Industry Case Study: Amazon Warehouse Down in Phoenix, AZ
Challenge
Situation: Amazon Warehouse is one of five delivery stations located off University and 24th Street. It is estimated that Amazon employs approximately 17,500 full-time and part-time employees in Arizona, making it among the largest employers in the state. There are plans to hire about 500 people for the new building that is being built near Mill Avenue and Rio Salado Parkway in the near future. However, there was an important foundation problem that did not let the whole organization stay with peace of mind.
Challenges: A substantial sinkhole had emerged within a retention area near a retaining wall. Enamul Hoque, Geotechnical Engineer, designed a repair plan to fill the sinkhole and create a grout wall extending away from the sinkhole to stabilize the surrounding soils. The grout wall was created by compaction grouting additional holes that were drilled to 40' depth. The sinkhole was filled with 17 yards of grout material, while the adjacent 14 holes took 70 yards of grout material.
Solution
Solution: Sub-surface soils were stabilized, mitigating the likelihood of an additional sinkhole. The grout wall protected the footing of the retaining wall from being undermined. The stabilization of the sub-surface soils prevents further erosion of the soil, which is a key factor in mitigating the likelihood of a sinkhole developing. Grout walls help to provide a supportive footing for the retaining wall and protect the structure from the potential of being undermined by soil erosion.
Conclusion: The repair plan was successful in stabilizing the area and preventing further sinkhole formation. The grout wall created a barrier that redirected groundwater flow away from the sinkhole and prevented further soil erosion. The additional grout material filled the sinkhole and prevented further collapse. The backfill material and geotextile fabric also helped to reduce water infiltration, which further stabilized the area. Finally, the seeding and compaction of the remaining soil provided additional stabilization to the area and ensured that the repair was successful.