Shot‐Rock Fill Construction: Case History

Construction of an automobile assembly plant with 3,000,000‐sq ft $(280\text{,}000‐m^2)$ plan area required excavation of more than 2,700,000 cu yd $\left(2\text{,}000\text{,}000m^3\right)$ of soil and rock, and placement of more than 1,700,000 cu yd $\left(1\text{,}300\text{,}000m^3\right)$ of fill. Footings on rock and piers drilled through soil‐rock fill were used to support column loads. Shale‐limestone bedrock was excavated by blasting. Processed rock yielded sufficient fines to provide some cohesion to the fill. Fill performance was evaluated by field plate loading tests. Settlements of fill and underlying residual soils were monitored during construction. Construction was completed successfully within a compressed schedule. Plate load tests provided important data on soil‐rock fill compressibility. Settlement readings confirmed laboratory and field test results, and verified predictions of settlement magnitude. Rate of settlement greatly exceeded estimated rates. Pier drilling through the soil‐rock fill was accomplished without liners, with no significant ravelling of fill material.