Standard penetration test

As defined above, penetration is the movement of a chemical throngh holes in the material or fabricated component of PPE. Standard penetration tests exist and are described below. In general, these tests have been found either not applicable or are not practiced by the research community involved in studies pertinent to protection from pesticides. 

The usual method for obtaining samples at significant depths below the surface is to push or drive a pipe or tube into undisturbed soil at the bottom of a drill hole. Of course, this process disturbs the soil, particularly when the pipe is heavy walled. Many different kinds and sizes of samplers are used, and the most common is shown in Figure 1.1. This sampler is commonly called a split spoon. When used with the dimensions shown, and hammered into the soil by a free falling, 140 pound weight, dropping 30 inches, this is the Standard Penetration Test (see ASTM Standard D.1586,... 

In-situ density of a granular deposit at or near the ground surface is generally determined by field tests. These include sand cone, rubber balloon, and nuclear methods. These tests are described in ASTM Standards D-1556, D-2167, and D-5195. Density of deep deposits may be estimated from the results of probe tests such as the Standard Penetration Test (SPT), and the... 

The relative density of a granular formation is generally an important design factor when strength and settlement characteristics are involved. The standard penetration test gives data which when coupled with pertinent experience yield reliable estimates of relative density. Chemical grouts may also be used for this purpose. 

Shear Wave Velocity, Vs feet/second (m/s) Standard Penetration Test, Af [or NchIot cohesionless soil layers] (blows/foot) Undrained Shear Strength, s psf (kPa)... 

Methods of in situ measurement of strength. CPT, cone penetration test DMT, dilatometer test PMT, pressuremeter test SPT, standard penetration test VST, vane shear test. 

The plate load test is well known and, like the standard penetration test, has been in use for a long time period, but neither of these two tests is used very often when the water depth is greater than about 30 m. A limited niunber of plate bearing tests (plate loading test [PLT]) have been carried out at three locations in the North Sea typically, a seabed jacking system has been used to load the plates. The main limitation of the PLT is that it only tests the upper 0.5-1.0 m, luiless it is of the screw-plate type (Kummeneje, 1955 Schmertmann, 1970). 

The three important methods used for geotechnical site classifications are based on (i) Standard penetration test (SPT) (ii) Cone penetration test (iii) Average shear wave velocity in the top 30 m (V °). Of these, the oldest and the most widely used method of site classification is based on SPT values. There are many correlations available for evaluating different soil parameters based on the SPT values. The site classification schemes available based on the standard penetration test (SPT) values are given in Table 2. 

Eurocode-8(2003) has also classified the site based on F/ , standard penetration test (SPT) values and cone penetration test (CPT) values. 

The Standard Penetration Test (SPT) was conducted to a depth of about 60 to 80 m at 150 locations in the site. The water table is found to be at a depth of 30 m below the ground level. The top 2.5 to 4.0 m layer is clayey sand (SC) with... 

Standard penetration test (SPT) Sand Soft to firm clays Qualitative evaluation of compactness Qualitative comparison of subsoil stratification ASTMD 1586-67 Peck et al. (1974) Tavenas(1971) Kovacs et al. (1981) ESOPTII (1982) Schmertmann (1979) BS 5930 (1999)-Cl 25.2... 

Figure 4.7. Chart for spread footings on sand. Corrected standard penetration test results related to foundation size and loading for approximately one-inch settlement. Water table at more than depth B below footing.

The value of S can be estimated based on field tests such as the Standard Penetration Test (SPT). Figure 5.6 shows an example of a relationship between uncorrected SPT Vvalue and S for clayey sand complied by Sambhandaraksa Pitupakhorn (1985) from their work in Thailand. 

Note that in Equation 5.15, unit weight is assumed to be equal to unit weight of pile. Because Nq is dependent on 0, a sample has to be obtained and tested for 0. For sand and granular soils, it is difficult to obtain their undisturbed samples. Because of this, an in situ test is usually performed to obtain 0. Two in situ test methods normally used are the standard penetration test (SPT) and cone penetration test (CPT). Some of these correlations have been presented earlier in this chapter. Figure 5.8 shows a plot of the bearing capacity factor, Nq. 

The project was a reinforced concrete (R.C.) bridge over a river in Selangor, Malaysia. The proposed heights of the approach embankments on both sides of the abutments were about 8 m with side slope of 1F (vertical) to. 5H (horizontal). These embankments were to be constructed over a layer of very soft silty clay or clayey silt of 3 m to 9 m thick with Standard Penetration Tests values SPT) N of zero. Underlying the very soft top layer was 3.5 m to 5.5 m thick of medium dense silty sand followed by completely weathered shale with SPT W values varying between 30 to 50 blows/300mm. The liquid limit (w/) of the clay was about 78% and average moisture content was about 106%. 

Similarly for a construction site, the nature or consistencies of the sub-surface soil strata would depend on the weathering profiles. In residual soils, for example, the soil strata would generally show increasing stiffness with depth, as evidenced by increasing Standard Penetration Test values with depth. Hence the deeper the soil stratum, the higher the bearing capacity and shear strength. 

In addition to the irregular or highly pinnacled bedrock profile and solution cavities, the occurrence of very weak slumped materials immediately above the limestone bedrock is yet another geological feature of great concern to the foundation engineers. These weak slumped materials are characterised by their very low Standard Penetration Test (SPT), N values ofFigure 14.4. Their origin or formation plus additional characteristics have been discussed previously (Tan 1988,... 

If this correction was not made, Terzaghi and Peck suggested that the relative density of even moderately dense very fine or silty submerged sand might be overestimated by the results of standard penetration tests. In gravel deposits, care must be taken to determine whether a large gravel size may have influenced the results. Usually, in the case of... 

Stroud, M.A. 1988. The standard penetration test its application and interpretation. Penetration Testing in the UK., Thomas Telford, London 29-49. 

Driven sampling using Standard Penetration Test (SPT) or other size samplers is the most widely used sampling method. Although this sampling method recovers a disturbed sample, the blow count measured with this type of procedure provides a useful index of soil density or strength. 

Based on Standard Penetration Tests (SPT) Based on Cone... 

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