A three-dimensional finite elements limit analysis (FELA) has been performed to assess the stability of a vertical excavation supported by a contiguous piled wall in a soft cohesive-frictional soil mass. The pile has been embedded to a depth D below the base of an excavation which is having height H. The value of the maximum soil unit weight ( \({\upgamma }_{\text{cr}}),\) which induces the failure of the excavation supported by piles, has been computed. For a given diameter (d) of the pile, several combinations of clear spacing (s) between the piles, pile-soil interface roughness factor (m), and the shear strength material parameters ( \(c,\upvarphi\) ) of the soil mass have been chosen to compute the stability number ( \(\upgamma\) cr H/c). For simulating the problem with the limiting case of \(\frac{s}{d} = 0,\) a plane strain analysis has also been carried out for an excavation supported by a continuous wall, having thickness d, to determine the corresponding solution with a given D/H. The stability number for a contiguous piled wall increases continuously with (i) a decrease in the spacing to diameter ratio (s/d) of the pile, (ii) an increase in D/H, (ii) an increase in the friction angle ( \(\upvarphi\) ) of the soil, and (iii) an increase in the interface roughness factor (m) of the pile-soil interface. The computational results provided herein will be useful for designing a contiguous piled wall.
