Model Tests of Reinforced Foundation Based on Transparent Soil Technique

Abstract:

Five groups of model tests of reinforced foundation with different reinforcement lengths and depths (layer numbers) as well as 1 group of model test of unreinforced foundation were carried out by transparent technique. The evolution of displacement field in the reinforced foundation and procedure of slide failure under strip loading were investigated. The loadsettlement characteristic of reinforced foundation was also discussed. The results show that during the settlement of trip footing, horizontal displacement accumulates first in the unreinforced zone near the lower right and the left corner of the reinforced zone, and then extends upward to reinforcement layers, which causes the tensile failure of the reinforcements successively from bottom to top and at last forms micro shear failure surface. Two stress diffusion zones are formed during the settlement of the strip footing. The two zones extend downward along the bend section of each reinforcement layers and the strip footing edges, respectively. The stress diffusion angle along the bend section is 2.5 times of that along the trip footing edges. Both of reinforced and unreinforced foundations fail in Prandtl slide mode. The depth and width of the slip surfaces increase with an increase of reinforced depth and reinforcement length. When the strength of reinforcements is deficient, extending reinforcements has little effect on the bearing capacity of the reinforced foundation, whereas the increasing reinforcement layers can significantly affect the bearing capacity.

Key words:reinforced foundation; transparent soil; bearing capacity; displacement field; failure mode