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D6151 – Standard Test Method Technical Guide
Designation: D6151/D6151M −15 — Standard Practice for Using Hollow-Stem Augers for Geotechnical Exploration and Soil Sampling. This standard provides the authoritative framework for obtaining soil samples using Hollow-Stem Auger (HSA) systems, specifically focusing on geotechnical exploration and the retrieval of samples suitable for engineering properties testing.
📐 Scope and Core Methodology
The primary scope of D6151 is the standardization of HSA drilling practices for geotechnical work. It provides detailed instructions on advancing the augers, managing the drill string, and performing critical “hole preparation” steps required before any sampling event. The standard emphasizes that HSA drilling is an enabling technology, most often combined with other specific methods. These commonly include the Standard Penetration Test (Test Method D1586), Thin-Walled Tube Sampling (Practice D1587), and Ring-Lined Barrel Sampling (Practice D3550). The practice carefully delineates its own limitations; it explicitly excludes geoenvironmental site characterization and the installation of monitoring wells (which are covered under Guide D5784) and notes that alternative drilling methods are summarized in Guide D6286.
⚙️ Sampling Integration and Operational Protocols
The HSA acts as a temporary casing, providing stable access to the subsurface. The standard outlines the operational protocol for reaching the target depth, including the removal of the center bit or plug to allow tools to be lowered through the drill string. A significant emphasis is placed on drilling fluid management and borehole advancement rates to minimize soil disturbance below the auger bit face. Once the boring is prepared, standard sampling tools are deployed. The practice also notes that in-situ tests, such as the Vane Shear Test (Test Method D2573), can be performed at the base of the boring by accessing the soil directly through the open auger string.
⚡ Critical Field Application Warning: The standard mandates that all observed and calculated values must conform to the guidelines for significant digits and rounding established in Practice D6026. Improper handling of significant digits during the recording of blow counts or sample depths can lead to non-conformance with the entire standard.
📊 Regulatory Roles and Referenced Standards
Compliance with D6151 is heavily dependent on its supporting documents. The following table outlines the key ASTM standards directly integrated with the HSA practice as described in the scope. Furthermore, the standard requires the user to establish appropriate safety and health practices, adhering specifically to OSHA regulations, DCDMA safety manuals, and applicable state and local codes. Agency qualifications must align with the minimum requirements of Practice D3740.
| 🟦 Standard | 📏 Title / Designation | 🎯 Typical Role in HSA Practice |
|---|---|---|
| D1586 | Test Method for SPT | Obtaining disturbed samples & N-values for engineering estimates |
| D1587 | Practice for Thin-Wall Tube Sampling | Obtaining relatively undisturbed samples for lab strength/consolidation |
| D3550 | Practice for Ring-Lined Barrel Sampling | Obtaining undisturbed samples in cohesive soils |
| D2573 | Test Method for Vane Shear Test | Performing in-situ strength testing via the drill string |
| D5784 | Guide for Monitoring Well Install. | Explicitly excluded scope; referenced for geoenvironmental work |
| D6026 | Practice for Significant Digits | Mandatory protocol for all observed and calculated data |
| D1452 | Practice for Solid Stem Augers | Alternative drilling method described separately |
📌 Professional Judgment Note: The standard clearly states that it “cannot replace education or experience and should be used in conjunction with professional judgment.” It is a standardized framework for operation, not a substitute for site-specific geological knowledge or engineering analysis, as previously outlined in the withdrawn Guide D420.
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D6151?
The standard provides the specific practice for using Hollow-Stem Augers for geotechnical exploration and soil sampling. It focuses on preparing the borehole for combined sampling methods (like SPT and thin-wall tubes) to obtain samples suitable for engineering property testing.
💡 Can ASTM D6151 be used for installing groundwater monitoring wells?
No. The scope explicitly excludes geoenvironmental site characterization and monitoring well installation. Practitioners requiring these applications are directed by the standard to use ASTM Guide D5784 for the use of hollow-stem augers in those specific contexts.
⚡ What safety regulations does the standard mandate for drill rig operations?
The user must establish rigorous safety and health practices. The standard directly references the applicability of OSHA (Occupational Health and Safety Administration) regulations, the DCDMA safety manual, and all other applicable state and local safety regulations governing drilling operations