Retaining Walls Failure Essay

Retaining walls failures by earthquakes fall into two main categories. The first failure mode is by the wall itself sliding away from the back fill. The second failure consists of more than one action, or combined action, by sliding and rocking displacements or during an earthquake. During an earthquake, soil is displaced vertically and laterally due to a sudden release of energy, the cause of earthquakes. In area where seismic activity is readily occurring, the retaining wall must account for these displacements, in addition with the typical requirements. These requirements consist of a factory of safety against failure in bearing, sliding, and overturning.

In geologic terms, secondary effects from earthquakes refer shaking that occur from

The Ji-Ji (or Chi- Chi) Earthquake was an earthquake that occurred along the Chelungpu Fault in central Taiwan. The earthquake recorded a magnitude of 7.3 on the Richter scale which classifies the event as a major earthquake. The earthquake caused 2,415 casualties and injured over 11,000 people. It also caused significant damage to the area amounting to over 10 billion U.S. dollars. The aftermath included the destruction of major building, schools, and even affects soil reinforced soils. Among the damages caused by the earthquakes were many reinforced retaining walls. Everything was destroyed. A group of civil engineers took advantage if this disaster to investigate the geosynethic retaining walls used in Taiwan. The investigation included a total of 6 retaining structures, four modular-block reinforced soil retaining walls two rein enforced slopes that were relatively close to the fault like and received great damage (Linga. and Leshchinsky

This wall failed in a different, more conventional way. Two cracks were formed at the crest of the wall, 0.5 meters from the block and two meters form the blocks. This caused the blocks to move roughly 30 centimeters from the backfill. This caused a failure in the bottom corner of the wall and eventually backfill went through the wall. Geogrids and pins were used to connect the modular blocks. The first crack corresponds to length of the geo soil (Linga et al. 2007).

After reviewing the earthquake that occurred in Taiwan and a few of the failing retaining walls, a few questions can be asked about the failure modes. Were there any repetitions in failure modes? Was each retaining wall designed to withstand a seismic event? Finally, did the geosyenthic or pin connections cause any failures? If so, could a different connection or type of synthetic be used instead? From these questions, the engineers at Stratton Oakmont are working on new retaining walls to withstand earthquakes of all