Several foundation techniques, such as belled piers, under-reamed piles, helical piles are adopted in expansive soils to avoid the problem posed by its swelling nature. In recent years, the granular pile anchor (GPA) technique has been in practice for resisting the uplift of foundation caused by expansive clay beds. Model and prototype studies on GPA revealed that swelling of expansive clay beds can be effectively controlled by the GPA technique. This paper presents a comparative study on the behaviour of GPA and helical pile anchors (HPAs) in expansive soil subjected to swelling. The data presented in this paper pertain to model tests of clay beds reinforced with varying number of GPAs (N = 0, 1, 2 and 3). Similarly, the model tests were conducted on clay bed reinforced with varying number of HPAs (N = 0, 1, 2 and 3). Tests were also conducted by varying the number of helix. Test results shows that the heave (mm) decreases with an increase in the number of GPAs. Similarly, the heave decreases with an increase in the number of HPA. Further, heave (mm) also decreased with increase in the number of helix. The resultant heave reduction is found to be more in case of expansive soil reinforced with GPA when compared to expansive soil reinforced with helical pile.

Offshore wind energy development is driven by ongoing research and development to determine technological issues connected with offshore wind turbines. A fundamental design difficulty is the offshore wind turbine foundations. By far, one of the most commonly practiced foundation systems is mono helical pile foundations because of their simplicity and resilience. Most of the studies on mono helical piles were focused on granular soils and few studies were on clayey soils. However, mono helical piles in clayey soils under combined loading remain to be examined. Hence, a series of three-dimensional finite element analyses were carried out to predict the uplift and lateral capacity of the helical pile embedded in soft clay. The numerical model is verified using the results from the analytical results and a small-scale laboratory test. The verified model is used to simulate the helical pile behavior under the combined uplift and lateral loading condition considering the pile with a different number of helical plates. The results of the combined loading analyses reveal that the lateral capacity decreased when the pile was subjected to uplift load, and a maximum reduction of 12% is observed in mono helical piles provided with a single plate for an applied 50% of the ultimate uplift load. The influence of uplift load also increased the bending moment of the helical pile. Finally, it is suggested that the helical piles should be designed considering the aspects for combined loading conditions.

Human activity inevitably produces waste materials that must be managed. Some waste can be reused. However many wastes that cannot be used beneficially must be disposed of ensuring environmental safety. One of the common methods of disposal is landfilling. The most common problems of the landfill site are environmental degradation and groundwater contamination caused by leachate produced during the decomposition process of organic material and rainfall. Liner in a landfill is an important component which prevent leachate migration and prevent groundwater contamination. Earthen liners have been widely used to contain waste materials in landfill. Liners and covers for municipal and hazardous waste containment facilities are often constructed with the use of fine-grained, low plasticity soils. Because of low permeability geosynthetic clay liners and compacted clay liners are the main materials used in waste disposal landfills. This paper summaries the important geotechnical characteristics such as hydraulic conductivity, liquid limit and free swell index of geosynthetic clay liner and compacted clay liner based on research findings. This paper also compares geosynthetic clay liner and compacted clay liner based on certain criteria such as thickness, availability of materials, vulnerability to damage etc.