Seismic Damage Assessment of Gravity Retaining Walls Based on Grey Correlation and Fuzzy Mathematics

Strong earthquake shaking in the Longmen Mountain area in 2008 led to severe damage to many retaining structures. How to assess damaged retaining walls in the earthquake zone was a problem that required an urgent solution. This paper summarizes five types of retaining-wall failure modes through analysis of earthquake damage in the research area, including sliding failure, settlement failure, toppling failure, material failure, and overtopping failure. Then the factors influencing seismic safety evaluations were qualitatively analysed and classified on the basis of comprehensive principles, important principles and scientific principles. Along with the failure modes of retaining walls, we also examined the critical factors and some general factors. We took a value of 60 % damage to be a critical factor, and the general factors divided into two levels, and 10 indexes: the sliding distance, the settlement depth, the inclination angle, the number of cracks, the ratio of crack length and the retaining wall length, the ratio of crack depth and the retaining wall thickness, the crack width, the dislocation distance, the range of retaining wall collapse, and the coverage of rock and soil on the retaining wall. The seismic safety evaluation system for retaining walls was built by grey correlation analysis and fuzzy mathematic theory. Its use can allow prevention to replace repair and can aid post-earthquake recovery and reconstruction.