K_0≠1时的地基临塑载荷和临界载荷近似计算公式

Approximate formulas of critical edge pressure and critical load of subsoil with K_0≠1

地基弹塑性承载力pcr、p1/4的公式在推导过程中,为方便求解,一般假设地基土体的静止土压力系数K0=1,即把自重应力场看成是静水应力。这一假定实际上人为地增加了地基土的侧向压力,使土体处于加密状态,从而过高地估计了地基承载力。考虑K0≠1的前提下,由地基土中一点的应力状态,根据莫尔-库伦破坏准则,得到该点的临塑、临界荷载的近似公式。该公式修正了一些学者在K0≠1时推导地基弹塑性承载力公式过程中的缺陷,也弥补了现有公式的局限性,得到了土体抗剪强度参数c、φ在不同的K0下对地基临界载荷p1/4的影响,给出了该近似公式的适用条件。

When it proposes calculation formulas of critical edge pressure Pcr of subsoil and critical load P1/4, coefficient of earth pressure at rest K0 equals to 1. It means that the field of geostatie stress equal to hydrostatic state stress. This supposal inereases the lateral load of subsoil, and makes the subsoil be in intensive state, that results in a higher bearing capacity of subsoil. Determining the stress state of one point in subsoil, then proposing approximate formulas of subsoil critical edge pressure and eritieal load when K0 ≠1 based on Mohr-Coulomb criterion. This method corrects some calculating mistakes when it proposes calculation formulas of subsoil bearing eapacity which obtains K0≠1 by some scholars. And it compensates the limitation of some other calculation formulas. The influence of shear strength indexes on critical load of subsoil is found. Conditions which are applicable to the approximate formula are given.