-42%) in modified compaction test.
A study of Al-Rayhanna Bridge (Iraq, Anbar Province) concerned with examining elastomeric bearing pad dynamic behaviour against changes in traffic speed and girder deflection. The areas of maximum deflection were being located at midspans of the girders, especially under truck or underneath truck lanes. One of the key contributions of the work was the application of the deflection measurements of the Linear Variable Differential Transformer (LVDT) for the estimation of car speeds, and a very welcoming mean value of 40.95 km/h (the visual timing correlations being >95 per cent), showed that structural measurement can be employed in reliable traffic analysis. The new bridge was defined by reduced damping ratio (3-4 % compared to 5-6 % of the old bridge) accounting for varying abilities to absorb and release energy. Thus, the new bridge appeared to require less balance restoration energy (1.5-2 seconds / 0.5-0.67 Hz) than the old bridge exhibiting faster stabilization (1-1.5 seconds / 0.67-1 Hz). The rate of amplitude decay also varied quite radically: 20-25 per cent per cycle for the new bridge compared to 30-35 per cent for the old bridge. Structural design and climatic dependent factors , indicates the significant role played by adopting dynamic factors - such as damping, energy dissipation and deflection patterns in bridge structure design and maintenance to guarantee long-lasting structural integrity and safety. These observations give conclusive feedback on upcoming resilient bridge construction, also the field of material science and traffic engineering
Organic soils are problematic soil for various engineering applications due to their high compressibility and low shear strength which need to be improved. For many soil improvement techniques, using waste materials, such as fly ash (FA), is a practical and sustainable process. In this research, FA and geopolymer were used e used to reduce organic soil's compressibility. A one-dimensional consolidation test was performed to evaluate the organic soil's consolidation and compressibility properties. The geopolymer was prepared using 20% FA and of sodium hydroxide ratio and sodium silicate alkali solutions. The geopolymer specimens were first cured for 2 hours at 45 and 65 oC, then cured for further 28 days at room temperature. The consolidation test results showed that FA-based geopolymer is effective in stabilizing organic soils due to the observed improvement in the compressibility, consolidation, and permeability characteristics. The compression index decreased by 98.16%, and the permeability decreased by 95%.
The aim of this study is to investigate the effect of adding recycled materials such as CKD and RAP to weak cohesive soils, in addition to evaluate the change in the strength of these soils. This study was conducted on soil type MH, and only RAP particles finer than 10 mm were used in preparing the mixtures. 7, 14, and 28 days were selected as curing periods for soil- CKD and soil- CKD- RAP mixtures to obtain the effect of curing periods on soil improvement. The results showed that adding 20% of CKD to the natural soil increased the unconfined compression strength UCS from 0.43 MPa to 2.6 MPa at a 28-day curing period. Also, the results showed that adding 25% of RAP to the soil- 20% CKD mixture increased the UCS value to 5.3 MPa after 28 days of the curing period. The final results showed that the optimum contents of CKD and RAP added to the cohesive soil were 20% and 25%, respectively, while the optimum curing period was 28 days