A linear log d – log w model for the determination of consistency limits of soils

2001 ◽  
Vol 38 (6) ◽  
pp. 1335-1342 ◽  
Author(s):  
Tao-Wei Feng

A linear logarithm–logarithm model for the fall cone penetration depth versus water content relationship (flow curve) has been developed based on the results of an experimental study using the British fall cone apparatus. The fall cone flow curve is expressed by a simple equation with parameters m and c, which represent the slope of the flow curve and the water content at a penetration depth of 1 mm, respectively. For a soil, the flow curve can be determined by applying a linear regression analysis to at least four data points with penetration depths approximately evenly distributed between 25 and 3 mm. It is shown in this paper that both the liquid limit and the plastic limit determined from the linear logarithm–logarithm flow curve are in close agreement with those determined from conventional methods. A one-point method for determination of the liquid limit is developed from the model and is verified by applying statistical analysis to a large volume of experimental data.Key words: fall cone, laboratory tests, consistency limits, clays.

1991 ◽  
Vol 226 ◽  
Author(s):  
T.W. Wu

AbstractAn ac-microindentation technique, namely indenting with a small displacement modulation superimposed on an otherwise linear indenter motion, will be introduced. The basic principle and theory will also be illustrated by using a mechanical model to simulate the indenter behavior.Other than being as capable as conventional indentation, the ac-technique acquires the unloading slope simultaneously and continuously with the penetration depth and applied load during an entire indentation process. With this extra information, the conversion between the total depth and plastic depth can be executed right after a single indentation, and in turn the hardness as well as. contact modulus depth profiles can be calculated. This is in contrast to the conventional indentation technique where a group of indentations associated with different maximum loads are required in order to achieve the same purpose. Furthermore, it also avoids the subjectivity in the selection of the fitting portions from the unloading stage of an indentation curve to extract the unloading slopes as well as the plastic penetration depths.Another important advantage of using this ac-technique is the high sensitivity in detecting the indenter/surface contact. This advantage is very useful in the determination of the origins of penetration depths as well as in the investigation the evolution of the contact area, and both issues are very crucial in the microhardness calculations.The strain rate effect on the hardness measurements of a 1 μm thick Al-2%Si coating has been demonstrated by using the ac-technique. As the indenter loading speed increases from 2.5 to 10 nm/sec, the measured hardness of the coating can be increased from ∼20% to ∼80% depending on the penetration depth, and the shallower the penetration depth the larger the increment is. However, the contact modulus depth profiles remain unchanged for all the indentation rates.


UKaRsT ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 13
Author(s):  
Rekso Ajiono ◽  
Herlan Pratikto

Dalam bidang konstruksi Tanah adalah suatu media pijakan inti dari sebuah bangunan. Struktur Tanah yang sebagian banyak terdapat lempung didalam komponennya adalah bersifat Monmorillonite. Tingkat stabilitas tanah yang bersifat Montmorillonite terbilang kurang bagus terhadap daya topang infrastruktur bangunan. Cara stabilitas tanah pada penelitian berikut adalah dengan menggunakan abu daun pada variasi penambahan 5%, 10%, 15% dan 20% dengan melakukan pengujian Water Content dan uji gradasi pada struktur tanah asli yang digunakan sebagai sampel penelitian, Uji tanah sampel diambil dari area perumahan wilis indah kota Kediri yang bersifat Montmorillonite. Pada test uji stabilitas tanah adalah dengan menggunakan benda uji mix tanah montmorillonite dengan abu daun dengan melakukan uji Berat Isi, Batas konsistensi (Atterberg Limit) dan Pemadatan Tanah (Proctor). Pada hasil penelitian struktur tanah asli dikategorikan momoroillonite dan setelah ditambah ampas kopi pada penambahan divariasi maksimal sebesar 20%, nilai Liquid Limit naik menjadi 43% dan nilai Plastic Limit mengalami kenaikan menjadi 31,64%, sehingga index plastic dapat mengalami peningkatan menjadi 11,36%. Saat uji pemadatan dengan kondisi benda uji padat sempurna, berat volume kering tanah asli sebesar 6,72 gr/cm3 dan setelah ditambahkan abu daun sebesar 20% mengalami peningkatan berat volume kering menjadi 10,56 gr/cm3.Kata Kunci: Tanah, Abu daun, Stabilitas Tanah


1977 ◽  
Vol 14 (4) ◽  
pp. 571-581 ◽  
Author(s):  
R. Garneau ◽  
J. P. LeBihan

A large number of laboratory tests, carried out to determine index and physical characteristics of Champlain marine clays, using conventional testing procedures and the Swedish fall cone tests, have led to reliable relationships between the cone penetration and certain characteristics.The purpose of this study has been to establish a rapid method of estimating some index and physical characteristics of this clay. The method described in this paper allows the estimation of clay properties, such as liquid limit, compression index, preconsolidation pressure, undisturbed and remolded shear strength, sensitivity, water content, void ratio, and unit weight, within as little as half an hour and using a single undisturbed specimen. When testing according to conventional procedures, the determination of these characteristics takes several days or even weeks.This paper presents the method of estimation and the procedure used to establish the relationships between the results obtained by conventional methods and those derived using the Swedish fall cone.


2006 ◽  
Vol 45 (9) ◽  
pp. 1282-1290 ◽  
Author(s):  
Brad Baker ◽  
R. Paul Lawson

Abstract Ice water content in natural clouds is an important but difficult quantity to measure. The goal of a number of past studies was to find average relationships between the masses and lengths of ice particles to determine ice water content from in situ data, such as those routinely recorded with two-dimensional imaging probes. The general approach in these past studies was to measure maximum length L and mass M of a dataset of ice crystals collected at a ground site. Linear regression analysis was performed on the logarithms of the data to estimate an average mass-to-length relationship of the form M = αLβ. Relationships were determined for subsets of the dataset based on crystal habit (shape) as well as for the full dataset. In this study, alternative relationships for determining mass using the additional parameters of width W, area A, and perimeter P are explored. A 50% reduction in rms error in the determination of mass relative to using L alone is achieved using a single parameter that is a combination of L, W, A, and P. The new parameter is designed to take into account the shape of the ice particle without the need to classify the crystals first. An interesting result is that, when applied to the test dataset, the same reduction in rms error is also shown to be achievable using A alone. Using A alone facilitates the reanalysis and improvement of the determination of ice water content from large existing datasets of two-dimensional images, because A is simply the number of occulted pixels in the digital images. Possible sources of error in this study are investigated, as is the usefulness of first segregating the particles into crystal habits.


2017 ◽  
Vol 50 (2) ◽  
pp. 778 ◽  
Author(s):  
G. Kollaros

Specifications in European countries include a variety of methods for determining the liquid limit based on Casagrande type devices and on the fall cone penetrometer. The results of a comparative study of the liquid limits determined using these two fall-cone methods are presented for lime stabilized soil. Soil material sampled in the area of Evros Regional Unit has been stabilized with lime in order to enhance its engineering characteristics. The soil and the soil-lime mixtures subjected in Atterberg limit testing. The liquid limit values were correlated through a linear regression analysis with the rest of the consistency limits of both the natural soil and its mixtures with various lime contents. The correlation coefficients in all cases were high, with those referring to results obtained by the Casagrande method to be dominant. The comparison of liquid limit values determined by either method showed that there is a systematically good correlation between them, with the decrease rate in function of the lime content in the mixture to be more intense in the case of the drop-cone procedure. There is a need for a universal specification for the determination of the consistency limits. 


2021 ◽  
Vol 2 (2) ◽  
pp. 10-22
Author(s):  
Alfian Adie Chandra

The problem of the bearing capacity of the subgrade is one of the most important thingsconsidered in a planning and work of a civil building construction. This matterbecause the soil functions as a medium that withstands the load or action of the constructionbuilt on it. Changes in weather and temperature in the field are factors that makeunstable ground. Many stabilizations have been carried out using cement soil, howeverrequires no small cost and also the results of the implementation of the soil stabilizationrelatively short-lived. Therefore, this research was conducted using a mixture ofsirtu with mixed variations of 15%, 20% and 30%. More variety of mixThe added sirtu causes the water content to decrease which will make the power value decreasethe bearing capacity of the soil increases, the value of the plastic limit increases, while the value of the liquid limit and indexthe plasticity of the soil decreases.


2016 ◽  
Vol 846 ◽  
pp. 336-341 ◽  
Author(s):  
M.A. Llano-Serna ◽  
M.M. Farias ◽  
D.M. Pedroso ◽  
David J. Williams ◽  
D. Sheng

The material point method is a particle-based method that uses a double Lagrangian-Eulerian discretisation. This approach has proved its functionality for the simulation of large deformation problems. Such problems are frequent in geotechnical engineering, more specifically those related to penetration during pile driving and conventional in situ tests such as the Cone Penetration Test. The shallow laboratory fall cone test is considered in this paper. This test is widely used for the determination of the liquid limit of clays, but it is also used to study the relationship between penetration (h) and the undrained shear strength of clays (su). Simulations are verified against laboratory vane shear tests and fall cone tests performed on samples of kaolin clay at different moisture contents. Calibrations using a simple penetration-strength (h-su) model are made based on a single coefficient named the cone factor (K). The numerical results closely match both the experimental data and analytical solutions available in the literature.


2010 ◽  
Vol 47 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Kamil Kayabali ◽  
Osman Oguz Tufenkci

The undrained shear strength of remolded soils is of concern in certain geotechnical engineering applications. Several methods for determining this parameter exist, including the laboratory vane test. This study proposes a new method to estimate the undrained shear strength, particularly at the plastic and liquid limits. For 30 inorganic soil samples of different plasticity levels, we determined the Atterberg limits, then performed a series of reverse extrusion tests at different water contents. The plastic and liquid limits are derived from the linear relationship between the logarithm of the extrusion pressure and water content. The tests show that the average undrained shear strength determined from the extrusion pressures at the plastic limit is about 180 kPa, whereas the average undrained shear strength at the liquid limit is 2.3 kPa. We show that the undrained shear strength of remolded soils at any water content can be estimated from the Atterberg limits alone. Although the laboratory vane test provides a reasonable undrained shear strength value at the plastic limit, it overestimates the undrained shear strength at the liquid limit and thus, care must be taken when the laboratory vane test is used to determine undrained shear strengths at water contents near the liquid limit.


Revista CERES ◽  
2013 ◽  
Vol 60 (5) ◽  
pp. 715-721 ◽  
Author(s):  
Walter Francisco Molina Jr ◽  
Sônia Maria Stefano Piedade ◽  
Juarez Rennó Amaral

The soil penetration resistance has been used to represent the compaction situation and several authors have attempted to relate the cone index (CI) with the bulk density. The importance of using the CI as source of information for decisions in agricultural activities, livestock and forestry manner, has become increasingly larger, which requires more knowledge about the penetrometers and penetrographs behavior. This study aimed to verify, in controlled laboratory conditions, the influence of soil water content and cone penetration rate to obtain the cone index, when density variation occurs. The soil was compacted by compression through a universal press cylinder which was specially designed to produce the test specimens. Bulk densities were determined from samples taken from the test specimens and their moisture content. The CI values obtained were between 0.258 and 4.776 MPa, measured in 4 moistures and 7 soil densities with 3 penetration speeds. It was concluded that the determination of IC is strongly influenced by the soil moisture but the penetration speed variation, used in this study, was not sufficient to influence the IC determination. However, the decrease in soil water content may increase the sensitiveness to detect a variation in bulk density by the use of cone index.


2011 ◽  
Vol 328-330 ◽  
pp. 957-960 ◽  
Author(s):  
Yan Chun Tang ◽  
Gao Tou Meng

Based on analysis on the difference between the single and double bridge Cone Penetration Test and CPTU, through CPTU application research on the determination of soil type on Pearl River Delta, the advantage on exploring the thin sandwich by CPTU has been studied. The existence of thin sandwich on soft soil is important on design and construction of soft subgrade, and must be identified strictly on the exploration process; associated with the total cone resistance-penetration depth curve and the pore pressure-penetration depth curve on the determination of soil type, especially on the distinction between the sand soil and clay soil, the accuracy of CPTU is higher than the single or double bridge Cone Penetration Test; based on CPTU application research on Pearl River Delta, the determination of soil type by CPTU can be more accurate than the drilling way, and the advantage for exploring thin sandwich by CPTU can be more various. The achieved result can provide a foundation for further study for CPTU application research on engineering exploration.


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