Subsoil Exploration

A soil exploration program for a given structure can be divided broadly into four phases. Which of the following correctly lists these four phases?

According to the guidelines in Table 18.1, what is the recommended borehole spacing in meters for multistory buildings?

What is a distinct advantage of using hollow-stem augers compared to solid-stem augers during subsoil exploration?

What are the respective inside and outside diameters of the steel tube used in a standard split-spoon sampler?

Using the formula from Section 18.4, calculate the area ratio (Ar) for a standard split-spoon sampler with an outside diameter (Do) of 2 inches and an inside diameter (Di) of 1.38 inches.

According to Table 18.4, what range of unconfined compression strength (qu) in kN/m^2 corresponds to a clay with a 'Stiff' consistency and a standard penetration number (N60) between 8 and 15?

During a field exploration program, rock was cored for a length of 4 ft, and the length of the rock core recovered was 3 ft. What is the recovery ratio?

What is the correct definition of the Rock Quality Designation (RQD)?

Using the qualitative description of rocks based on RQD in Table 18.7, what is the rock quality for a calculated RQD value of 0.60?

In the equation for the corrected standard penetration number, N60 = (N * ηH * ηB * ηS * ηR) / 60, what does the factor ηS represent?

What are the standard weight of the hammer and height of the drop used in the Standard Penetration Test (SPT)?

Which of the following is NOT listed as a primary purpose of subsoil exploration in Section 18.1?

Which boring method is described as using a slurry of bentonite and water (drilling mud) that is forced down rapidly rotating drilling rods to cut the soil and bring the cuttings to the surface?

A soil sample can generally be considered 'undisturbed' if its area ratio (Ar) is less than or equal to what percentage?

In the correlation for granular soil by Liao and Whitman (1986), the correction factor CN is used to convert the field N60 to (N1)60. In SI units, how is CN calculated, where σ'o is the effective overburden pressure in kN/m^2?

The Cone Penetration Test (CPT) with a friction sleeve allows for the independent determination of which two soil resistance parameters?

What is the primary reason stated in the text for using double-tube core barrels instead of single-tube core barrels when coring rock?

Which of the following graphic presentations is NOT listed in Section 18.8 as a required attachment to a soil exploration report?

The Standard Penetration Number (N), or blow count, is defined as the sum of the number of hammer blows required to drive the sampler through which specific intervals?

The correlation proposed by Wolff (1989) approximates the drained angle of friction, φ', in degrees as: φ' = 27.1 + 0.3(N1)60 − 0.00054(X). What is the term X in this equation?

What type of soil samples are obtained using a thin-wall tube sampler, also known as a Shelby tube?

Which sampling method is described as being particularly useful when 'highly undisturbed' samples are required and uses a piston to prevent sample distortion during collection?

In the context of the borehole pressuremeter test, what does the parameter Ko, calculated as the ratio of po to σ'o, represent?

What is the typical outside diameter of the most commonly used thin-wall tube samplers?

In a Cone Penetration Test, what does the friction ratio (Rf) represent?

Based on the correlation by Anagnostopoulos, et al. (2003) for the average of all cone types, the sleeve-frictional resistance (fc) can be estimated from the undrained shear strength (cu) using the equation fc = X * cu. What is the value of the coefficient X?

According to Table 18.3, what is the hammer efficiency (ηH) for a safety hammer released with a rope and pulley in the United States?

For a standard sampler with a liner used in loose sand, what is the recommended sampler correction factor (ηS) from Table 18.3?

An SPT is performed using a rod length of 5 meters. According to Table 18.3, what is the appropriate correction factor for rod length (ηR)?

What is the primary information obtained by noting the soil that holds to a hand auger during boring?

What is a major advantage of the Cone Penetration Test (CPT) over the Standard Penetration Test (SPT)?

For a standard penetration test in sand, you are given a field N60 value of 12 at a depth where the effective overburden pressure (σ'o) is 0.825 ton/ft^2. Using Skempton's correlation (Eq. 18.13), what is the corrected standard penetration number, (N1)60?

In a layer of saturated clay, a cone penetration test was conducted. At a depth of 10 m, the cone resistance (qc) was 1400 kN/m^2, and the unit weight of the saturated clay is 18 kN/m^3. Using the correlation from Case 1 in Section 18.6 with a bearing capacity factor (NK) of 18.3, what is the estimated undrained shear strength (cu) of the clay?

Determine the area ratio of a Shelby tube sampler that has an outside diameter of 114 mm and an inside diameter of 111 mm.

When is percussion drilling described as a particularly suitable method for advancing a borehole?

According to the American Society of Civil Engineers (1972) recommendation for estimating boring depths, the approximate minimum depth of boring is the smaller of two depths, D1 and D2. How is depth D2 determined?

For which type of laboratory tests are undisturbed soil samples considered necessary?

What is the typical range for the relative density (Dr) of sand that corresponds to a corrected standard penetration number, (N1)60, of 10-30, according to Table 18.5?

According to the correlation by Schmertmann (1975) as approximated by Kulhawy and Mayne (1990), the soil friction angle (φ') can be estimated from the N60 value and the effective stress (σ'o). The equation involves tan⁻¹ of a fraction. What is the expression in the denominator of that fraction?

What type of in-situ test, originally developed by Menard in 1965, involves expanding a pressure cell and two guard cells inside a borehole to measure the stress-strain modulus of the soil?

In the analysis of a borehole pressuremeter test, Zone II of the pressure-volume curve represents which type of behavior?

What is the standard base area of the 60 degree cone used in a Dutch cone penetrometer?

For a boring log, what does the abbreviation 'SS' typically represent?

Based on the correlation by Robertson and Campanella (1983) for sand, the drained soil friction angle (φ') can be approximated by the equation: φ' = tan⁻¹ [0.1 + 0.38 * log(X)]. What does the term X represent?

For a rock core sample designated 'BX', what is the diameter of the core sample obtained, according to Table 18.6?

In a sand deposit with a mean grain size (D50) of 0.26 mm and an average unit weight of 15.5 kN/m^3, a standard penetration test at a depth of 1.5 m yields an N60 of 6. Using Cubrinovski and Ishihara's correlation (Eq. 18.14), what is the estimated relative density (Dr)?

What is the key difference between the information required for the 'Compilation of existing information regarding the structure' phase and the 'Collection of existing information for the subsoil condition' phase of a soil exploration program?

For a borehole pressuremeter test, what specific value for Poisson's ratio (μs) was recommended by Menard, which simplifies the equation for the modulus of elasticity (Es) to Es = 2.66 * Vo * (Δp/ΔV)?

Trofimenkov (1974) provided correlations for the modulus of elasticity (Es) from cone penetration resistance (qc). What is the correlation given for clays?

According to Table 18.2, what is the outside diameter in millimeters of a hollow-stem auger that has an inside diameter of 101.6 mm?