Dynamic Cone Penetrometer Presented By Rakib Hossain

Group Members Tania Islam-09 Shahriar Safi Hasan -08 Asif Iqbal-50 Md. Shihan Rahman-31 Rakib Hossain-113 Tanvi Jahan Chaity-136 Ruhul Amin Shipon-32 Sanjida Akter-40 Shihabuddin-90 Md. Mohiuddin Shikdar-203 Md. Sanjidur Rahman-139 Jannatul Ferdous-93 Md. Shahidul Islam-110 Mijanur Rahman-85 Estefazur Rahaman Mobin-142 Iqbal Hossain-112 Monir Hossain-147 Md. Shahidul Islam-130

Supervisor Prof. Dr. M. Shahidul Islam Co-ordinators Prof. Dr. Hafiza Khatun Chairman Pro. Borhan Uddin Supernumerary Professor Md. Faruk Hossain Assistant Professor

Contents of the Presentation Definitions of DCP Instruments of the designed DCP Methods Outcomes of the test Limitations Recommendations

What is DCP ? A typical Dynamic Cone Penetrometer (DCP) consists of two steel shafts; in operation, they are fitted together to form a single shaft. The upper shaft has a handle at the top; the hammer is fitted to this shaft, and able to slide freely on it. The lower shaft has a fixed metal cylinder, called the anvil, at the top; the shaft is marked in increments, typically 5 mm. The base of the upper shaft fits into the center of the anvil, and when the operator raises and drops the hammer, it lands on the anvil. The cone is fitted into the lower end of the lower shaft; the impact of the hammer on the anvil drives the cone into the soil.

What is DCP?   Dynamic Cone Penetration (DCP) testing is used to measure the strength of in-situ soil and the thickness and location of subsurface soil layers. The Dynamic Cone Penetration Test (DCPT) is a widely-used and very simple test for soil compactness and load-bearing capacity. 

Design and making of DCP It is a matter of joy that the DCP has been designed and made by the honorable Professor Dr. M. Shahidul Islam. His enthusiasm, interest, perseverance, hardwork has made the innovation possible. We are also excited that we have run the test for the first time but got a tremendously good findings. It has added a fantastic and positive experience to know the subsurface conditions of the earth without digging any hole or more manual support. We hope that the innovated DCP will be more helpful to get success in context of getting the conditions of the surface.

Instruments of the designed DCP Anvile This serves as the lower stopping mechanism for the hammer. It also works as a connector between the upper and lower shaft. This allows for disassembly which reduces the size of the instrument.

Hammer It is manually raised to the bottom of the handle . Then, it is dropped to transfer energy through the lower shaft. It plays the significant role for conducting the DCP operations. The whole operation depends on the shape and size of hammer.

Steel Shaft Upper shaft is a steel shaft on which the hammer moves. The length of the upper allows the hammer to drop . The lower shaft is a steel shaft increments for recording the penetration after each hammer drop.

Cone The cone is fitted into the lower end of the lower shaft; the impact of the hammer on the anvil drive the cone into the soil.

Methods of DCP Generally, the DCP will be disassembled when stored and transported, so you must assemble it before use. To do this, you will usually insert the bottom of the upper shaft into the anvil end of the lower shaft, line up the connecting-pin (or bolt) hole, and insert the pin/bolt, washer, and retaining clip. You should inspect the cone before attaching it to the lower tip of the shaft, both before and after use, to see if it is worn or damaged.

Step 1 : Preparing the test spot A DCP is designed to penetrate soil, rather than asphalt, concrete, or other hard surfacing materials. The place selection is significant in getting a good result In order to test the soil beneath such a material, a hole (typically about 2 inches in diameter) should first be cut or drilled down to the actual soil.

Step 2 : Setup To conduct the actual test, First place the DCP in a vertical position, with the tip of the cone resting on the soil. One should establish a reference level before proceeding with the test. If the measuring device is not available a built-in reference, it can be done by placing a ruler, straightedge, or other flat, rigid object on the soil close to the cone. It should remain in that position throughout the test.

Step 3 : Running the test Raise the hammer to the top of the shaft, being careful not to hit it against the handle. After each drop, record the position of the shaft in relation to the reference (usually to the nearest millimeter or 0.1 inch). Continue to do this either until the shaft reaches the required depth or until you have dropped the hammer the required number of times . After the test, remove the shaft from the ground inspect it, disassemble it, and put it back in its transport case.

Step 4 : Collection and preservation of the sample After each drilling and digging, the soil samples should either be preserved in the chambers of the instruments itself. However if there is risk of damage while carrying them in the instrument containers, then the soil samples should emptied carefully into plastic wraps and transported with care. The plastic wrap prevents the soil quality from being degraded or altered by the presence of atmospheric gases in the air.

Outcomes of the test at Teknaf Soil: We found surface soil consisting of three layers. a)Upper layer b)Middle layer c)Lower layer The soil compaction of whole Shah Porir Dwip is average. It means that the type of soil consisting the total island is everywhere nearly same. The upper layer of the soil is hard. Then the middle layer is loose soil. We could easily penetrate through the middle layer and point to point penetration difference was much higher. It was less hard than the top layer. And the hardest layer was the lower portion. When the penetration difference value came nearly zero, we stopped penetrating at that point because the dynamic cone penetrometer was at risk of damaging because of hard soil layer.

Vegetation area Settlement area The soil type was hard - less hard - vary hard condition. This means in this soil water can easily leach through upper and middle layer and can hold the water on top of lower layer which can be good for agricultural small root plants. Settlement area In this area, this soil type was not very versatile. There was little penetration difference in the settlement area. As the houses are kutcha in shah porir dip, so the area is moderately hard.

Woodland area Riverside School side The subsoil compaction is very dense in woodland area. As the tree roots are spread out at a very long distance under the surface, so we cannot penetrate the woodland area very deeply. The cone of the penetrometer gets stacked in the root of the wood trees. Riverside The soil of the riverside area is moderately loose. Water can easily leach into the lower part. School side There are huge amount of tree around the school. We penetrate both the front side of the school & the back side of the school. The soil of both locations is moderately hard.

Outcomes of the DCP test at Saint Martin We penetrated the vast area of the Saint Martin Island. Our course teacher provided us a map of the island in order to easily locate the spots. Firstly, we selected the spots & we penetrated 3 times on the spot by selecting high shore, middle shore & low shore.

High Shore Difference We penetrated 15 spots in high shore. The soil compaction of high shore is not so loose. After penetrating around a defined distance, we couldn’t penetrate. Because there were huge amount of stones (coral). The soil of the upper portion of the island is soft. Water can easily leach there. In high tide, water covers the whole area. For this reason, the soil gets wet in the high tide. In low tidal period then water don’t stay in the high shore. At that time the soil seems hard.

Saint Martin 1(a) High shore Sl no Penetration Difference 1 2.5 2 4 1.5 3 5.5 7 5 8 6 9 10 11 11.5 6.5 12 12.5 Sl no Penetration Difference 1 12 2 17 5 3 19 14 4 24 10 28 18 6 32 7 38 8 43 9 46 27 50 23 11 54 31 57 26 13 60 34 63 29 15 66 37 16 70 33 74 41 77 36 81 45 20 85 40 21 88 48 22 91

Middle Shore Difference We penetrated over a little spot of middle shore. Because there were some spots which distance (shore to settlement area) is small. That’s why we penetrated over small points of middle shore. The soil compaction of middle shore is less hard than the high shore. The upper portion of the soil is too loose that the penetration difference was higher. But after reaching a defined distance we couldn’t penetrated as there were stones under the island.

Low Shore Difference We penetrated a little location than high shore because of high tide. As time was running and in Saint Martin Island 12pm is the starting time of low tide. For this reason we could not penetrate the low shore though this time.

Limitations The instruments are not easy to carry from one place to another . Through using the DCP, it is not possible to reach to the more depth of the surface. The DCP is not capable of giving an exact scenario. The instruments are easily breakable. The innovated instruments are so weighty. It requires a time consuming and long process. It demands several persons to run a test.

Recommendations There are some recommendations which can be helpful for the development of DCP. The innovated DCP should make more apt for reaching the more depth of the surface. The instruments should be more strong and viable. The DCP should be developed in such a way when it can be used in any spot. The laboratory support can be increased for experiments. To increase some professional figures is needed who understand the whole procedures of DCP.

Working Site Photos