Soils Special Inspection Test Questions

In a special inspection daily report of soil testing, all relevant information about the tests conducted should be included. This includes the number of tests performed, the location of the tests, and the test results. However, the height of the building is not directly related to the soil testing and therefore does not need to be included in the report.

After completing an in-place density test that failed, the first person to be contacted should be the Contractor. The Contractor is responsible for the construction work and is directly involved in the execution of the project. They should be informed immediately about the failing test so that they can take appropriate actions to rectify the issue and ensure that the necessary corrective measures are implemented. The Contractor can then communicate with other parties involved, such as the Engineer of Record or Architect, if necessary, to address the problem effectively.

A nuclear gauge should be standardized once a day to ensure accurate and reliable measurements. Standardizing the gauge involves comparing its readings to a known standard to calibrate it. By standardizing daily, any potential drift or changes in the gauge's performance can be detected and corrected promptly, minimizing measurement errors. This frequency of standardization helps maintain the gauge's accuracy and ensures that it is consistently providing reliable data for nuclear density testing.

The specific gravity of a material refers to its density compared to the density of water. It is not a function of compaction effort because it is a characteristic property of the material itself, unrelated to the process of compacting the soil. Compaction effort, on the other hand, refers to the amount of force applied to the soil during the compaction process, which can affect its density and compaction characteristics. Therefore, specific gravity is not a factor that is influenced by compaction effort.

If the density and moisture readings become suspect according to ASTM 6938, performing another standardization test is recommended. This is because a standardization test helps to calibrate the testing equipment and ensure accurate and reliable readings. By performing another standardization test, any potential issues or inaccuracies in the readings can be identified and corrected, ensuring the reliability of subsequent test results.

The correct answer is 200. This means that there are 200 linear feet between Stations 0+00 and 2+00.

The peak of a proctor curve represents the maximum dry density and optimum moisture content. This point on the curve indicates the highest density that can be achieved for a given soil at its optimum moisture content. It represents the ideal conditions for compacting the soil to its highest possible density, which is important for construction and engineering purposes.

When performing Method C of ASTM D 1557, the 10 lb hammer should be used. This is because ASTM D 1557 specifies the use of a 10 lb hammer for Method C, which is a standard test method for determining the maximum dry density and optimum moisture content of soils. The use of a 10 lb hammer ensures consistency and accuracy in the test results.

Percent compaction is a measure of how much the soil has been compacted compared to its maximum dry density. It is calculated by dividing the dry density of the soil by the maximum dry density and multiplying by 100. In this case, the dry density is 115.2 and the maximum dry density is 120.4. Dividing 115.2 by 120.4 and multiplying by 100 gives a percent compaction of 95.8, which is closest to 96. Therefore, the correct answer is 96.

The survey stake reading C250 indicates that the ground level is too high by 2.5 feet.

The current elevation of the slope is 1068.2. This is determined by taking three 6-ft readings and an additional 2-ft reading with a hand level. By adding these readings to the elevation of the graded building pad (1048.2), we can determine the current elevation of the slope.

The dry density of a soil can be calculated by dividing the wet density by the sum of 1 and the moisture content, then multiplying the result by 100. In this case, the wet density is 123.2 and the moisture content is 14.2%. Therefore, the dry density can be calculated as (123.2 / (1 + 0.142)) * 100 = 107.9.

The Plasticity Index (PI) is a key measure in soil mechanics, quantifying a soil's plastic characteristics. It's calculated by subtracting the Plastic Limit (PL) from the Liquid Limit (LL). This difference reflects the range of moisture content over which soil behaves plastically, offering insights into its workability and stability, crucial for understanding and predicting soil behavior in engineering applications.

According to the International Building Code, the maximum lift thickness of backfill material is 8 inches. This means that when backfilling a trench or excavation, the material should be placed in layers no thicker than 8 inches at a time. This ensures proper compaction and stability of the backfill, reducing the risk of settlement or damage to the structure.

A cobble is a type of sedimentary particle that has a grain size between 3 inches and 12 inches. It is larger than a pebble but smaller than a boulder.

When determining the water content of soil when it just begins to crumble when rolled into a 1/8-inch thread, you are determining the Plastic Limit of ASTM D 4318. The Plastic Limit is the water content at which a soil transitions from a plastic state to a semi-solid state. It represents the minimum moisture content at which the soil can still be molded into a specific shape without crumbling.

The moisture content can be calculated by subtracting the dry density from the wet density and dividing the result by the dry density. In this case, the calculation would be (121.4 - 108.9) / 108.9 = 0.115 or 11.5%.

The required percent compaction of fill soils for the project is 95% of Standard Proctor. This means that the fill soils need to be compacted to a density that is 95% of the maximum dry density determined by the Standard Proctor compaction test. This test measures the maximum density that can be achieved for a given soil by compacting it at a specific moisture content and energy level. Achieving 95% compaction ensures that the fill soils are sufficiently dense and stable for the project.

When surface irregularities are found when using the nuclear gauge for density testing, it is appropriate to use no more than 1/8 inch of filler material. This is because using too much filler material can affect the accuracy of the density testing. By limiting the amount of filler material to 1/8 inch, the surface irregularities can be accounted for without compromising the accuracy of the test.

Vertisols are clay-rich soils with a high content of smectite, a type of expansive clay mineral. These soils undergo significant volume changes with fluctuations in moisture content, shrinking and cracking during dry periods and swelling when wet. This shrink-swell behavior can cause damage to foundations, roads, and other infrastructure, and also poses challenges for agriculture due to the formation of deep cracks and the difficulty of tillage.

The maximum rock size allowed in fill material is 3 inches.

The best compaction equipment for clayey and silty soils is a non-vibe sheep's foot. Clayey and silty soils are cohesive and have a high moisture content, which makes them prone to excessive compaction. The non-vibe sheep's foot, also known as a padfoot roller, is designed specifically for compacting cohesive soils. Its cylindrical drum is covered with "feet" or pads that penetrate the soil, creating kneading and shearing forces that help to compact the soil effectively. The non-vibe sheep's foot is preferred over other options like the vibratory sheep's foot, vibratory flat-drum roller, and tracked by dozer for these soil types because it provides better compaction results.

Nested rock should never be used when using rock fill. Nested rock refers to placing larger rocks within the gaps or spaces between smaller rocks. This practice can lead to instability and poor compaction of the rock fill, which can compromise the overall strength and stability of the structure being built. It is important to ensure proper compaction and uniformity of the rock fill to achieve the desired structural performance.

The given sentence is incorrect because the Liquid Limit (LL) is too low. A CH soil typically has a higher Liquid Limit, indicating that it has a higher plasticity and can retain more water. In this case, the LL of 35 is lower than expected for a CH soil, suggesting that the soil may not exhibit the desired plasticity and may not perform as expected in certain engineering applications.

A static sheepsfoot roller is not recommended for rock fill material because it is not effective in compacting rocks. The sheepsfoot roller is designed for cohesive soils such as SW (well-graded sand with gravel), CL (lean clay), and GAB (graded aggregate base), where the protruding feet or pads on the roller can penetrate and compact the soil. However, rocks are too hard and irregular in shape for the sheepsfoot roller to effectively compact them. Therefore, a different type of compactor or method would be more suitable for compacting rock fill material.

Stripping and grubbing verification should be performed prior to grading to ensure that all vegetation, including trees, shrubs, and roots, has been completely removed from the site. This is important because any remaining vegetation can interfere with the grading process and potentially cause issues with the stability and integrity of the construction project. By verifying that the site is clear of vegetation before grading, the construction team can proceed with confidence and minimize any potential complications that may arise from incomplete vegetation removal.

D698 Method C should be used when 30% or less of the material is retained on the 3/4 sieve. This method is specifically designed for testing the maximum dry density and optimum moisture content of soils with a maximum particle size of 3/4 inch or smaller. By using this method, engineers and construction professionals can determine the compaction characteristics of the soil and make informed decisions about its suitability for various construction projects.

According to ASTM D 75, the field sample mass that must be obtained when the maximum aggregate size is 12.5 mm is 15 kg.

When performing a standardization check on a nuclear gauge, it is recommended to perform four repetitions. This is because repeating the process multiple times helps to ensure accuracy and reliability of the measurements. By taking multiple readings, any inconsistencies or errors can be identified and corrected, leading to more precise and consistent results. Therefore, performing four repetitions is essential for obtaining reliable data from the nuclear gauge.

The percent compaction can be calculated by dividing the dry density of the sample obtained from the hole by the maximum dry density and multiplying by 100.

Dry density = (Weight of sample obtained from hole - Weight of moisture) / Volume of sample obtained from hole
Weight of moisture = Weight of sample obtained from hole - Weight of dry sample
Volume of sample obtained from hole = Weight of sample obtained from hole / Density of sand

Plugging in the given values:
Weight of moisture = 10.4 lbs - (10.4 lbs * 0.03) = 10.4 lbs - 0.312 lbs = 10.088 lbs
Volume of sample obtained from hole = 10.4 lbs / 95.3 lbs/ft3 = 0.109 ft3
Dry density = (10.4 lbs - 10.088 lbs) / 0.109 ft3 = 3.012 lbs/ft3

Percent compaction = (3.012 lbs/ft3 / 143.6 lbs/ft3) * 100 = 2.098%

Therefore, the correct answer is 91.8%.

The diameter of the pipe between Yard Inlets A4 and A5 is 24 inches.

According to the International Building Code, all of the mentioned tasks require periodic inspection except for "In the presence of more than 12 inches of fill, verify use of proper materials, densities, and lift thicknesses." This means that for any fill that is more than 12 inches, there is no need to verify the use of proper materials, densities, and lift thicknesses. However, the other tasks mentioned, such as verifying materials below footings, verifying excavations, and verifying the use of proper materials, densities, and lift thicknesses in the presence of less than 12 inches of fill, all require periodic inspection to ensure compliance with building code regulations.

The correct answer is 16 hours because the standard Proctor test requires a minimum standing time of 16 hours for the moisturized specimen. This standing time allows the soil to fully absorb the moisture and reach its maximum density before further testing or analysis is conducted.

When the operator turns on the machine and causes vibrations, additional sand enters the hole during the sand-cone density test. This means that there is more sand in the hole, which will increase the volume and decrease the dry density of the soil. Therefore, the test results will show a lower dry density.

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The Proctor test, developed by Ralph R. Proctor, is a laboratory method used to determine the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density. The test is essential in preparing for the construction of foundations, roadbeds, and other structures requiring compacted earth for stability. By establishing the optimal moisture content, the Proctor test helps ensure that soil can be compacted to meet specific engineering standards and project specifications, thereby enhancing the strength and stability of the constructed structure.

Based on the Atterberg Limit testing results, the liquid limit (LL) of the soil is 52 and the plastic limit (PL) is 18. According to the Unified Soil Classification System (USCS), a soil with a high plasticity index (PI = LL - PL) is classified as CH, which stands for clay of high plasticity. Therefore, the classification of this soil would be CH.

Using the nuclear gauge for moisture content in a 3 ft. deep trench is not acceptable. The nuclear gauge is used to measure the density and compaction of soil, not moisture content. Moisture content is typically measured using other methods such as a moisture meter or a drying oven. Therefore, using the nuclear gauge for moisture content in this context would not provide accurate results.

Based on the information provided, the approximate center of the proposed library requires 7 feet of fill. This is determined by adding the slab thickness plus stone base thickness of 1 foot.

The correct answer is 1024. This can be determined by referring to Page 1 of the plans where the elevation of the inlet structure at A10 is stated to be 1024.

The distance of the storm drain between A4 and A5 is 92 feet.

Reworking refers to the process of modifying or improving the subgrade soils by various methods such as adding or removing materials, compacting, or stabilizing. It is a common practice in construction projects to ensure the stability and strength of the foundation. Unlike outcropping, which refers to the exposure of natural rock or soil, jetting, which involves using high-pressure water to loosen and remove soil, and overexcavation, which refers to digging deeper than required, reworking specifically focuses on altering the existing subgrade soils to meet the project requirements.

Based on the information given, the correct answer is 5. This suggests that at Station 2+00, approximately 5 feet of fill will be needed to reach the desired grade.

Based on the given information, it is stated that the necessary fill above the top of the pipe at Yard Inlet A5 should be back at the existing grade. The correct answer is 4, which means that approximately 4 feet of fill is required above the top of the pipe to reach the existing grade.

Based on the information provided, if 81 linear feet of 24 inch pipe extends from inlet A3 to A4, it would place inlet A4 at station 2+31.