1. INTRODUCTION
The Mackintosh Probe Test is a simple and economic testing method to gather preliminary data on sub surface conditions. Such data maybe adequate for the designs of foundations for lightly loaded structures as this provides a very economic method of determining the thickness of soft deposits such as peat.
2. OBJECTIVE
• • • •
Collecting a disturbed soil sample for grain-size analysis and soil classification Determine sub-surface stratigraphy and identity materials present Evaluate soil density and in-situ stress conditions Estimate geotechnical parameters
3. THEORY/BACKGROUND The main purpose of the test is to provide an indication of the relative density of granular deposit, such as sands and gravels from which it is virtually impossible to obtain undisturbed samples. The great merit of the test and the main reason for its widespread use is that it is simple and inexpensive. The soil strength parameters which can be inferred are approximate, but may give a useful guide in ground conditions where it may not be possible to obtain borehole samples of adequate quality like gravels, sands, silts, clay containing sand or gravel and weak rock. The usefulness of SPT results depends on the soil type, with fine-grained sands giving the most useful results, with coarser sands and silty sands giving reasonably useful results, and clay and gravelly soils yielding results which may be very poorly representative of the true soil conditions. This test method provides a disturbed soil sample for moisture content determination, for identification and classification purposes, and for laboratory tests appropriate for soil obtained from a sampler that will produce a large shear strain disturbance in the sample. Soil deposits contained gravels, cobbles or boulders typically result in penetration refusal and damage to equipment. This test method is used extensively in a great variety of geotechnical exploration projects. Many local correlations and widely published correlation which relate blow count, or N-value, and the engineering behavior of earthworks and foundations are available.
4. APPARATUS • • • • • • • •
Boring Rods Rod Couplings Lifting tools Penetration Cone Hammer Wrench Ruler Marking tools
5. PROCEDURE i. ii. iii. iv. v. vi. vii. viii. ix.
x.
Connect steel cone to the bottom of a steel rod and hammer set to the top. Straighten the steel rod perpendicular to the ground surface on the point to be tested. Measure every 0.3m length of the steel rod and mark it with a chalk. Lift the hammer to the maximum position and then release. Count the number of blows than causes the rod to penetrate 0.3m. Record the data for the number of blows for every 0.3m penetration into the Mackintosh Probe test form. Remove the hammer set, and connect a new steel rod on top of the original rod in the final 0.3m. Mark again the rod for every 0.3m interval. Continue with the hammer blows and repeat the same work process. The blows should be stopped when : Number of blow reach 400 times for a 0.3m penetration because the soil has high bearing capacity, or the depth of penetration reaches 15m.Detailed site investigation is required by using boring test. Clean the steel rods, steel cone and connectors after they have been used.
6. DATA
Depth
No. of blo w/0. 3m 310 169 58 24 19 29 67 82 52 82
Cumul ative numbe r of blow 310 479 537 561 580 609 676 758 810 892
7. CALCULATION i.
Plot depth versus cumulative numbers of blows
ii.
Determine bearing capacity at 1.8 meter depth
8. PRE-LAB QUESTIONS i.
What is the advantage and disadvantage of using Mackintosh Probe test.
Advantages:
The size of a small, lightweight device causing easily handled and speed work. Tests performed earlier than tests of other sites before a project underway. Information and data were obtained more quickly, easily and save time. The cost of handling, equipment and the use of relatively cheap.
Disadvantages: Use limited in terms of the impact energy is too limited Bearing capacity of soil foundation design is a development known only superficial. ii.
List the formula to define the bearing capacity when using calculation method.
1. INTRODUCTION Soil samples are often categorized as being either disturbed or undisturbed. Hand augers are commonly used for obtaining disturbed soil samples at or near the surface and for boring to depths where samples may be obtained with a soil sampler or soil core sampler. The augers are rotated into the ground until they are filled, and then lifted out of the borehole to be emptied. A different auger can be used for each formation (soil) type. The hand auger may be used till the depth of about 6 meters (or more if required)
2. OBJECTIVE
Hand auger borings often provide the simplest method of soil investigation and sampling. They may be used for any purpose where disturbed samples are to be collected, and are valuable in connection with shallow ground water level determination and indication of changes in strata, and for advancement of a hole for insertion of undisturbed sample collection devices.
3. THEORY / BACKGROUND
An important aspect of laboratory testing is the collection of specimens for soil characterization. The process of collecting disturbed and undisturbed soil specimens requires a great deal of skill and experience depending on the quality of needed specimen. Disturbed specimens are used for visual classification and formal soil classification and for the preparation of remolded soil specimens. When obtaining disturbed specimens, geotechnical engineers are concerned only with maintaining the mineralogy and grain size distribution of the soil. In general, disturbed specimens used for the identification of soils provide engineers with approximate information about the response soil under engineering forces. Undisturbed specimens are used to characterize the properties of given soil and to determine the design. When obtaining undisturbed specimens, geotechnical engineers are concerned not only with maintaining the mineralogy and grain size distribution of the soil, but also with preserving the original water content, void ratio, and soil structure.
4. APPARATUS • • • • • • •
Soil / sand auger Extension rod Wrench Steel handle Sampling tube 38mm dia. x 230mm long / 50mm dia. x 230mm long Wire saw / trimming knife Moisture content
5. PROCEDURE
a) Undisturbed Sample i. ii. iii.
iv. v. vi. vii. viii.
Attach the auger bit to a drill rod extension and attach the T-handle to the drill rod. Begin auguring. Periodically remove accumulated sediment to prevent accidentally brushing loose material into the borehole when removing the auger. After reaching the desired depth, slowly and carefully remove the auger from boring. Carefully lower the tube sampler down the borehole and gradually force it into the sediment. Care should be taken to avoid scraping the borehole sides. Also avoid hammering of the drill rods to facilitate coring, since the vibrations may cause the boring walls to collapse. Carefully retrieve the tube sampler and unscrew drill rods. Extrude the sample directly into tubes, maintaining a uniform speed. As extrusion proceeds cut away excess soil from outside the tubes. Measure the diameter and length of sample and weigh the sample to 0.01g. Obtain representative samples for moisture content determinations. Calculate the bulk density, ρb of the soil from the following equation: ρb=
m V
b) Disturbed Sample I. II. III.
Take some of the disturbed sample every desired depth. Record the color of sample. Using your hand, find the texture of soil.
IV. V.
Classify the stickiness of soil. Classify the soil using your opinion based on the physical of the soil.
6. DATA Undisturbed Soil Determine of moisture content, w Container number Mass of container (c₁) g Mass of container + wet soil (c₂)g Mass of container + dry soil (c₃) g Moisture content, w C −C 3 W= 2 ×100 C 3−C 1
Disturbed Soil Physical of soil Depth (m) Color Textur e Sticki ness Type of soil
0.2 Light red colour
Soft, watering due to heavy rain. Soft is brittle when dry with traces of sand grains From the examination the soil can be sandy clay with some organic
material at present
7. PRE – LAB QUESTIONS
Distinguish between disturbed soil and undisturbed soil sample. DISTURBED SOIL SAMPLES In Geotechnical Engineering, disturbed soil samples do not keep the in-situ properties of the soil when in the process of collection. Geotechnical engineers do not consider them to be representative of underground soils unless if they’re for tests that don’t depend on the soil structure itself. Usually, scientists test the disturbed samples of soil for texture, soil type, moisture content, as well as the nutrient and contaminant analysis. Most of the soil samples that engineers and geologists collect are disturbed samples since they’re a lot easier to collect and the precision necessary for gathering an undisturbed sample isn’t required for many soil tests. UNDISTURBED SOIL SAMPLES Undisturbed soil samples keep the structural integrity of the in-situ soil and they have a higher recovery rate in the sampler. It’s actually tough to gather a perfect undisturbed sample and the samplers may contain a small portion of undisturbed soil at the top as well as the bottom of the sample length. Undisturbed samples allow the engineer to identify the properties of strength, permeaility, compressibility, as well as the fracture patterns among others. Usually, the results of these analyses help many geotechnical engineering firms in terms of designing a new building.
8. DISCUSSION I.
Give the type of land suitable for investigation using the above method . If this method be carried out on sandy soil explain the steps to be taken.
II.
Provide appropriate limit research into soil auger. Explain why this method is not suitable for the deeper point.
III.
This method is used in the land parched, medium and wet and happy at penetrating. This tool cannot be used on sandy soil. Land of low viscosity will cause the land is not attached to the device when the pull-out.
Extension rods measuring only im long. This method is not suitable for more in point because this method uses limited manpower and the height does not exceed the human breast.
Give the type of construction sites where the level of research hand auger methods and provide an explanation.
Hand auger method suitable for the construction of low – cost housing etc. Energy to bring is small and space facilities to anyone especially low-class contractors to use and does not require high costs to get it from other equipment.
9. CONCLUSION
From the activity in this laboratory work, we have learnt and applied two methods of soil sampling known as disturbed and undisturbed. The undisturbed soil sample was obtained
using a sampling tube and has little effect on the properties of the soil. From this sample, we have determined the moisture content of soil. From visual examination, the type of soil assumed is sandy clay with some mineral content due to the sand particles present in the soil after drying. The mineral content or peat is seen in the soil represented by some black soft patches. However, visual examination is indefinite and unreliable.
10. REFERENCE
1. http://cc304.blogspot.com/2013/01/example-of-lab-report-geotechnics.html 2. http://www.academia.edu/4117852/SOIL_INVESTIGATION_HAND_AUGER_ 3. https://geotechengineeringsoftware.wordpress.com/2013/06/12/geotechnicalengineering-the-difference-of-disturbed-and-undisturbed-soil-sampling/
1. INTRODUCTION
The proctor compaction test is a laboratory method developed according to some standards to experimentally determine the optimum water (moisture) content at which a given soil type would become most dense and achieve its maximum dry density with a certain compaction effort. It has been shown that dry density of a soil for given compaction effort depends on the amount of water the soil contains during soil compaction. Therefore the relationship between the moisture content and the density of the soil is examined. Several compaction effort levels have been introduced as to match with that obtained in the field
2. OBJECTIVE
This laboratory test is performed to determine the relationship between the moisture content and the dry density of a soil for a specified compaction effort.
3. THEORY / BACKGROUND
The general meaning of the verb “compact’ is the “to press closely together”. In soil mechanics, it means to press soil particles tightly together by expelling air from void spaces between the particles. Compaction is normally done deliberately, often by heavy compaction rollers, and proceeds rapidly during construction. These three changes in soil characteristics
are beneficial for some types of earth construction, such as highways, airfields, and earth dams; as general rule, the greater the compaction, the greater the benefits will be. Compaction is actually a rather cheap and effective way to improve the properties of a soil. The amount of compaction is quantified in terms of the dry unit weight of the soil. Usually, dry soils can be compacted best (and thus a greater unit weight achieved) if for each soil, a certain amount of water is added. In effect, water acts as a lubricant, allowing soil particles to be packed together better. However, if too much water is added, a lower unit weight will result. Thus, for a given compaction effort, there is a particular moisture content at which dry weight is greater and compaction is best. This moisture content is known as the optimum moisture content, and the associated dry unit weight is called the maximum dry unit weight.
4. EQUIPMENT
Cylindrical metal mould (105mm diameter and 115.5 mm high)
Metal rammer with 50 mm diameter face, weighing 2.5kg, sliding freely in a tube which controls the height of drop to 300mm.
Measuring cylinder, 200 ml or 500ml.
BS sieve and receiver.
Large metal tray
Balance
Jacking apparatus for extracting
Small tools: palette knife, steel straight-edge, scoop.
5. PROCEDURE I.
II. III. IV. V.
VI. VII.
VIII. IX.
X.
The procedure that will be described next is applicable for soils passing the no. 5.00mm sieve. Prepare a representative batch of the soil to be tested by breaking down soil clumps into individual particles. Add water (mixing thoroughly) to the soil, until the first moisture content is attained (again, account for hygroscopic moisture as necessary). Weigh the compaction mold and base plate to 1g (0.01lb). Do not include the extension collar in this weighing. Assemble the extension collar and compaction. The soil sample will be compacted in three equal layers. Each layers is compacted with 27 uniformly distributed blows before the next layer of soil is added. Smooth the surface of the soil with light tamping and then begin compact the soil with the 2.5kg rammer. After the third layer has been compacted, remove the extension collar from the compaction mould. Using the steel straight edge, trim off the excess soil until the sample is even with the top of the mould. In the event that a small quantity of soil is lost from the compaction mould during removal of the collar or during the trimming process, fill the trimmings pressed in with moderate finger pressure. Weigh the compaction mould, base plate, and compacted soil to 1g. Extrude the sample from the mould and retain approximately 100g for a moisture-content determination. Equal portions of the sample should be obtained from each of the three layers to ensure representative water content. Break up the extruded sample by hand, and mix with excess soil from the previous compaction test. Add water, mixing thoroughly, until the water content of the soil has been raised by 2 to 3 percent.
XI. XII.
Repeat steps 4 through 10. Note the consistency of the soil and the total weight of the mould, collar, and moist soil throughout the 3 trials. Once the water content samples have been dried, determine the water content and dry unit weight of the soil in each trial.
6. DATA Volume of Mould (V) m3 =
Tria Mass of l Moist No. Specim en + Mould, Mt (kg)
Mass of Moul d, Mmd (kg)
Mass of Moist Specim en (kg)
Moisture Content Determination Can No.
Mass of Wet Soil + Can (g)
E
F
Mas s Of Dry Soil + Can (g) G
Dry Density of Compact ed Specime n, ρd
Mass of Wate r (g)
Mas s of Can (g)
Mas s of Dry Soil (g)
Moistur e Conten t (%)
H
I
J
K
L
A
B
C
D
1
5.325
3.695
1.630
91
85. 5
5.2
29. 8
56
10
156.31
2
5.413
3.695
1.718
78.8
71. 4
7.4
29. 4
42
15
151.02
3
5.418
3.695
1.723
99
84. 4
14.6
29. 6
54. 8
20
139.81
4
5.534
3.695
1.839
119. 6
96. 4
23.2
29. 6
66. 8
25
133.79
7. CALCULATIONS
Plot the moisture–density curve and find optimum moisture content, and maximum dry unit weight.
8. PRE-LAB QUESTION
State THREE (3) factor affected a process of soil compaction test
9. DISCUSSION 10. CONCLUSION 11. REFERENCE
1. INTRODUCTION
By conducting this test it is possible to determine the field density of the soil. The moisture content is likely to vary from time and hence the field density also. So it is required to report the test result in terms of dry density. The relationship that can be established between the dry densities with known moisture content is as follows:
The purpose of the test is to find the in situ density of natural or compacted soils using sand pouring cylinders.
2. EQUIPMENTS
Sand pouring cylinder
Tools for excavating holes
Cylindrical calibrating container
Metal containers
Metal tray
Digital weight scale (+/- 0.01g)
3. PROCEDURE
Calibration I. II.
III. IV. V.
VI.
VII.
VIII.
Fill the sand-pouring cylinder with sand, within about 10mm of its top. Determine the mass of the cylinder (M1) to the nearest gram. Place the sand-pouring cylinder vertically on the calibrating container. Open the shutter to allow the sand run out from the cylinder. When there is no further movement of the sand in the cylinder, close the shutter. Lift the pouring cylinder from the calibrating container and weigh it to the nearest gram (M3). Again fill the pouring cylinder with sand, within 10mm of its top. Open the shutter and allow the sand to run out of the cylinder. When the volume of the sand let out is equal to the volume of the calibrating container, close the shutter. Place the cylinder over a plane surface, such as a glass plate. Open the shutter. The sand fills the cone of the cylinder. Close the shutter when no further movement of sand takes place. Remove the cylinder. Collect the sand left on the glass plate. Determine the mass of sand (M2) that had filled the cone by weighing the collected sand. Determine the dry density of sand, as shown in the data sheet, part-I.
Determination of bulk density of soil I. Place the sand pouring cylinder concentrically on the top of the calibrating container with the shutter closed making sure that constant mass (M0) is maintained.
II.
Open the shutter of cylinder and allow the sand to move into the container. When no further movement is seen, close the shutter and find
the mass of sand left in the cylinder (M2). iii) Repeat step 2-3 at least thrice and find the mean mass (M2).
Determination of field density of soil 1. Level surface of the soil in the open field. 2. Place metal tray on the surface haring a circular hole of 10cm diameter at the center. Dig a hole of this diameter up to about 15 cm dept. Collect all the excavation soil in a tray and find the mass of excavation soil (M). 3. Remove the tray and place the sand-pouring cylinder concentrically on the hole. Open the shutter and allow the sand to run into the hole till no further movement of sand is noticed. Close the shutter and determine mass of sand which is left in the cylinder, (M 3) 4. The representative sample is taken from the excavated soil for determination of water content.
4. DATA
Determination of mass of and in the cone No Test Volume of calibrating container (m3), Vc Mass of sand in cylinder before pouring (M 0) (kg) Mean mass of sand in cone, (M1) (kg)
1 1.20 × 10
-3
9.28 0.49
Determination of bulk density of sand No Test Mean mass of sand leave in cylinder after pouring (M 2) (kg) Mass of sand filling calibrating container (Mc = M 0 – M1 – M2) Bulk density of sand (ρs = Mc / Vc ) (kg/m3)
1 7.11 1.68 1.40 × 10
-3
Determination bulk density and unit weight of soil Mass of wet soil from the hole (M) (kg)
1.73
Mass of sand in cylinder after pouring in the hole (M 2) (kg) Mass of sand in the hole, (Ms = M0 – M1 – M3 ) (kg)
2.45 6.34
Bulk density of soil , ρ = M / Ms x ρs (kg/m3)
5.13 × 10
-3
Dry density of sand ρd = ρ / ( 1 + w )
6.02 × 10
-4
No of cone Wet soil
1.73
Dry Soil
1.61
Cone Weight
0.015
Water Content %
*Formula; Vc
1
= πr2h
Mc
= M0 – M1 – M2
ρs
= Mc / V c
Ms
= M 0 – M1 – M3
ρ
= M / M s x ρs
ρd
= ρ/(1+ w)
7.52
5. PRE-LAB QUESTION
I. II.
What is the objective of sand replacement test? What is the relationship that can be established between the dry density with known moisture content?
III.
What are the apparatus that need in this test?
6. DISCUSSION 7. CONCLUSION 8. REFERENCE
