The process of boring a hole for a pile seriously disturbs the clay in the neighborhood of the hole. Placing the concrete causes water to be absorbed by the clay surrounding the pile, leading to softening and reduced strength. The resistance of the pile is calculated by the relations: ———- (1) And ———- (2) Where w is 0.8 for B less than 1 m and 0.75 for B greater than 1 m. The Working load for the pile is given by: for plain shafts ————- (3) For…
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Driven Pile in Stiff Clay, soft Clay, Very Soft Clay
When piles are driven in cohesive soil, the shear strength is changed radically due to occurrence of following phenomena. Remolding Ground heave Formation of an enlarged hole Strain softening Remolding – Pile driving disturbs soil fabrics. This depends on sensitivity soils. With passage of time, the shear strength is regained due to the property called thixotropy. Soft sensitive soils regain their strength fully. After thirty days of driving about 75 % of strength is regained. Ground Heave – When a pile is driven in clay pore water pressure is developed…
Read MoreLoad Carrying Capacity Pile
There are various methods of determining the load carrying capacity of single piles. They are: By Static Bearing Capacity Equations Based on SPT Results Based on CPT Results By Pile Driving Formula By Pile Loading Tests Static Bearing Capacity Equations The static methods give the ultimate bearing capacity of an individual pile, depending upon the characteristics of soil. Assume a pile of diameter D is driven to a length L from the ground surface as shown in Fig.1. Let Qu be the net load applied at the head of the…
Read MoreBehavior of Single Pile and Pile Group Under loads
Behavior of Single pile Under Load Figure 1 shows a load settlement curve for a pile driven into a uniform soil. At early stages of loading the settlement is very small. The settlement at this stage is wholly elastic due to elastic deformation of pile and surrounding soil. When the pile is unloaded the deformation is almost wholly recovered as shown in Fig.1 (a). Strain gages attached along the pile shaft and base indicate that at small loads the pile shaft takes all the applied loads by friction developed between…
Read MorePiling Hammer | Types of piling hammer
Piles are driven into the ground by means of hammer. Piling Hammer are classified into following types as shown in Fig.1 Drop hammer Single acting hammer Double acting hammer Diesel hammer Vibratory hammer Drop hammer – A drop hammer is lifted up by rope and dropped freely on the pile head. During the driving operation, a cap is fixed to the top of the pile and a cushion is provided in between the pile and the cap. Single acting hammer – In a single acting hammer, a hammer is lifted…
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