2.4 Allowable bearing capacity of shallow foundations When the stresses in point M reach the limiting equilibrium,o and o3 at failure are related by the following expression from Mohr-Coulomb failure criteria (当M点达到极限平衡状态时，大小主应力必需满足以 下公式) =a5+2如m5号》 z is depth of the plastic zone and is expressed as a function of B(z为塑性区深度，是β的函数) z=9-Yd sin2B --d Y·π sinφ y.tanΦ 2.4 Allowable bearing capacity of shallow foundations ▪ When the stresses in point M reach the limiting equilibrium, 1 and 3 at failure are related by the following expression from Mohr-Coulomb failure criteria (当M点达到极限平衡状态时,大小主应力必需满足以 下公式)         +   +        =    + 2 2c tan 45 2 tan 45 2 1 3 d tan c 2 sin q d sin 2 z −    −        − b  b   −   = ▪ z is depth of the plastic zone and is expressed as a function of b (z为塑性区深度,是b的函数)