The Effect of Penetration Rate on the Strength of Remolded Clay and Sand Samples

1975 ◽  
Vol 12 (3) ◽  
pp. 336-348 ◽  
Author(s):  
Umesh Dayal ◽  
John H. Allen
Keyword(s):  
Penetration Rate ◽  
Velocity Ratio ◽  
Viscosity Coefficient ◽  
Analytical Relationship ◽  
Granular Soils ◽  
Cohesive Soils ◽  
Static Tests ◽  
Proportionality Constant ◽  
Penetration Tests ◽  
Penetration Velocity

The penetration rate effect on the strength of clay and sand was studied by constant velocity penetration tests performed with various velocities up to 2.662 f.p.s. (81.14 cm/s). The clay and sand targets were of various strengths and moisture contents. The construction of the penetrometer is similar to that used in static tests, and in each test the cone resistance, sleeve friction, and penetration velocity were recorded.Experimental results indicated that for granular soils the effects of penetration velocity on cone and sleeve friction resistances are insignificant, whereas, for cohesive soils, the increase in penetration velocity causes an increase in the cone and friction resistances. It is found that for the cohesive soils the ratio of dynamic to static strength is directly proportional to the logarithm of the penetration velocity ratio. The proportionality constant of this relationship defined as soil viscosity coefficient depends on the physical properties of the soil and the soil strength and its value increases as the strength of the soil decreases. For the tested soils various values of the soil viscosity coefficient are proposed for different strength ranges. The validity of the analytical relationship is established for penetration velocities ranging from 0.0044 f.p.s. (0.13 cm/s) to 18 f.p.s. (550 cm/s).

A Note on Friction Ratio

1975 ◽  
Vol 12 (4) ◽  
pp. 524-526
Author(s):  
Umesh Dayal ◽  
J. H. Allen
Keyword(s):  
Constant Velocity ◽  
Maximum Velocity ◽  
Granular Soils ◽  
Cohesive Soils ◽  
Moisture Contents ◽  
Different Types ◽  
Side Friction ◽  
Penetration Tests ◽  
Local Side ◽  
Penetration Velocity

Constant velocity penetration tests were conducted on the different types of soils ranging from gravelly sand through clay of various strengths and moisture contents. The tests were performed for various penetration velocities up to a maximum of 2.66 f.p.s. (81.14 cm/s). From the measured cone pressure and local side friction (sleeve friction), the friction ratio is calculated at various penetration velocities. The experimental results indicate that for granular soils the influence of penetration velocity on friction ratio is insignificant. In cohesive soils the increase in penetration velocity causes an increase in friction ratio which amounted to 80% at the maximum velocity used.

scholarly journals Grain-scale DEM study of open-ended pipe pile penetration in granular soils

2021 ◽  
Vol 249 ◽  
pp. 11007
Author(s):  
Michail Komodromos ◽  
Gaël Combe ◽  
Gioacchino Viggiani
Keyword(s):  
Distinct Element ◽  
Horizontal Stress ◽  
Granular Soils ◽  
Pipe Pile ◽  
Pile Shaft ◽  
Offshore Engineering ◽  
Pile Penetration ◽  
Penetration Tests ◽  
Shed Light ◽  
Number Of Particles

Open-Ended Pipe Piles (OEPP) are particularly popular in offshore engineering. An important feature of the installation of these piles is the rate with which soil enters the pile from the bottom, and its interaction with the internal pile shaft. The response of OEPP crucially depends on the occurrence of soil plugging, which can make the behavior of an OEPP similar to a pile of solid cross section. Plugging is generally attributed to arching effects in the soil; therefore, understanding this phenomenon requires an investigation at the grain scale. This is precisely the objective of this study, where the Distinct Element Method (DEM) is used to study the installation of an Open-Ended Pipe Pile in a Virtual Calibration Chamber comprising 128000 grains, under constant horizontal stress. Despite the relatively small number of particles, this numerical model is found to be able to reproduce several aspects of the mechanisms actually observed in thefield. The results are compared to those obtained from actual experiments of miniature pile penetration tests. Stress and strainfields that develop in the soil inside and outside the pile provide interesting data and shed light on the mechanisms at play during OEPP installation, especially as for the influence of grains interlocking.

scholarly journals Proposta de previsão da capacidade de carga à tração de estacas tipo hélice contínua em solos granulares

2020 ◽  
Vol 1 (48) ◽  
pp. 146
Author(s):  
Caio Cardoso Scipião ◽  
Alfran Sampaio Moura
Keyword(s):  
Bearing Capacity ◽  
Granular Soils ◽  
Specific Method ◽  
Uplift Capacity ◽  
Security Measures ◽  
Structural Element ◽  
Compressive Loads ◽  
Penetration Tests ◽  
Uplift Forces

Foundations projects must present security measures concerning the structural element and soil-structure system failure and acceptable displacements. In buildings it is very common to have foundations which are only subjected to compressive loads, however, in many of them, the foundations are submitted to uplifting forces, thus it is also necessary to verify the safety conditions regarding uplift capacity. In this context, this article evaluates the applicability of specific and non-specific methods for estimating the uplift bearing capacity of continuous flight auger piles in granular soils. In addition to that, a method was developed in order to estimate the ultimate uplift capacity of these pile types. In order to so, this research was based on 97 Standard Penetration Tests (SPT), and 12 continuous flight auger piles in granular soils subjected to the uplift forces. Among the evaluated literature methods, the specific method that presented the best agreement was Meyerhof and Adams (1968), and the non-specific one was Meyerhof (1953), both with approximately 65% higher values, in average, than the reference values and with great scatter. On the other hand, the developed method presented good agreement and lower scatter, establishing an alternative for the determination of uplift bearing capacity of continuous flight auger piles in granular soils.

Rate-controlled cone penetration tests in permafrost

2005 ◽  
Vol 42 (1) ◽  
pp. 184-197 ◽  
Author(s):  
Sylvie Buteau ◽  
Richard Fortier ◽  
Michel Allard
Keyword(s):  
Active Layer ◽  
Penetration Rate ◽  
Load Capacity ◽  
Creep Behaviour ◽  
Homogeneous Layer ◽  
Cone Penetration ◽  
Creep Tests ◽  
Cone Penetration Tests ◽  
Rate Controlled ◽  
Penetration Tests

Cone penetration tests (CPTs) were carried out in the summers of 1999 and 2000 in a permafrost mound near Umiujaq, in northern Quebec, Canada, to study the cryostratigraphy and assess the creep behaviour of permafrost. A new linear pushing system using an actuator technology was specifically designed and developed to accurately control the penetration rate of the cone in the permafrost. This system has a load capacity of about 113 kN at a maximum penetration rate of 1.5875 cm/s and a stroke of 120 cm and can provide constant penetration rates as low as 4 × 10–6 cm/s. It can be disassembled in pieces for easy hand transport and use in remote locations. Two different types of CPT were performed in the permafrost mound: stratigraphic profiling and creep test. The first type is a quasi-static CPT at a penetration rate of 0.1 cm/s, providing a stratigraphic profile of permafrost in terms of the measurement of penetrometer sensors as a function of depth. The second type is a series of quasi-static CPTs at incremental rates of penetration, from 10–4 to 10–2 cm/s, carried out in a homogeneous layer to study the creep behaviour of permafrost. Five distinct zones (unfrozen and frozen active layer, permafrost, cryotic but unfrozen ground, and perennially noncryotic ground) can be identified in the stratigraphic profiles. The creep exponents calculated from the creep tests range from 12 to 35 for the ice-poor frozen active layer and from 4 to 11 for the ice-rich permafrost. Key words: cone penetration test, permafrost, rate-controlled, creep behaviour, cryostratigraphy.

scholarly journals IN VITRO PENETRATION TESTS OF TRANSETHOSOME GEL PREPARATIONS CONTAINING CAPSAICIN

2017 ◽  
Vol 9 ◽  
pp. 116 ◽  
Author(s):  
Nuraini Azizah ◽  
Erny Sagita ◽  
Iskandarsyah Iskandarsyah
Keyword(s):  
Thin Layer ◽  
Penetration Rate ◽  
Entrapment Efficiency ◽  
Penetration Test ◽  
Franz Diffusion Cell ◽  
Layer Method ◽  
Thin Layer Method ◽  
Gel Preparation ◽  
Penetration Tests

Objective: Capsaicin is an active compound found in chili pepper and has been shown to have analgesic, antioxidant, anticancer, and anti-obesityproperties. To improve its penetration into the skin, capsaicin was prepared in a transethosome vesicle. Importantly, transethosomes are vesicles thatconsist of phosphatidylcholine, surfactant, and ethanol. In this study, capsaicin was prepared in a transethosome vesicle using two different methods:Direct transethosome formation and thin layer hydration. The aims of this study were to determine the effects of various methods of transethosomeformation on capsaicin characteristics and to evaluate the penetration capabilities of transethosome capsaicin gel.Methods: Ultimately, transethosome formation via the thin layer method yielded more favorable characteristics; these formations had particle sizesof 174.9±2.02 nm and an entrapment efficiency of 84.85±1.15%. The transethosome suspension was then developed into a gel formulation using 1%carbomer. An in vitro penetration test was performed using a Franz diffusion cell of mice abdomen skin, and the performance of the transethosomecapsaicin gel was compared to that of the standard capsaicin gel.Results: Penetration rate of capsaicin from either the transethosome gel preparation and the standard gel substance was 1549.68±49.6 and846.05±10.1 μg/cm2, respectively.Conclusions: According to these results, it can be concluded that gel preparations containing transethosome increase capsaicin penetration into theskin.

scholarly journals Pile Load Capacity – Calculation Methods

2015 ◽  
Vol 37 (4) ◽  
pp. 83-93 ◽  
Author(s):  
Bogumił Wrana
Keyword(s):  
Load Capacity ◽  
Cohesive Soils ◽  
Calculation Methods ◽  
Cohesionless Soils ◽  
Short Term ◽  
Pile Capacity ◽  
Static Tests ◽  
Capacity Calculation ◽  
Foundation Pile

Abstract The article is a review of the current problems of the foundation pile capacity calculations. The article considers the main principles of pile capacity calculations presented in Eurocode 7 and other methods with adequate explanations. Two main methods are presented: α – method used to calculate the short-term load capacity of piles in cohesive soils and β – method used to calculate the long-term load capacity of piles in both cohesive and cohesionless soils. Moreover, methods based on cone CPTu result are presented as well as the pile capacity problem based on static tests.

Modified Standard Penetration Test for Drilled Shaft Design in Weak Fine-Grained Rocks

2021 ◽  
pp. 036119812110378
Author(s):  
Timothy D. Stark ◽  
Ahmed K. Baghdady ◽  
Abdolreza Osouli ◽  
Heather Shoup ◽  
Michael A. Short
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Penetration Rate ◽  
Standard Penetration Test ◽  
Drilled Shafts ◽  
Penetration Test ◽  
Weak Rocks ◽  
Fine Grained ◽  
Linear Slope ◽  
Penetration Tests

Standard penetration tests (SPTs) have been used to estimate strength parameters of soils and weak rocks when it is difficult to obtain high-quality samples for laboratory shear testing. SPTs require 45 cm (18 in.) of split-spoon sampler penetration to determine the blowcounts per 0.3 m (1 ft), which is difficult to impossible to obtain in weak rock, that is, intermediate geomaterials. As a result, a modified SPT is presented here for sampler penetrations less than 45 cm (18 in.) in weak rocks. This new procedure is termed the modified standard penetration test (MSPT) and uses the penetration rate, not the sum of penetration blowcounts per 0.3 m, to estimate the unconfined compressive strength for the design of drilled shafts in weak fine-grained rocks. The penetration rate is the inverse of the linear slope of the penetration depth versus blowcount relationship. With this new test and interpretation procedure, 45 cm (18 in.) of sampler penetration is no longer required to estimate the unconfined compressive strength of weak rocks. An empirical correlation between MSPT penetration rate and laboratory-measured unconfined compressive strength is presented here for weak Illinois shale. This correlation could be used to estimate the unconfined compressive strength for the design of drilled shafts in weak rocks.

scholarly journals Effect of Temperature and Prewetting for Ice Penetration with Sodium Formate

2020 ◽  
Vol 2674 (6) ◽  
pp. 140-150
Author(s):  
Mateusz Piotr Trzaskos ◽  
Alex Klein-Paste
Keyword(s):  
Waiting Time ◽  
Digital Image Analysis ◽  
Penetration Rate ◽  
Sodium Formate ◽  
Effect Of Temperature ◽  
Test Results ◽  
Penetration Process ◽  
Constant Rate ◽  
Different Temperatures ◽  
Penetration Tests

Granular sodium formate (NaCOOH) is a popular deicer used at airports. It is mainly used to weaken compacted snow/ice and thereby facilitate mechanical ice removal. Earlier research has developed a set of methods quantifying deicer performance, but linking these test results to operational guidelines is difficult. The main objective of this study is to increase the knowledge of how temperature and prewetting affect the ice penetration performance of granular sodium formate. A new method to evaluate the development of ice penetration process is presented here. Ice penetration tests were performed with single grains on large, optically clear ice cubes, and digital image analysis is used to quantify the initial waiting time, penetration rate and –depth, and melted volume. Eighteen tests including dry and prewetted sodium formate grains were performed at three different temperatures (–2°C, −5°C, and −10°C). Prewetting reduced the initial waiting time (the time it takes before the particles started to penetrate) by a few minutes at −10°C, but at higher temperatures, this reduction was insignificant. The particles penetrated the ice at a constant rate. At −10°C, the particles penetrated at 10–15 mm/hour, while at −2°C this speed is about five times higher. Prewetting does not seem to have a clear beneficial effect on the penetration rate. Suggestions are given on how to capture the results from this study into operational guidelines for deicing operations at airports, using sodium formate as deicer.

scholarly journals Investigation of the impact interaction of pelleted seeds with the soil environment

2021 ◽  
Vol 875 (1) ◽  
pp. 012023
Author(s):  
M N Lysych ◽  
L D Bukhtoyarov ◽  
M L Shabanov
Keyword(s):  
Surface Layer ◽  
Penetration Rate ◽  
Interaction Model ◽  
Cohesive Soils ◽  
Soil Environment ◽  
Discrete Elements ◽  
Depth Of Penetration ◽  
Impact Interaction ◽  
The Impact ◽  
Coated Seed

Abstract The issues of studying the impact interaction of seeds with the soil environment by the method of discrete elements are considered. The main parameters of the used virtual stand are described and a brief description of the interaction model is given. As a result of the study, the depth of penetration of the seed, its displacement in the horizontal plane and the greatest depth of the crater were obtained. Analysis of the data showed that on unbound and loosely bound soils, a penetration rate of 50 m/s is sufficient for almost 100% penetration into the surface layer without noticeable displacement of the pelleted seed. On medium cohesive soils at a speed of 50 m/s, stable seed penetration is not ensured. The probability of its release is about 10%. At speeds of 75 m/s, almost 100% penetration into the surface layer is provided without noticeable displacement of the coated seed. On cohesive soils at speeds of 25 m/s, the seed is always ejected from the crater over a considerable distance. At a speed of 50 m/s, the probability of seed ejection is reduced to 30% and at 75 m/s to 10%.

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