Soil permeability refers to a soil's ability to transmit water and air, which is important for fish culture. A pond built in impermeable soil will lose little water through seepage. Permeability is determined by the voids between soil particles and their interconnection, which provides a path for water flow. Laboratory tests measure permeability by timing water flow through a soil sample under constant or falling head. The coefficient of permeability is calculated using measurements of flow rate, head difference, sample length and area.
1. The document describes a procedure for determining the coefficient of permeability of soil using a constant head permeameter.
2. The coefficient of permeability is a measure of how quickly water can flow through the soil and is affected by properties like particle size, void ratio, and degree of saturation.
3. The experiment involves compacting a soil sample, saturating it, then measuring the discharge of water flowing through the sample under a constant head over different time intervals to calculate the coefficient of permeability.
The document describes a laboratory experiment to determine the permeability of a soil sample using the constant head permeability test method. Three trials were conducted on the sample, which had an average dry unit weight of 1.58 g/cm3 and void ratio of 0.646. The average coefficient of permeability from the trials was determined to be 0.050733 cm/sec, classifying the sample as coarse sand according to ASTM standards. Factors that influence permeability and potential sources of error in the experiment are also discussed.
Soil water exists in three forms: free water, gravitational water, and held water. Held water includes adsorbed water forming thin films around soil grains and structural water chemically bonded to minerals. Capillary water is held tightly in small pores by hydrogen bonding, with height of rise inversely related to pore radius. Permeability is a soil property allowing water flow through interconnected voids and is important for engineering problems like seepage and drainage. Darcy's law states discharge is proportional to hydraulic gradient. Permeability is determined through constant head and falling head laboratory tests, with constant head used for permeable soils and falling head for less permeable soils.
This document outlines the procedures for determining the coefficient of permeability of soils using constant head and falling head methods. It describes the objective of the test as determining this coefficient. It then discusses Darcy's law of laminar flow that the test is based on and defines permeability. The equipment needed is listed, followed by preparation of soil specimens and testing procedures. The coefficient is reported with other soil properties. Its importance is in solving problems involving water flow through soils.
The document describes the standard Proctor compaction test procedure. The test is used to determine the maximum dry density and optimum moisture content of soils. It involves compacting soil samples at incrementally increased moisture contents using a specified compaction method. A compaction curve is plotted showing the relationship between dry density and moisture content. The peak of the curve indicates the optimum moisture content and maximum dry density achieved for that soil. The test uses a cylindrical metal mold, rammer, balance, oven and other equipment to compact and analyze the soil samples according to steps that sieve, mix, compact and weigh the soil at different moistures.
This document describes procedures to determine consistency limits of soils, including liquid limit, plastic limit, and shrinkage limit, according to IS codes. Key points:
1) The liquid limit is the water content at which a soil transitions from liquid to plastic state, defined as the water content required for a soil sample to flow together over 13mm after 25 blows.
2) The plastic limit is the water content at which a soil transitions from plastic to semi-solid state, defined as the minimum water content needed for a soil to be rolled into 3mm threads.
3) The shrinkage limit is the lowest water content at which a soil is fully saturated without changing volume during drying. Consistency limits are used
The document discusses permeability, which is the property of soil that allows water to flow through it. Permeability depends on factors like particle size, void ratio, and degree of saturation. Methods to determine the coefficient of permeability include constant head tests, falling head tests, and pumping tests. Darcy's law states that the rate of water flow through soil is proportional to the hydraulic gradient, where the coefficient of proportionality is the permeability. The law was established by Henry Darcy based on experiments in 1856 and is valid for laminar flow through saturated soils.
Consistency limits and its determinationParth Joshi
The document discusses soil consistency and Atterberg limits. It defines consistency as the strength with which soil particles bond together and resist deformation. Soil can exist in liquid, plastic, semi-solid, and solid states depending on its water content, as defined by Swedish engineer Atterberg. The liquid limit test determines the water content at which a soil transitions from plastic to liquid state and involves measuring the number of blows required to close a groove in a soil sample at different moisture contents. The plastic limit and shrinkage limit tests also evaluate consistency by measuring changes in a soil's state with varying water content.
1. The document describes a procedure for determining the coefficient of permeability of soil using a constant head permeameter.
2. The coefficient of permeability is a measure of how quickly water can flow through the soil and is affected by properties like particle size, void ratio, and degree of saturation.
3. The experiment involves compacting a soil sample, saturating it, then measuring the discharge of water flowing through the sample under a constant head over different time intervals to calculate the coefficient of permeability.
The document describes a laboratory experiment to determine the permeability of a soil sample using the constant head permeability test method. Three trials were conducted on the sample, which had an average dry unit weight of 1.58 g/cm3 and void ratio of 0.646. The average coefficient of permeability from the trials was determined to be 0.050733 cm/sec, classifying the sample as coarse sand according to ASTM standards. Factors that influence permeability and potential sources of error in the experiment are also discussed.
Soil water exists in three forms: free water, gravitational water, and held water. Held water includes adsorbed water forming thin films around soil grains and structural water chemically bonded to minerals. Capillary water is held tightly in small pores by hydrogen bonding, with height of rise inversely related to pore radius. Permeability is a soil property allowing water flow through interconnected voids and is important for engineering problems like seepage and drainage. Darcy's law states discharge is proportional to hydraulic gradient. Permeability is determined through constant head and falling head laboratory tests, with constant head used for permeable soils and falling head for less permeable soils.
This document outlines the procedures for determining the coefficient of permeability of soils using constant head and falling head methods. It describes the objective of the test as determining this coefficient. It then discusses Darcy's law of laminar flow that the test is based on and defines permeability. The equipment needed is listed, followed by preparation of soil specimens and testing procedures. The coefficient is reported with other soil properties. Its importance is in solving problems involving water flow through soils.
The document describes the standard Proctor compaction test procedure. The test is used to determine the maximum dry density and optimum moisture content of soils. It involves compacting soil samples at incrementally increased moisture contents using a specified compaction method. A compaction curve is plotted showing the relationship between dry density and moisture content. The peak of the curve indicates the optimum moisture content and maximum dry density achieved for that soil. The test uses a cylindrical metal mold, rammer, balance, oven and other equipment to compact and analyze the soil samples according to steps that sieve, mix, compact and weigh the soil at different moistures.
This document describes procedures to determine consistency limits of soils, including liquid limit, plastic limit, and shrinkage limit, according to IS codes. Key points:
1) The liquid limit is the water content at which a soil transitions from liquid to plastic state, defined as the water content required for a soil sample to flow together over 13mm after 25 blows.
2) The plastic limit is the water content at which a soil transitions from plastic to semi-solid state, defined as the minimum water content needed for a soil to be rolled into 3mm threads.
3) The shrinkage limit is the lowest water content at which a soil is fully saturated without changing volume during drying. Consistency limits are used
The document discusses permeability, which is the property of soil that allows water to flow through it. Permeability depends on factors like particle size, void ratio, and degree of saturation. Methods to determine the coefficient of permeability include constant head tests, falling head tests, and pumping tests. Darcy's law states that the rate of water flow through soil is proportional to the hydraulic gradient, where the coefficient of proportionality is the permeability. The law was established by Henry Darcy based on experiments in 1856 and is valid for laminar flow through saturated soils.
Consistency limits and its determinationParth Joshi
The document discusses soil consistency and Atterberg limits. It defines consistency as the strength with which soil particles bond together and resist deformation. Soil can exist in liquid, plastic, semi-solid, and solid states depending on its water content, as defined by Swedish engineer Atterberg. The liquid limit test determines the water content at which a soil transitions from plastic to liquid state and involves measuring the number of blows required to close a groove in a soil sample at different moisture contents. The plastic limit and shrinkage limit tests also evaluate consistency by measuring changes in a soil's state with varying water content.
Forestland soil was the most permeable to water, allowing water to pass through in just a few minutes with 0% porosity. Clay soil was the least permeable, not allowing any water to pass through and having 100% porosity. Riverbank soil and beach soil had intermediate permeability, with riverbank soil having lower permeability than beach soil as indicated by the longer time for water to pass through. Porosity and permeability were found to be related, with soils having more pore space (higher porosity) exhibiting lower permeability.
The document discusses the constant head permeability test method for determining the permeability (hydraulic conductivity) of soils in the laboratory. It defines permeability and the factors that influence it. It describes Darcy's Law and the equation used to calculate permeability from measured values. The purpose and significance of measuring permeability is explained. The test method, apparatus, procedure, calculations, analysis and results are outlined.
The document discusses various methods for measuring soil permeability in the field, including pumping tests, percolation tests, slug tests, and infiltrometer tests using single or double rings. Pumping tests involve pumping water from a well and measuring drawdown over time to calculate permeability. Percolation tests passively measure the rate of water infiltration into soil over several hours. Slug tests quickly raise and lower the water level in a well to determine how quickly the water level returns to equilibrium. Single and double ring infiltrometers measure infiltration rates using rings inserted into the soil surface.
This document defines permeability as the property of soil that allows water to flow through due to interconnected voids. It describes two laboratory methods to measure permeability - constant head and falling head tests. Darcy's law is explained, relating flow rate to permeability and hydraulic gradient. Typical permeability values are given for different soil types from gravel to clay. The constant head test procedure and calculations are outlined, along with data sheets to record measurements.
Permeability Test of soil Using Constant and Falling Head MethodJameel Academy
1) The document describes laboratory tests to determine the coefficient of permeability of soil samples using the constant head and falling head methods.
2) For the falling head test on a sandy soil sample, the average permeability was found to be 0.00322 cm/sec.
3) For the constant head test on a second sample, the average permeability was determined to be 0.02069 cm/min.
Geo technical properties of soil by sajid hussainsajid hussain
This document provides an overview of foundational principles of soil mechanics. It discusses key topics including grain size distribution, plasticity, soil classification, effective stress, consolidation, and shear strength. Sieve analysis and hydrometer testing are described for determining grain size distribution of coarse-grained and fine-grained soils. Index properties like liquid limit, plastic limit, and plasticity index are also summarized. The concepts of total stress, pore water pressure, and effective stress are introduced. Finally, the process of consolidation, whereby excess pore pressures dissipate over time under increased loading, is explained.
The document describes various methods for measuring soil permeability in the field, including pumping tests, percolation tests, single ring falling head infiltrometer tests, double ring infiltrometer tests, slug tests, and estimated methods based on grain size like the Hazen and Guelph permeameter methods. It provides details on the principles, procedures, analysis, and limitations of each method. Pumping tests and percolation tests are described as active and passive ways respectively to determine the permeability coefficient. Equations for analyzing slug test data and determining permeability from infiltrometer tests are also presented.
Determination of Liquid Limit of Soil : Civil EngineeringAbdullah Hayat Khan
This document describes the procedure to determine the liquid limit of soils according to the Casagrande cup method. It provides background on the concept of the Atterberg limits and defines the liquid limit. The objective is to establish the relationship between moisture content and blows to determine the liquid limit value. The apparatus and step-by-step procedure are outlined. An example calculation is shown. References for additional information are also provided.
This document discusses various index properties of soil and methods for determining them. It describes determining the specific gravity of soil through different methods like the pycnometer bottle method. It also discusses determining the in-situ dry density of soil using a core cutter and discusses particle size analysis through sieve analysis and sedimentation analysis. The document also describes determining the consistency limits of fine-grained soils, including the liquid limit and plastic limit tests. It defines the relative density of soils and provides categories of soil denseness based on relative density percentages.
This document discusses permeability in soil, which is the property that allows water to flow through soil. It defines permeability and explains its importance in engineering applications like earth dams and slope stability. Darcy's law states that flow through saturated soil is directly proportional to the hydraulic gradient. The coefficient of permeability depends on factors like particle size, pore water properties, degree of saturation, and soil structure. Laboratory tests like constant head and falling head tests are used to measure the coefficient of permeability.
This document discusses designing a constant head permeameter to determine the permeability of granular soils according to ASTM standards. It provides background on permeability, describes how constant head and falling head tests work, and explains the theory, basis, and general procedure of the constant head test method. Permeability is measured by monitoring the flow of water through a soil sample under a constant head, then using Darcy's equation to calculate the permeability coefficient.
This presentation includes Definition of Permeability, measurement of Permeability, Validity of Darcy's law, Darcy's Law, Methods of Finding Permeability, factors affecting permeability, Permeability of Stratified Soil
This document describes various laboratory methods for determining soil properties, including liquid limit, plastic limit, and field density. The liquid limit can be found using a Casagrande apparatus or cone penetrometer, which measure the number of blows or penetration depth required for a soil sample to close a groove at different water contents. The plastic limit is the water content at which a soil thread crumbles. Field density is measured using a core cutter method or sand replacement method.
Soil Water measurement and measurement of waterJalPanchal2
The document provides information on different methods for measuring soil water content. It discusses 12 methods including feel/appearance, gravimetric, tensiometric, electrical resistance, and neutron scattering. The gravimetric method involves taking a soil sample, weighing it, drying it in an oven, and reweighing to determine water loss. The tensiometric method uses instruments that measure soil water tension expressed in bars or centibars. Electrical resistance blocks measure soil water content indirectly through changes in electrical conductivity as water content varies.
Standard Penetration Test & Liquid Limit,Plasticity Limitgurjapsinghsomal
This document describes the procedure for conducting a standard penetration test (SPT). The SPT is commonly used to determine the properties of cohesionless soils that cannot be easily sampled. It involves driving a split spoon sampler into the ground using a 63.5 kg hammer dropped from a height of 0.75 m. The number of blows required to drive the sampler each 150 mm provides the standard penetration resistance value (N), which can indicate the relative density, shear strength, and compressibility of the soil. Corrections may be applied to N for certain soil types.
This document describes the constant head method for determining the saturated hydraulic conductivity of soil in a laboratory. It involves taking an undisturbed soil core sample and saturating it overnight. The sample is then placed on a stand with a constant head of water maintained above it. The rate of water flow through the sample is measured at intervals over 2-4 hours. Darcy's law is used to calculate the saturated hydraulic conductivity based on the water flow rate, cross-sectional area of the sample, length of the sample, and head of water. Hydraulic conductivity values are classified from very slow to very rapid.
The standard Proctor test is conducted to determine the optimum water content and maximum dry density of soil for compaction. Soil samples are compacted in layers in a standardized metal mold at different water contents using a rammer. The bulk density of each compacted sample is calculated and a curve is plotted of dry density versus water content. The water content corresponding to the highest dry density is the optimum water content. A penetration resistance test is also conducted using a Proctor needle to obtain the relationship between penetration resistance and water content.
The document provides instructions for conducting 12 geotechnical engineering experiments in the geotechnical engineering lab at B.V. Raju Institute of Technology. The experiments include determining Atterberg limits, field density via core cutter and sand replacement methods, grain size analysis, constant and variable head permeability tests, unconfined compression test, direct shear test, compaction tests, and CBR testing. Students must complete 8 of the 12 experiments listed. Instructions are provided for each experiment, including the aim, theory, apparatus required, and procedures to follow.
Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
connections. Data is transferred in the form of packets. The connections between nodes are
established using either cable media or wireless media.
Forestland soil was the most permeable to water, allowing water to pass through in just a few minutes with 0% porosity. Clay soil was the least permeable, not allowing any water to pass through and having 100% porosity. Riverbank soil and beach soil had intermediate permeability, with riverbank soil having lower permeability than beach soil as indicated by the longer time for water to pass through. Porosity and permeability were found to be related, with soils having more pore space (higher porosity) exhibiting lower permeability.
The document discusses the constant head permeability test method for determining the permeability (hydraulic conductivity) of soils in the laboratory. It defines permeability and the factors that influence it. It describes Darcy's Law and the equation used to calculate permeability from measured values. The purpose and significance of measuring permeability is explained. The test method, apparatus, procedure, calculations, analysis and results are outlined.
The document discusses various methods for measuring soil permeability in the field, including pumping tests, percolation tests, slug tests, and infiltrometer tests using single or double rings. Pumping tests involve pumping water from a well and measuring drawdown over time to calculate permeability. Percolation tests passively measure the rate of water infiltration into soil over several hours. Slug tests quickly raise and lower the water level in a well to determine how quickly the water level returns to equilibrium. Single and double ring infiltrometers measure infiltration rates using rings inserted into the soil surface.
This document defines permeability as the property of soil that allows water to flow through due to interconnected voids. It describes two laboratory methods to measure permeability - constant head and falling head tests. Darcy's law is explained, relating flow rate to permeability and hydraulic gradient. Typical permeability values are given for different soil types from gravel to clay. The constant head test procedure and calculations are outlined, along with data sheets to record measurements.
Permeability Test of soil Using Constant and Falling Head MethodJameel Academy
1) The document describes laboratory tests to determine the coefficient of permeability of soil samples using the constant head and falling head methods.
2) For the falling head test on a sandy soil sample, the average permeability was found to be 0.00322 cm/sec.
3) For the constant head test on a second sample, the average permeability was determined to be 0.02069 cm/min.
Geo technical properties of soil by sajid hussainsajid hussain
This document provides an overview of foundational principles of soil mechanics. It discusses key topics including grain size distribution, plasticity, soil classification, effective stress, consolidation, and shear strength. Sieve analysis and hydrometer testing are described for determining grain size distribution of coarse-grained and fine-grained soils. Index properties like liquid limit, plastic limit, and plasticity index are also summarized. The concepts of total stress, pore water pressure, and effective stress are introduced. Finally, the process of consolidation, whereby excess pore pressures dissipate over time under increased loading, is explained.
The document describes various methods for measuring soil permeability in the field, including pumping tests, percolation tests, single ring falling head infiltrometer tests, double ring infiltrometer tests, slug tests, and estimated methods based on grain size like the Hazen and Guelph permeameter methods. It provides details on the principles, procedures, analysis, and limitations of each method. Pumping tests and percolation tests are described as active and passive ways respectively to determine the permeability coefficient. Equations for analyzing slug test data and determining permeability from infiltrometer tests are also presented.
Determination of Liquid Limit of Soil : Civil EngineeringAbdullah Hayat Khan
This document describes the procedure to determine the liquid limit of soils according to the Casagrande cup method. It provides background on the concept of the Atterberg limits and defines the liquid limit. The objective is to establish the relationship between moisture content and blows to determine the liquid limit value. The apparatus and step-by-step procedure are outlined. An example calculation is shown. References for additional information are also provided.
This document discusses various index properties of soil and methods for determining them. It describes determining the specific gravity of soil through different methods like the pycnometer bottle method. It also discusses determining the in-situ dry density of soil using a core cutter and discusses particle size analysis through sieve analysis and sedimentation analysis. The document also describes determining the consistency limits of fine-grained soils, including the liquid limit and plastic limit tests. It defines the relative density of soils and provides categories of soil denseness based on relative density percentages.
This document discusses permeability in soil, which is the property that allows water to flow through soil. It defines permeability and explains its importance in engineering applications like earth dams and slope stability. Darcy's law states that flow through saturated soil is directly proportional to the hydraulic gradient. The coefficient of permeability depends on factors like particle size, pore water properties, degree of saturation, and soil structure. Laboratory tests like constant head and falling head tests are used to measure the coefficient of permeability.
This document discusses designing a constant head permeameter to determine the permeability of granular soils according to ASTM standards. It provides background on permeability, describes how constant head and falling head tests work, and explains the theory, basis, and general procedure of the constant head test method. Permeability is measured by monitoring the flow of water through a soil sample under a constant head, then using Darcy's equation to calculate the permeability coefficient.
This presentation includes Definition of Permeability, measurement of Permeability, Validity of Darcy's law, Darcy's Law, Methods of Finding Permeability, factors affecting permeability, Permeability of Stratified Soil
This document describes various laboratory methods for determining soil properties, including liquid limit, plastic limit, and field density. The liquid limit can be found using a Casagrande apparatus or cone penetrometer, which measure the number of blows or penetration depth required for a soil sample to close a groove at different water contents. The plastic limit is the water content at which a soil thread crumbles. Field density is measured using a core cutter method or sand replacement method.
Soil Water measurement and measurement of waterJalPanchal2
The document provides information on different methods for measuring soil water content. It discusses 12 methods including feel/appearance, gravimetric, tensiometric, electrical resistance, and neutron scattering. The gravimetric method involves taking a soil sample, weighing it, drying it in an oven, and reweighing to determine water loss. The tensiometric method uses instruments that measure soil water tension expressed in bars or centibars. Electrical resistance blocks measure soil water content indirectly through changes in electrical conductivity as water content varies.
Standard Penetration Test & Liquid Limit,Plasticity Limitgurjapsinghsomal
This document describes the procedure for conducting a standard penetration test (SPT). The SPT is commonly used to determine the properties of cohesionless soils that cannot be easily sampled. It involves driving a split spoon sampler into the ground using a 63.5 kg hammer dropped from a height of 0.75 m. The number of blows required to drive the sampler each 150 mm provides the standard penetration resistance value (N), which can indicate the relative density, shear strength, and compressibility of the soil. Corrections may be applied to N for certain soil types.
This document describes the constant head method for determining the saturated hydraulic conductivity of soil in a laboratory. It involves taking an undisturbed soil core sample and saturating it overnight. The sample is then placed on a stand with a constant head of water maintained above it. The rate of water flow through the sample is measured at intervals over 2-4 hours. Darcy's law is used to calculate the saturated hydraulic conductivity based on the water flow rate, cross-sectional area of the sample, length of the sample, and head of water. Hydraulic conductivity values are classified from very slow to very rapid.
The standard Proctor test is conducted to determine the optimum water content and maximum dry density of soil for compaction. Soil samples are compacted in layers in a standardized metal mold at different water contents using a rammer. The bulk density of each compacted sample is calculated and a curve is plotted of dry density versus water content. The water content corresponding to the highest dry density is the optimum water content. A penetration resistance test is also conducted using a Proctor needle to obtain the relationship between penetration resistance and water content.
The document provides instructions for conducting 12 geotechnical engineering experiments in the geotechnical engineering lab at B.V. Raju Institute of Technology. The experiments include determining Atterberg limits, field density via core cutter and sand replacement methods, grain size analysis, constant and variable head permeability tests, unconfined compression test, direct shear test, compaction tests, and CBR testing. Students must complete 8 of the 12 experiments listed. Instructions are provided for each experiment, including the aim, theory, apparatus required, and procedures to follow.
Data Communication and Computer Networks Management System Project Report.pdfKamal Acharya
Networking is a telecommunications network that allows computers to exchange data. In
computer networks, networked computing devices pass data to each other along data
connections. Data is transferred in the form of packets. The connections between nodes are
established using either cable media or wireless media.
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An In-Depth Exploration of Natural Language Processing: Evolution, Applicatio...
Permeability.pptx
1. Permeability of Soil
Why is it important to determine soil
permeability?
Soil permeability is the property of the soil to
transmit water and air and is one of the most
important qualities to consider for fish culture.
1
3. Permeability of Soil
3
• Permeability can be defined as the property of
the soil which enables the flow of water through
it.
There are voids in the soil, which if are
interconnected to each other, provides the path for
the flow of water through it.
4. Permeability of Soil
4
The coefficient of permeability depends on the
particle size and various other factors. Some typical
values of coefficient of permeability of different soils
are given in Table Soil Type Permeability in cm/s
Gravel 10 to 1
Coarse sand 1 to 0.1
Medium sand 0.1 to 0.01
Fine sand 0.01 to 0.001
Silty sand 0.001 to 0.0001
Silt 1 x 10-5
clay 1 x 10-7 to 1 x 10-9
5. Permeability of Soil
5
Laboratory Measurement of Permeability:
Constant Head Flow
Constant head permeameter is recommended for
coarse-grained soils only since for such soils, flow
rate is measurable with adequate precision.
As water flows through a sample of cross-section
area A, steady total head drop h is measured across
length L.
7. Permeability of Soil
7
Constant Head Flow
1. Permeameter mould, internal diameter = 100mm,
effective height =127.3 mm, capacity = 1000ml.
2. Detachable collar, 100mm diameter, 60mm height.
3. Dummy plate, 108 mm diameter, 12mm thick.
4. Drainage base, having porous disc.
5. Drainage cap having porous disc with a spring attached
to the top.
8. Permeability of Soil
8
Constant Head Flow
• Compaction equipment such as Proctor’s rammer
Constant head water supply reservoir
• Graduated glass cylinder to receive the discharge.
• Stop watch, A meter scale to measure the head
differences and length of specimen.
• Weighing balance accuracy 0.1g
• Filter paper.
9. Permeability of Soil
9
Constant Head Flow
Specimen Preparation
• Remove the collar of the mould. Measure the internal
dimensions of the mould.
• Weigh the mould with dummy plate to the nearest gram.
• Apply a little grease on the inside to the mould. Clamp
the mould between the base plate and the extension
collar and place the assembly on a solid base.
10. Permeability of Soil
10
Constant Head Flow
Specimen Preparation
• Take about 2.5kg of the soil sample, from a thoroughly mixed
wet soil, in the mould.
• Compact the soil at the required dry density using a suitable
compacting device.
• Take a small specimen of the soil in a container for the water
content determination.
• Remove the collar and base plate. Trim the excess soil level
with the top of the mould.
11. Permeability of Soil
11
• Clean the outside of the mould and the dummy
plate. Find the mass of the soil in the mould.
• The mould with the sample is now placed over the
permeameter. This will have drainage and cap
discs properly saturated
12.
13. Permeability of Soil
13
Constant Head Flow
Test Procedure
• Through the top inlet of the constant head
reservoir, the specimen is connected.
• The bottom outlet is opened and a steady flow is
established.
• For a particular time interval, the quantity of flow
can be collected.
14. Permeability of Soil
14
Constant Head Flow
Test Procedure
• Measure the difference of head (h) in levels
between the constant head reservoir and the outlet
in the base.
• For the same interval, this is repeated three times.
15. Permeability of Soil
15
The data that is obtained directly from the tests are:
Length (L) in cm
Area (A) in cm2
Constant Head (h) in cm
Discharge (q) cm3/sec = Q/t
Volume of water collected Q cm3 in t seconds
q = kiA or k = q/iA = q/(h/L)A = qL/(Ah)
Coefficient of permeability k = qL/(Ah) = QL/(Aht)
16. Permeability of Soil - Variable Head test
16
Total head h in standpipe of area a is allowed to fall.
Hydraulic gradient varies with time. Heads h1 and h2
are measured at times t1 and t2.
At any time t, flow through the soil sample of cross-
sectional area A is
18. Permeability of Soil - Variable Head test
18
Apparatus
1. Mould Assembly: The mould assembly including drainage base
and drainage cap which need to be conform to IS: 11209-1985
2. Compaction Hammer
3. Set of Stand Pipes: Glass stand pipes varying in diameter from 5
to 20 mm, suitably mounted on stand or otherwise fixed on wall.
4. Constant Head Tank: A suitable water reservoir capable or
supplying water under constant head.
19. Permeability of Soil - Variable Head test
19
Procedure
1. Connect the specimen to the selected stand-pipe through the
top inlet.
2. Open the bottom outlet and record the time interval required
for the water level to fall from a known initial head to a
known final head as measured above the center of the outlet.
3. Refill the stand-pipe with water and repeat the test till three
successive observations give nearly same time interval; the
time intervals being recorded for the drop in head from the
same initial to final values, as in the first determination.
20. Permeability of Soil - Variable Head test
20
The following values shall be recorded in the data sheet of
variable head permeability test:
Length of specimen (L)
Diameter of specimen (D)
Volume of specimen (V)
Diameter of stand pipe (d)
Area of stand pipe (a)
21. Permeability of Soil - Variable Head test
21
At temperature T of water, the permeability kT is calculated
using the following expression:
kT= ((2.30aL)/(At))Log10(h1/h2)
Where h1: initial head, h2: final head
t: time interval
a: cross-sectional area of the liquid stand pipe
A: cross-sectional area of the specimen
L: length of specimen.
雅虎竞拍
煤炉代买
paypay商城
乐天二手
日本亚马逊
乐天新品
ZOZOTOWN
