Discussion of dislocation phenomena of resistance and load in formula for stability safety factor
摘要
The stability safety factor of geotechnical structure shall be the sum of resistance divided by the sum of loads. There are five kinds of dislocation phenomena between resistance and load in the formula for calculating the stability safety factor in the worldwide relevant standards, and they are inconsistent with the definition of safety factor. (1) The anti-sliding force produced by some soil strips in the slice method is included in the denominator, and the first type of dislocation will be formed if it minuses the sliding force. The second type of dislocation will be formed if it pluses the sliding force. If the tangential component of anchor resistance is placed in the denominator to minus the sliding force, the first type of dislocation will be formed as well. (2) The third type of dislocation will be formed if water pressures and other pressures are placed in the numerator and subtracted from the resistance, and when the third type works together with the first and second types respectively, they result in the fourth and fifth types. (3) The first and third types result in a virtual height of safety factor calculation, which leads to insufficient safety in engineering sometimes. The second type results in a virtual lower safety factor, which may lead to great waste. The fourth and fifth types increase the uncertainty of calculated results, and the fourth kind will further cause the virtual height of safety factor. (4) These dislocated formulas can be modified and generalized into a unified formula.