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Soil Compaction - Science topic
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Questions related to Soil Compaction
Is the number of passes to control the quality of compaction too extensive?
Compare and contrast the different methods for assessing soil compaction, such as bulk density measurements, penetrometer tests, and visual assessments. Evaluate the strengths and limitations of each method, and their suitability for different soil types and land uses.
Describe the physical and chemical changes that occur in compacted soils, and the factors that determine the extent of compaction.
please share statistical data to support answer to my query
I would like to create artificial compaction on soil which is covered by special plant species.
Which tools and/or formulas can be used?
We are trying to get the best compression and consolidation in making Compressed Earth Blocks. Any suggestions on how to optimise the soil composition to get best packing density will be most appreciated.
I need to know what tillage systems out there cause the least soil compaction. It'd be great if there were references I could cite. I want to compare tillage systems and how much soil compaction they cause (if that would be possible).
As a function of dimensions of real projects?
Let me introduce myself, my name is Cindy. I am a graduate student and I'm currently study soil organic carbon in Mangrove Forest.
I would like to know if it is possible to measure dry bulk density in disturbed soil (sediment was taken in depths 0-15 cm and 15-30)? The condition was soil compaction occurs, I only able to took 300 gr wet sediment from each interval for analysis, I didn't take the rest due to transportation difficulties.
Hence, the volume of sediment will be using this equation
sediment volume = (weight dry sample/sediment particle density)+(weight wet sample-weight dry sample) (Avnimelech et al., 2001)
Many researchers have given the values of OMC and MDD for bentonite based buffer materials corresponding to heavy compaction (higher compaction energy).
Hi there,
what is (are) the benefit(s) of drawing the zero air voids with the compaction curve(s) ?
Thank you
QUESTIONS
1) It is known that anything that is overturned is screwed onto something solid to prevent it from tipping over.
Why civil engineers do not screw the sides of the walls on both sides, with the ground?
The overturning of the walls deforms beams and walls until it breaks them;
Do you like to break concrete?
2) Bending is a second deformation factor that breaks the cross sections of the bearing elements.
It is known that the bilateral pre-tensioning of the sides of the walls when they have suitable cross-sections eliminates the bending.
A combination of strong ground anchorage and at the same time pre-tensioning of the sides of the walls from their upper levels with tendons without relevance would stop overturning and bending which are the only causes of deformation and we know that deformation and failure are interrelated concepts.
Do you want distortion and failures?
3) Intersecting
If in the cross section of the wall we impose compressive intensities of 70% of the breaking factor, we increase the strength of the cross section by 40%.
Why do you use the mechanism of relevance as the main reinforcement and not tense walls?
4) We all know that deformation creates inelastic failure.
We mentioned the overturning of the wall and the bending of its trunk as causes of deformation and failure of all load-bearing elements.
However, deformation and even very serious can occur due to inhomogeneous subsidence of the soil.
The ground is inhomogeneous, by nature, with different support strengths at each base.
Soil sampling is required at each base foot, and if necessary soil compaction is required to increase the soil's ability to support the base.
However, due to cost, it is rarely applied and if it is applied, it is done only in great projects.
5) The non-prestressed connection of the sides of the walls with the ground diverts the seismic intensities, leading them on the cross sections.
The prestressed connection of the sides of the walls to the ground from the top level with unrelated tendons diverts the seismic intensities, leading them into the ground.
Why not apply this design?
No more excuses.
The absolute seismic system and the method that follows ensures little deformation and no failure as it controls the overturning and bending of the wall, increases the resistance of its cross-section to cut, ensures sample ground control before the construction of the project, and creates a very strong support strength of construction after compacting the foundation soil.
These are all fundamental laws of engineering, and you continue to design wrong.
I was wondering if there are any specific guidelines for the preparation of artificial soils in laboratory. In general we tend to add some different soils and make a blend of a new soil with distinct properties but somewhat corresponding to the parent material. Is any research available on the preparation of the same apart from use.
Assuming other factors non-limiting crop yield, focusing on soil physics, and looking for indicators of soil physical quality: can the degree of compaction (Bulk density/maximum or reference Proctor bulk density) be a universal indicator for crop yield?
How to set the sampling point reasonably and effectively to ensure that the geological statistical method can effectively analyze the spatial distribution characteristics of the compaction quality of the soil?
Hello everyone!
I have been doing Level 1 Inspection & Testing for Soil Compaction in the field. The compacting material is basically, CLAY. I use nuclear gauge to measure the field density and moisture.
I wanted to have the expertise suggestion on "how can we say if the moisture is OK or NOT or simply if the moisture that is used for compaction is within the design limit like +_2% or +-3% of OMC". I usually, use this feel method by hand but that is way too confusing to tell and it's subjective. Yes, there is one method to tell that is carrying out one dummy test, however, by the time the dummy test finishes the lifts would be laid and compacted.
So, I was wondering if there are any suggestions in this regard from the experts. Even if the method is feel based, I shall be thankful to have a bit more explanation so that I can implement in the field from next time.
Thanking you in advance.
Sumit Maskey
I compacted unbound aggregates at optimum moisture content and then let it dry in the oven for one day. The repeated load triaxial test was carried out on this sample in which I faced a weird behavior (please find the attached figures). The permanent deformation initially increases with a high rate and then its rate decrease slowly and finally it has a negative displacement (like expansion).
This behavior only happened in dried samples and the lower stress conditions (1.59 KN and 1.767 KN deviatoric stresses and 120 and 41.7 confining pressures). These samples have normal behavior, the permanent deformation keep increasing with load cycles, at higher loading environment.
I appreciate your time.
Which statistical test is appropriate to test the following hypothesis?
H01: There is no difference in soil compaction across all locations (e.g., Location A, B, C, D, and E). No zeros.
H02: There is no difference in the total number of small mammal burrows across all locations (e.g., Location A, B, C, D, and E). Many zeros.
Each location consists of 7 plots that are located apart from each others and each plot is divided into quads. burrows are counted within each quads. therefore, enormous number of quads have zero counts. Sample size are not equivalent and data are not normally distributed.
Since the variable is independent, I am thinking of using multiple Mann-Whitney U test to test my hypothesis:
burrows in A versus burrows in B
burrows in A versus burrows in C, etc.
I will really appreciate your help
I mean after doing the compaction practice in various water contents and determining the dry density corresponding to each water content, what would be the equation of the resultant compaction curve? Assuming that there should be only one optimum water content, I think the quadratic curve can be the best option to fit the bell shaped results. However, I could not find anything in the literature (the compaction curve is drawn without presenting the equation or a line simply connected data).
I was wondering if you could introduce me any reference about this matter.
It is a matter of great importance to me to determine the optimum moisture content consistently for all of my materials.
I attached my data and the quadratic curve passing through them. could you please let me know what is the optimum moisture content in these compaction data series and what is the compaction curve for them?
These are the questions I faced in my literature review I could not find an answer for them. Just for the record, I am going to do the CBR test on laboratory compacted base materials in the pavement.
1- In which moisture content and dry density this test is accomplished (generally for the scientific purpose). I mean, CBR can be employed directly after the compaction or after soaking in water for four days. Should the CBR test be done with various moisture content? Should it be done in 95% of MDD (as the compaction in field is usually 95% of compaction in the lab)?
2- What is the number of layers in the compaction process (if the vibratory hammer is used for the compaction)? 2 or 3 layers?
3- What would be the weight of surcharges if the pavement design includes an asphalt layer of 10 cm and a basecourse of 30 cm and the materials are to be used in the base layer?
4- While soaking aggregates in water, what should be the elevation of water above the sample?
Kind regards,
I need research articles on management of compaction of soils testing 3, 4 or more years. Significance differences between treatments is I´m looking for.
What do you think that are the effects and results of testing ?
Based on the New Zealand standard the specimen height should be 125- 127 mm. My question is that what if the resultant height of the sample after the compaction was more than or less than this amount. I asked it because there is a height correction in Marshal compaction method of Asphalt materials. I thought there should be something for the compaction Unbound Materials.
I'm looking for any labs working on these topics, articles or tools allowing to measure such data, more especially in agriculture.
We planned to take some samples from the area where wheat is to be grown in future. The area was laser levelled recently and not cultivated for some time.
It was very hard to take soil samples and the soil was very dry too (it should be at field capacity I believe).
Now, what strategies should be used to improve soil conditions for easier sampling?
Now i know that soil structure is destroyed resulting from activities of constant soil compaction (example vehicles, humans or animals going over a piece of land regularly) thus leading to loss of vegetative cover of the soil (making the soils bare). But when the area that lost its vegetative cover due to constant soil compaction is left to fallow over time without any interference/hindrance. The soils recover and grasses, weeds that could not withstand or survive in such soils begin to blossom and flourish
In soil compaction test, if a test result exceeds 100%, should engineers accept the result?
Hello every one,
I want to conduct direct shear test on rubber recycled products such as tire chips. I studied different articles that referenced ASTM D 3080 for doing direct shear test on these particles. According to this standard, compacted specimens shall be prepared using compaction method, water content, and unit weight. I suppose proctor compaction test is not correct way to understand how much to compact rubber particles in shear box. If anyone has experience or references in the direct shear tests on the rubber particles, please share it.
Many thanks.
Hello all,
My master thesis is on soil compaction simulation using DEM and for calibration of the contact model, I use Oedometer test. I simulate the Oedometer test and compare it with experimental values. The material properties of the calibrated oedometer simulation is then used in the soil compaction simulation. In Oedometer test, I use particles of radius 1mm. However, to reduce the computation time in soil compaction simulation, I scale the radius of the particles 10 times the original value(i.e. 1cm). Therefore. I should also scale up the material property values. I would like to know whether there are any relationship between the radius of the particle and the material properties like stiffness, friction coefficient etc. Thanks in advance.
Soil organic matter (SOM) is renowned for being the best indicator of soil quality, due to its capacity of improving stability and sustainability of agricultural and forest systems, as well as the fact it is sensitive to changes caused by agricultural practices such as soil tillage, soil compaction, erosion, liming, within others. However, the simple measurement of the total SOM (Walkley-Black, Yeomans & Bremner, dry combustion method - CHNS/O Analyzer) has not been sensitive enough to detect small changes in the soil. Thus, many SOM fractionation techniques have been used for this soil quality diagnosis purpose, such as SOM light fraction, SOM heavy fraction, carbon of microbial biomass, etc. However, most of these methods are expensive and difficult to be performed in large-scale monitoring programs. So I wonder if you know among the SOM fractions, which one(s) are those with better correlation or sensitivity to soil disturbance due tillage or crop system? Which of the SOM attributes would you recommend to be monitored in the long term programs, considering the operational feasibility (field soil sampling and lab analysis) and low cost?
What young's modulus could I adopt for colluvium/talus deposit (Silty sand with some stone blocks, Nspt= 5 - 20)?
The layer is 20 m height, slope angle 15°
And about Mohr-coulomb strength parameters, C and Ø?
Hello all, we want to restrict the lateral displacement of diaphragm wall. Due to the vicinity condition, we cannot use tie back anchors. In this regard, we offer T type diaphragm walls, however, this proposal are not cost effective. Anyone has another suggestion. Your help is greatly appreciated.

I have come across work of P.J. Yoder (1980) (A strain-space plasticity theory and numerical implementation). He made a strain-space equivalent to pure plastic Coulomb model. His model has the following benefits (according to Yoder P.J.):
- Return mapping is eliminated (A very provoking statement, but he shows the maths behind it as well as detailed comparison of simulation results).
- Global stiffness matrix inversion count is reduced (significant step forward, for dynamic / cyclic loading application)
Despite dramatic increse in computation efficiency, Yoder's work did not go mainstream. (perhaps you can you spot why?)
I am intrigued by his work as during recent triaxial testing we were able to control sand stiffness through controlling applied strain (deformation) history. Yoder P.J. has explicitly called for a "rationale to the strain space problem", and we appear to have found the missing experimental "rationale" .
We found strain (not stress) dependant soil patterns, which capture and allow full control over loss and recovery of drained sand stiffness. Also, post-liquefaction soil stiffness recovery, and we can impose post-liquefaction soil state during drained loading. We seem to be closing the gap between drained, undrained and partially drained sand, but the new findings explicitly call for a strain-space plasticity formulation.
Any input is greatly appreciated. Any links to strain-space models or strain-dependant observations of sand (such as liquefaction charts by R. Dobry, or plastic spin (strain) tenstor by Y. Dafalias). This topic is not covered by "mainstream" geotechnical curriculum, thus I don't expect many answers. But every answer and question on the rare subject is appreciated.
I want to measure the suction for an unsaturated material in a triaxial testing device. The suction tension for the material should be less than 1 MPa according to a small literature review I conducted. I know that there developments which use an osmose method. Are there good pressure transducers which are also able to measure the suction?
Another question is if the applied confining pressure will superimpose the suction tension.
Hi !!
I am working on Stability of unsaturated soil slopes due to infiltration, but I have convergence and numerical oscillation problems … This oscillated pore-water pressure distributions do not appear realistic, as they indicate drying of the soil, which is unlikely with an influx boundary condition.
Has anyone had similar problems?... Is there a relationship between the element size and the time step, that allows me to solve these problems?
Thanks for your help.
hii
hii
I happened to find in some journals as well as for my thesis that the ultimate uplift capacity of pile groups increased drastically when the pile dimension changed from intermediate to long pile (in my case as L/D changed from 24 to 34 the ultimate uplift capacity changed from 148N to 300N whereas for L/D 14 its juz 50N) what could be the possible explanation for the above behaviour??
Hello
Does anybody have an idea why do we use 25 blows in the standard compaction test ?
As well as why do we compact with 3 layers ?
thanks
The image provides test results classifying the soil.
Thanks

According to classical soil mechanics we generally consider the distribution of stress caused by a uniform surcharge loading, to stay constant along with depth. However, the stress distribution caused by a spread footing is considered to decrease with depth (generally becomes around 10% of contact pressure at 2B and 4B for square and strip footing respectively).
While designing an excavation retaining system with an adjacent building resting on strip footings, a common practice is to consider the building load as surcharge load (i.e. having an earth pressure diagram with constant abscissa). If this assumption is correct, then how is such earth pressure diagram different than earth pressure caused by a uniform surcharge (e.g. overburden extending to infinite extents).
Or in other words, how is the earth pressure on a retaining structure caused by an adjacent strip footing different than the earth pressure on the same retaining structure due to an adjacent surcharge load?
I don't know of many farmers routinely employing a field-wide evaluation of soil compaction, but when I do it's always wtih a penetrometer. Some sample a few points and believe that behavior reflects the whole area (a true statistical inference error, in my opinion). Others take samples not paying attention to soil moisture. I don't know, isn't there a better option or instrument?
Do these practices make soil aggregates even less stable? What else could be employed in order to fully reverse soil compaction, if that'd be even possible?
And, if so, why are they not effectively replacing tire tractors?
What changes can one make to their crop system in order to minimize soil compaction? Is there a paper/review addressing these measures?
I want to evaluate failure of slope in a shale formation but get faced with continuous washing of the slope face due to high incidences of rainfall.
Hello Dear Engineers
I need the data points of Volumetric strain vs. effective shear strain by Tokimatsu and Seed (1987), This curves used in liquefaction computing of soils.
I Found the paper and image of the curve and attached here but I couldn't found any data points.
Would you please provide me with the data points of this curves?
Thanks
Yours faithfully

I'm designing a benchtop experiment for a soil physics class. Students will use a small-scale soil penetration resistance probe to assess soil compaction. I have soil pots I wish to compact to known compaction levels. Question is: How?
tiles dust and lime are effective to increase the shear strength of alkaline soil
We have a dam embankment and it has been affected by dispersive phenomenon in the laboratory scale test and the process continues still today in all borrow sites. (We cannot change the borrow site)
I want to asses this internal erosion process (rates of subsidence and detachment of soil particles). I will be very grateful if you could recommend some applicable case studies for this problem!.
Regards,
I would like to know the compactive effort (size of the rammer, height of dropping and number of blow) to use to remould disturbed soil sample into its natural state in other to carry out remediation of contaminated soil in the laboratory.
I want to model the tunnel long-term deformation in soft soil with soft soil creep model in Plaxis 2D
I did some compaction tests with variations of PP fibers. As the aspect ratio decreased, the OMC increases. Is it possible, or should I repeat my tests?
I am studying the unsaturated soil compression, but I found the degree of saturation of soil did not change with the vertical loading 10Kpa. I think maybe I did not set the right the water level. Could you give me some advice about the water level setting?
I need to model the porosity that will be encountered during compaction of particles consisting of different shapes (not spherical) as determined during SEM analysis.
Ng and Pang (2000) stated that increasing the surcharge causes increasing the air entry value in SWCC, but I think it is reverse because increasing the surcharge will decrease big pores of a soil. What is your point of view?
Sometimes I am confused about permeability and diffusion during drying of food material.