Field Density Testing in Pomona: Reliable Sand Cone Method

The sand cone method is ideal for near-surface tests, typically within the upper 12 inches of a compacted lift. For deeper verification, the test hole can be carefully extended, but the method becomes less practical below about 18 inches because of the difficulty in excavating a clean hole and recovering all loose material. In those cases, we coordinate with the contractor to perform tests as each lift is placed.

For projects in Pomona, individual sand cone field density tests typically range from US$110 to US$140 per test location, depending on the number of tests scheduled per mobilization and the accessibility of the site. A minimum mobilization fee may apply for very small projects. We provide a firm quote after reviewing the compaction specifications and the project's test frequency table.

The sand cone is a direct physical measurement of volume and mass, making it immune to the material composition errors that can affect nuclear gauges in soils with high mica, iron, or organic content. While slower than a nuclear gauge, it serves as the referee method and is required for calibration checks of nuclear equipment. In Pomona's variable fills, we often recommend sand cone testing for the first several lifts to validate the nuclear gauge readings before switching over.

For a typical single-family home foundation pad in Pomona, the geotechnical engineer usually specifies a minimum of one field density test per lift per 2,000 ft² of building area, with at least four tests across the pad for smaller footprints. For trench backfill around the foundation perimeter, the frequency typically increases to one test per 50 linear feet of trench per lift. We always follow the project's approved soils report frequency.