BEHAVIOUR OF LIME CONCRETE PILES BASED ON EXPERIMENTAL & FINITE ELEMENT ANALYSIS

Abstract

With the growing population of world and day by day increases in living standards, people face many problems related to soil. Soil may or may not be the strong enough to withstand the loads coming from above structures, resulting in not only human losses but also a large capital loss. To overcome these issues of problematic soil many procedures/methods are used and these soft problematic soils are reclaimed. Main issues encountered in soft soils are low bearing capacity, high compressibility, low shear strength, more settlement, swelling and shrinkage. Lime concrete piles may also b used to improve these soft soils. Lime concrete piles are mixture of quick lime, sand and crush by some ratio. Lime concrete piles increase bearing capacity of soil bt reducing water content, reducing settlement, increasing rate if consolidation and increasing permeability of soil. Due to chemical bonding lime concrete pile act as e strong vertical compression members thereby improving the bearing capacity of soil. In this study, detailed field and experimental investigation on behavior of single as well as group of 3 lime concrete piles is constructed by varying its factors in laboratory as shear strength of clayey soil, diameter, spacing between the piles and loading conditions. Laboratory testing is carried out on single pile area to check its axial capacity and entire area loading to check its overall capacity. Group of pile setup is used to check its actual bearing capacity measurement and variation due to varying parameters. Finite Element method analysis is also being carried out with software PLAXIS-2D using 15 nodes triangular element. Axially symmetric drained conditions for piling material and undrained condition for soil are used for Mohr Columb’s criterion based analysis. The results obtained in field, laboratory and FEM shows good improvement. Results indicate that field represents 70 % improvement, calculated improvement from laboratory experiments is 183% viii while FEM analysis comparison of treated and untreated soil samples show % improvement. It is concluded that more improvement is achieved at higher shear strength as compared to lesser shear strength of soil. Lime concrete piles are more feasible or beneficial at lower L/D ratios. As observed in our case as the L/D ratio increased from 4 to 7 the bearing capacity of soil decreased from 37% to 12%. The effect is because of bulging of Lime concrete piles in composite ground, therefore the penetration length of pile is observed to be 4 times its diameter. It was observed that as the spacing between the piles is increased in triangular pattern the bearing capacity was reduced. Bulging effect of lime concrete piles was observed in upper portion of lime concrete piles when alone pile was loaded. Whereas no bulging in pile was observed when entire equivalent area was loaded. In entire area loaded experiments the capacity failure was there.