Downhole sampling method and device used in standard penetration test

Abstract

A sampling device has a closed housing, a split-barrel sampler, an anvil, a drop hammer and a lifting device. The split-barrel sampler is mounted in and extends out from the bottom end of the housing. The anvil is attached to the top of the split barrel sampler. The drop hammer is moveably mounted in the housing and is located above the anvil. The lifting device is mounted in the top end of the closed housing to lift the drop hammer to a specific height above the top of the anvil. With the sampling device, the impact energy generated by the hammer is directly transmitted to the sampler through the anvil. The impact energy lost is minimized, and the accuracy of the Standard Penetration Test result is improved.

Description

[0001] 1. Field of the Invention[0002] The present invention relates to an impact method and a sampling device, and more particularly to an impact method and a device used in Standard Penetration Test (SPT), which can enhance the impact energy by reducing the energy lost during testing.[0003] 2. Description of Related Art[0004] Construction engineers in the United States commonly use the Standard Penetration Test (SPT) as a routine prerequisite in subsurface investigations for foundation design. As a common practice, the foundation design is normally accomplished on the basis of the SPT results (the N-value). The American Society for Testing and Materials (ASTM) provides Standard Method (D1586-99) entitled, "Standard Test Method for Penetration Test and Split-Barrel Sampling of Soils" for performing the SPT. The ASTM Standard Method defines the SPT test for most engineering users.[0005] The Standard Penetration Test (SPT) consists of driving a split-barrel sampling "spoon" or sample...

AI Technical Summary

Problems solved by technology

This will seriously bias the engineer's judgment and lead to a faulty conclusion with regard to the subsequent design and construction.

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