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Enviro-Core Displacement Sample barrel Sample watersamples Small-diameter quickly point removed. lowered to barrel and are collected piezometers or advanced tog from inside monitorin Drive casing bottom o1 drive drive casing g ,sampling left in soil to casing. advanced 3 drive casing points are depth. prevent feel.Soil with a installed prior to Displacement sloughing and samples peristaltic withdrawing point prevents cross- collected in pump,small- drive casing soil from contamination. sample diameter entering drive barrel. bailer,or bladder pump casing Figure 2- Typical Soil and Groundwater Sampling Sequence The inner barrel and drive casing are advanced into the ground turn, required a faster way to withdraw the sample barrel (or simultaneously, requiring an effective means of coupling the displacement point) from the drive casing. An inflatable inner barrel with the outer drive casing. This is achieved in one packer, commonly used to seal boreholes during hydraulic of two ways. The first method, referred to as the internal rod testing, was modified to provide a means of connecting the method, uses internal steel rods to keep the inner sample barrel sample barrel to the drive casing (Figure 3). With this method, seated against the drive shoe(Figure 1). The internal rods the sample barrel is coupled to the inflatable packer. The (three-foot sections of 1.38-inch-diameter steel sampling rods) packerfinner barrel assembly is quickly lowered to the bottom serve several purposes. First,they are used to lower the empty of the drive casing with a wireline. The shoulder in the drive inner barrel (or the displacement point) to the bottom of the shoe prevents the sample barrel from protruding beyond the steel-cased probe hole. Then,the rods are placed in compres- bottom of the drive casing. The packer is then inflated with sion inside of the drive casing by attaching the drive head. This compressed nitrogen, rigidly coupling the sample barrel to the keeps the bottom of the sample barrel (or displacement point) drive casing. The sample barrel and drive casing are then snug against the shoulder of the drive shoe. Finally, after the simultaneously advanced three feet,filling the sample liners three foot run is complete and the sample liners are full of soil, inside of the inner barrel with soil. The packer is then deflated, the inner barrel (containing the stainless steel sample liners and and the sample barrellpacker assembly is quickly removed soil) is retrieved by removing the internal rods- A typical soil from the boring with a winch. sampling sequence is shown in Figure 2. After the sample barrel has been retrieved, the sample finers While the internal rod method works well at shallow depths, are removed for chemical analysis or lithologic identification. If recent improvements in the methods used to advance the deeper soil cores are needed, a new three-foot sample barrel, Enviro-Core system have made it possible to advance the fitted with empty stainless steel finers or a clear plastic liner, is Enviro-Core system to depths greater than 100 feet. This, in quickly lowered to the bottom of the probe hole. The sample