INTERACTION OF A PROTECTING WALL WITH A SOIL MASSIF IN PROCESS EXTRACTIONS OF FOUNDATION PIT Abu Mahadi Mohamed Ibrahim, V.I. Elfimov Department of Building Structures and Constructions Engineering faculty Peoples Friendship University of Russia Mikluha-Maklay str., 6, Moscow, Russia, 117198 The computing procedure to determine the soil pressure on retaining structure and it’s displacements during earth excavation from a pit is developed. <...> At the first stage the protecting construction (slurry wall, sheet piling, row of piles) is enclosed in a ground from the both sides, then the earth excavation from one side of the screen begins. <...> The variations of soil pressure on the both sides of protecting screen are traced in the process of computing with proposed method. <...> The retaining structure in the calculating scheme is simulated as an elastic beam construction. <...> The soil is presented as a nonlinear model, in which the modulus of rigidity decreases when the soil stress is nearing to the ultimate limit value. <...> The mathematical procedure consists of iteration of sequential separate calculations by Gauss’s method. <...> The protecting construction is considered as flexible (yielding) beam or beam plate, which is conditionally divided into unit plots or elements a1, a2, . an (fig. 1). 109 Вестник РУДН, серия Инженерные исследования, 2013, № 1 Qb1 0 c h Mb1 P1 P2 P3 R1 R2 R3 1 Rn-L l1 z Fig. 1. <...> Key diagram of flexible retaining wall Each element of a beam is considered as a final element subjected to bending by the moments Mb, Me and the transversal forces Qb, Qe applied at the beginning and extremity of an element (fig. 2). <...> The relations between the beam sag S, deflection angle of it’s cross-section ϕ and inner forces are expressed by the known formulas: ϕ = –S ′, M = –GS ′′, Q = –GS ′′′, (1) where G = EJ — flexural rigidity of a beam; E — elasticity modulus of a beam material; J — moment of inertia of the beam cross-section; the primes mean derivation with respect to x; x — centerline of a beam element directed from the beginning of an element to its extremity. 110 pn d an P4 P5 P6 2 a4 H d d d d a1 <...>