Dry Density of Soil by Core Cutter Method
Cylindrical core cutters with dimensions of 130mm in length and 100mm in diameter are commonly used in testing the in-situ compaction of cohesive and clay soils when used as fill material. These core cutters are seamless steel tubes and are utilized to quickly calculate the bulk density of the soil. By determining the moisture content of the soil, the dry density of the fill can be calculated, as well as the percentage of voids present. A higher percentage of voids indicates poor compaction of the soil.
The method of using a core cutter involves pressing the cylindrical tube into the soil mass in a way that fills it with the soil without disturbing the core contents. Once the core cutter is filled with soil, it is lifted up and the mass of the soil within the cutter is determined. This mass measurement is then used to obtain the dry density of the soil, which provides important information about the compaction characteristics of the soil being tested.
The given context is related to a formula involving variables M, V, and w, which represent mass of the wet soil in the cutter, internal volume of the cutter, and water content, respectively. In this formula, M represents the mass of the wet soil in the cutter, V represents the internal volume of the cutter, and w represents the water content.
Equipment for Core Cutter Method
A cylindrical core cutter with an internal diameter of 100mm and a length of 130mm is used for cutting cylindrical samples from materials. It is typically used in construction and civil engineering applications.
The core cutter is operated using a steel rammer, which has a mass of 9 kg and an overall length of approximately 900mm, including the foot and staff. The steel dolley, which is 25mm high and has an internal diameter of 100mm, is used in conjunction with the core cutter to extract the cut samples.
Accurate measurement of the samples is done using a weighing balance with an accuracy of 1g. The palette knife and straight edge, which are usually made of steel, are used for trimming and preparing the cut samples for further testing or analysis in the laboratory. These tools are commonly used in materials testing, research, and quality control processes in various industries.
Procedure of Core Cutter Method
To determine the internal diameter and height of the core cutter to the nearest 0.25mm, carefully measure the dimensions using appropriate tools such as a Vernier caliper or a micrometer. Record the measurements for both the internal diameter and height to the nearest 0.25mm.
Next, determine the mass (M1) of the core cutter to the nearest gram by weighing it on a calibrated scale. Record the mass of the core cutter accurately to the nearest gram.
Prepare the soil sample by exposing a small area of the soil to be tested and leveling the surface to about 300mm square in area. Place the dolley over the top of the core cutter and press the core cutter into the soil mass using the rammer. Stop the pressing when about 15mm of the dolley protrudes above the soil surface.
Carefully remove the soil surrounding the core cutter, and then take out the core cutter from the soil, noting any soil that may project from the lower end of the cutter. Remove the dolley and trim the tip and bottom surface of the core cutter carefully using a straight edge.
Weigh the core cutter filled with the soil to the nearest gram (M2) on a calibrated scale. Record the mass of the core cutter and soil accurately to the nearest gram.
Finally, remove the core of the soil from the cutter and take a representative sample for water content determination. Use appropriate methods to determine the water content of the soil sample according to standard procedures. Record the water content accurately.
Observation and calculations
| Sl. No. | Observations and Calculations | Determination No. | ||
| 1 | 2 | 3 | ||
| Observations | ||||
| 1 | Core cutter No. | |||
| 2 | Internal diameter | |||
| 3 | Internal height | |||
| 4 | Mass of empty core cutter (M1) | |||
| 5 | Mass of core cutter with soils (M2) | |||
| Calculations | ||||
| 6 | M=M2 – M1 | |||
| 7 | Volume of cutter V | |||
| 8 | Water content | |||
| 9 | Dry density using formula | |||
Results of Core Cutter Method
The given context mentions the dry density of soil, which is expressed in grams per milliliter (g/ml).