Analysis of Overturning Stability for Broken Back Retaining Wall by Considering the Second Failure Surface of Backfill

摘要

In the traditional analysis of overturning stability for broken back retaining wall, pressures acting on the upper and the lower parts of wall are calculated independently based on the hypotheses that earth pressure is linear distribution, and its resultant thrust is the vector sum of the pressures acting on the two parts; The existence of the second failure surface of backfill is judged by the formula of the critical angle for wall with gentle back as derived from Rankine theory. Not only this method is complicated, but also the relevant calculating results are tend to be unsafe Therefore, aiming at these problems, formulas for calculating the pressure on the second failure surface and the safety factor against overturning were derived by the horizontal differential element method considering the occurrence of the second failure surface. Then the traditional methods and the proposed one were compared by case studies. The results show that it is unsafe to design broken back retaining wall by these traditional methods and the critical angle formula for wall with gentle back is not suit for broken back retaining wall.