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|Title:||GROUP EFFECT ON VERTICALLY LOADED MODEL PILES IN CLAY MEDIUM|
|Authors:||Jain, Nirmal Kumar|
|Keywords:||CIVIL ENGINEERING;VERTICALLY LOADED;PILES;CLAY MEDIUM|
|Abstract:||Piles are used as foundations to transmit loads from the superstructure through weak or unsuitable soils, water or air to a lower stratum that have sufficient value to bear these loads. The piles are generally driven in groups. The pile groups are subjected to vertical loads due to dead and live loads of the superstructure. The safety of structure depends upon the ability of the supporting piles to transmit these loads to soils of adequate bearing capacity. An experimental investigation was performed on 9.0 mm outer diameter and 5.9 mm inner diameter aluminium pipe piles in a homogeneous clay to determine the relation between the behaviour of isolated single piles and similar piles placed in a group. Tests were made using piles with embeded lengths of 30 diameters in square groups of 2x2 and 3x3 as piled foundation and as free standing pile groups. The centre to centre distance between the piles in the group was varied as 2d, 3d, 4d, 6d, and 8d, were d is the diameter of the pile. A 55x55x60 ams. wooden tank.was filled with clay and the pile group was driven in it along with the single piles. Wooden tank filled with clay was covered with a thick layer of grease on the surface. This prevented movement of moisture from the soil. The single piles and group were tested after allowing for thixotropic hardening of the soil for 24 hours. Two single piles were tested with each gasoup for comparison. (x) The study indicates the following behaviour of the pile groups with respect to the spacing and number of piles. (a) A good reproducibility of tests can be obtained by following the procedure adopted in the present investigation. (b) For each group there exists a centre to centre spacing of piles which will give a peak value of the pile group load; beyond which the increase in spacing does not result in the increase of efficiency at the same rate. It has found that the pile group load increases as the size and number of piles in a group are increased. (d) In piled foundation the efficiency is greater than 10C% and it reaches to about 2240 at the optimum spacing. This indicates that the load carrying capacity of the single pile in a group is 2.2 times that of an isolated pile placed under similar conditions, (e) In free standing groups the efficiency reaches to 71% at the optimum spacing. This indicates that in all cases the average load per pile in a group is less than that of an isolated single pile under similar conditions. (f) Comparison of the results of piled foundation and free standing pile groups indicates, that considerable part of the load is shared by the pile cap which rests on the soil.|
|Research Supervisor/ Guide:||Ranjan, Gopal|
|Appears in Collections:||MASTERS' DISSERTATIONS (Civil Engg)|
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