2.4 Allowable bearing capacity of shallow foundations From elastic theory,the increases in principal stresses at a given point M are shown as follows(地基中任意点M的 附加大，小主应力可从弹性理论找出) -dB+sin2B) Ac3=9-Y:d(2B-sin2B) 元 元 03 2.4 Allowable bearing capacity of shallow foundations ▪ From elastic theory, the increases in principal stresses at a given point M are shown as follows (地基中任意点M的 附加大,小主应力可从弹性理论找出) b x z z 2b q 1 3 x qo=  d M ( b + b)  −    = 2 sin 2 q d 1 ( b − b)  −    = 2 sin 2 q d 3