Failure Mechanism Analysis of Reinforced Foundation from Experimental and Numerical Simulations

Geogrid has been extensively used in engineering practice as a horizontal reinforcing material to improve the performance of foundations, embankments, and road base systems. This paper presented the results of laboratory static load tests on transparent soil foundations reinforced with biaxial polylactic acid geogrid and studied the reinforcement mechanism and foundation failure mode of the reinforced foundation. The different load settlement behaviour between reinforced foundations with different reinforcement layer numbers was studied by varying the number of geogrid layers. The deformation of reinforcements and foundation soil was recorded with an industrial camera. The strain of the reinforcements was monitored by Fiber Bragg Grating (FBG) sensors. In addition, a two-dimensional discrete element model was established based on the model tests to analyse the load transfer behaviour and deformation law of the reinforced foundation. The results indicated that geogrid can effectively improve the bearing capacity of the foundation. As the number of reinforcement layers increases, the improving effect is more significant. The reinforced soil can provide a stronger upward resistance than unreinforced soil by activating the tensile force of the geogrid. The simulation results present the load transfer behaviour and reinforcement mechanism of geogrid. With the increase of reinforcement layers, the position of the sliding surface moves downward, and the area of the sliding surface increases. Geogrid can limit soil displacement and delay the development of the sliding surface.