This research describes the seepage characteristics of experimental model test of dam with cutoff located at different region (at dam heel, at mid floor of dam, and at dam toe). It is resting on sandy soil with cavity at different locations in X and Y directions (such as in Al-Najaf soil city). Thirty three model tests are performed in laboratory by using steel box to estimate the quantity of the seepage and flow lines direction. It was concluded that the best location of the cutoff wall is at the dam toe for model test with cavity (Xc B = 0 and 0.5), but for model test with cavity (Xc B ≥1), the best location of the sheet pile wall becomes at the dam heel. For negative location of the cavity, the best location of the sheet pile wall is at the middle of the floor dam.

Anchor systems have been widely used recently due to its importance in increasing the stability of structures subjected to uplift forces and overturning moments. Accordingly, it is vital to investigate the parameters that might affect anchor systems’ operational performance and structural behavior. The current study investigates the characteristics and parameters that might affect the uplift capacity of a horizontal anchor plate embedded in cohesionless soil. The sample of soil was brought from Al-Najaf province (Iraq). The parameters included are; plate embedding depth, the soil’s effective dimension above the plate, and soil improvement by compaction. The model setup includes forming a steel container with dimensions (70 x 70 x 70) cm and a circular steel plate of 10 cm diameter. Three embedding depth ratios were chosen; these are 0.1, 0.2, and 0.3 of the total soil sample depth. Three effective soil diameters were chosen as percentages of the plate diameter; these are 1.0%, 1.5%, and 3%. According to the ASTM specification, several physical and chemical tests were carried out on the soil sample to determine its classification and needed engineering characteristics. The laboratory test results revealed that for both treated and untreated soil samples, the ultimate uplift capacity of the anchor plate increases with increasing the embedded depth of the anchor plate; for example, at improvement ratio (D/d=3.0), the ratio (P/Po = 1.05,1.28 and 1.6) for depth ratio (h/T=0.1,0.2, and 0.3) respectively. The values of the pull-out capacity of the anchor plate are increased with increasing the improvement area above the anchor plate; for example, at depth ratio (h/T=0.3), the values P/Po = 1.05,1.28 and 1.6 for D/d=1,1.5 and 3.0) respectively. Finally, the compaction technique can effectively improve the behavior of the anchor plate.

Cavities formation into soil media is a very common problem that occurs in the gypseous soils (in which the gypsum content equals 2% and more). The gypsum dissolves by water flow leaching and leaves cavities in different shapes and sizes. In slab on grade system, the American concrete institute (ACI 360) recommends, the concrete slab transforms the load to the ground by about less than 50% of the allowable bearing capacity thereof, but when the soil contains cavities and excavation, the concrete slab behavior will change. In order to investigate the changing in behavior, twelve concrete slabs were prepared and tested on a soil media contains cavities. The investigated parameters were: cavity depth, steel wire reinforcement existence, bearing load plate shapes, and the load distributed parallel or perpendicular to the cavity. From the experimental results, it has been concluded that, the plain and reinforced concrete slab capacity decreases by (30.7%) and (7.4%) when a cylindrical continuous cavity forms at (30% mm) depth from the soil surface. However, when the cavity forms at a distance equal to (15%) from the soil surface, the plain and reinforced concrete slab capacity reduced by (70%) and (61%) respectively.

The stabilization of an anchoring system plays a significant role in geotechnical engineering structures. To develop a clear understanding of the vertical plate anchors behavior due to geogrid reinforced soil under various pullout load inclination ranging from (0, 25, 45, 60, and 90) degrees in Cohesionless soil, a series of total (34) tests were carried out. The soil has been investigated by using small-scale model tests. Geogrid with different width and heights placed (vertically or horizontally in front of the vertical anchor plate at different locations were used to reinforce a soil mass in front of square anchor plates. The studied parameters include reinforced soil mass width, soil mass height, the location of geogrid-reinforced soil mass, effect of water content increase, and the inclination angle of pullout load. The test results indicate that Geogrid reinforced mass in front of a vertical anchor plate significantly increases the stiffness of the soil and increases the pullout resistance of shallow anchor plates. According to test outcomes, critical situations also were stated and discussed.

Many reasons deform the cavity inside the soil. The reasons can be classified to two main reasons natural and artificial reasons. Natural reasons belong to the type of soil (It is usually due to materials that enter the formation of the soil and may be affected by natural factors). And artificial reasons due to human work inside the ground like old buildings. The size of these cavities effect on the capacity on structures and it can cause huge damages for the structures. Experimental study presents the effect of size of cavity on the capacity of the plate anchor. A scale model anchor plate embedded inside sandy soil in laboratory to study the behavior of it under the effect of three types of cavities with dimeter (10,15 and 20) cm. the results show direct effect on the capacity of plate anchor and the type of failure that deform inside the soil to resist the uplift loads.