Pretend you are a teacher preparing a quiz for the text I will provide. 
            Each quiz question should follow the format below. 
            Ensure that you carefully recheck the questions and answers for accuracy. 
            The output should be a ready-to-use list of dictionaries for the Python eval function:

            [

                    "question": "WRITE THE QUESTION HERE",
                    "options": ["A) OPTION_1", "B) OPTION_2", "C) OPTION_3", "D) OPTION_4"],
                    "answer": INDEX_OF_CORRECT_ANSWER_IN_OPTIONS_LIST,
                    "explanation": "EXPLAIN WHY THE ANSWER IS CORRECT"

            ]

            Text:
            f overlapping stress zones footings or raft; depth ≈ 1.5 B [Figs. (2.11c and 
2.11b)]. 
The American Society of Civil Engineers, ASCE (1972) suggested that the minimum 
depth of boring is the smallest depth of the following (unless bedrock is encountered): 
A. The depth of B.Hs. should extend to the point where the net increase in stress due to 
the building load is less than (10 %) of the contact pressure [see Fig. (2.12)]. 
B. The depth of B.Hs. should extend to the point at which the net increase in stress due 
to the building load is less than (5 %) of the effective overburden pressure [see Fig. 
(2.12)]. 
 
Chapter Two 
 
Soil Exploration 
 
19 
 
For hospitals and office buildings, Sowers and Sowers (1970) used the following 
rules: 
A. For light steel or narrow concrete buildings; depth (m) = 3 S 0.7   
B. For heavy steel or wide concrete buildings; depth (m) = 6 S 0.7 ; where S is the 
number of stories. 
 If bedrock is countered, the minimum depth of core boring into the bedrock is about 3m. 
 Deep Foundations: If piled foundation is expected, depth of boring should satisfy the 
following: 
A. Depth of boring should extend to (3-5) times pile diameter (or width) or 3m into the 
bearing stratum. 
B. Tomlinson suggested that the boring depth should extend below the pile-point of at 
least (      
 
 ) as shown in Fig. (2.11 d). 
 
 
 
 
 
 
 
 
 
 
Fig. 2.11 Depths of boreholes for various foundation conditions 
 
 
1.5 
1.5 
1.5 B 
Chapter Two 
 
Soil Exploration 
 
20 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 2.12 Determination of the minimum depth of boring 
 
2.9 In-Situ (Field) Tests 
In-situ tests are used to identify soils at a site and to provide soil parameters for design. The 
results are available quickly, often during the tests or soon after, compared with laboratory 
tests. There are a variety of in-situ tests available. The most commonly used in-situ tests are: 
 Standard penetration test (SPT) 
 Cone penetration test (CPT) 
 Vane shear test (VST) 
 Plate load test (PLT) 
 
2.9.1 Standard Penetration Test - ASTM-D1586 
It is the most popular and economical method to obtain sub-surface information. The test 
consists of driving the standard split-barrel sampler [see Fig. (2.7a)] a distance of 460 mm 
(18) into the soil at the bottom of the boring, using a 63.5 kg (140 lb) driving mass falling free 
from a height of 760 mm (30), see Fig. (2.13). The number of blows required to drive the tube 
the last 305 mm (12) should be counted to obtain the (N) value. 
 
 
 
Chapter Two 
 
Soil Exploration 
 
21 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig. 2.13 Driving sequence in an SPT 
Advantages of SPT 
1. The test is too economical. 
2. It produces a visual profile of a great percentage of boring depth. 
3. The test results in recovery of samples. 
4. Long service life of equipment in use. 
5. The accumulation of a large SPT data-base which is continually expanding. 
 
Corrections of N-values 
Various corrections are applied to the N-values to acc

            Quiz: