MSE Retaining Walls, Importance of Quality Construction and Engineering Oversight

摘要

The authors have been retained to investigate the cause of distress to several MSE retaining walls used in residential developments throughout Colorado. These walls were constructed using segmental retaining blocks. The manifestation of distress observed during our investigations included crest toppling, face bulging, block deterioration, and lateral deflection of the walls. The investigations of the causes of distress involved the review of the original design and intrusive investigation of the walls. The intrusive investigations of the walls included the advancement of geotechnical borings and removal of selected sections of the wall to observe how the walls were constructed. The results of the investigations indicated that while the causes of the observed distress included construction without an engineered wall, poor wall designs, and poor block manufacturing, a main contributor to wall distress was poor construction practices and poor construction oversight. The poor construction practices observed included the use of geosynthetics that were different than those specified in the design plans, improper spacing of the geosynthetics, improper orientation of the geosynthetics, and improper length of the geosynthetics. These observations, along with other deviations from the design during construction, indicate that selection of a quality contractor and proper engineering oversight during construction may be as important as providing quality designs in ensuring quality performance of the walls.