07/15/2004 Env Bd Packet - Laserfiche WebLink

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STS Sampling Procedures g_40 Auger Sampling (AS) In this procedure, soil samples are collected from cuttings off of the auger flights as they are removed from the ground. The samples are typically retained in sealed jars or plastic bags, then shipped to a laboratory for further examination and testing. Such samples provide a general indication of subsurface conditions; however, they do not provide undisturbed samples, nor do they provide samples from discrete depths. Split- barrel Sampling (SS) - (ASTM Standard D -1586) In the split - barrel sampling procedure, a 1.375 -inch I.D. , 2 -inch O.D., split barrel sampler is driven into the soil a distance of 18 inches by means of a 140 pound hammer falling 30 inches. The value of the Standard Penetration Resistance, N, is obtained by counting the number of blows of the hammer over the final 12 inches of driving. This value provides a qualitative indication of the in- place relative density of cohesionless soils and consistency of cohesive soils. The indication is qualitative only, because many factors such as soil composition, gravel and cobble content, type of hammer, sample depth and groundwater seepage pressure can significantly affect the Standard Penetration Resistance N Value. Results in similar soils obtained by drill crews using different rigs, drilling procedures, and hammer - rod -spoon assemblies may not correlate directly. A representative portion of the recovered sample is placed in a sample jar, labeled and then shipped to a laboratory for further analysis and testing. Shelby Tube Sampling Procedure (ST) - (ASTM Standard D -1587) In the Shelby tube sampling procedure, a thin - walled steel seamless tube with a beveled cutting edge is pushed hydraulically into the soil and then pulled to obtain a relatively undisturbed sample. This procedure is typically used to sample firm to hard cohesive soils. Two -inch diameter tubes are generally utilized. Three -inch diameter tubes are occasionally utilized to sample softer soils where minimally disturbed samples are desired. The tubes are sealed, labeled, and then shipped to a laboratory for extrusion, further analysis and testing. Bulk Sample (BS) Bulk samples are typically obtained by hand tool digging into soil or rock deposits that are exposed at the ground surface or within an excavation (walls or bottom). Bulk samples are typically retained in sealed jars or plastic bags. Continuous Sample Tube (CS) This type of sampling device consists of 5 -ft. sections of thin -wall tubes or split - barrel pipes which are capable of retrieving continuous columns of soil in 5 -ft. maximum increments. Because of a continuous slot in the sampling tubes, the sampler allows field determination of stratification boundaries and containerization of soil samples from any sampling depth within the 5 -ft. interval. This sampler is used inside a hollow -stem auger and is advanced slightly ahead of the auger head as the, auger is turned into the soil. Split- barrel samples are typically opened in the field. Recovered soil is logged and representative samples retained in sealed jars. Tube samples are sealed, labeled and shipped to a laboratory for extrusion and testing.