scholarly journals Experimental Investigation of Square Footing Resting on Sand over Gypseous Soils

2020 ◽  
Vol 27 (1) ◽  
pp. 30-39
Author(s):  
Adnan Zedan ◽  
Heba Abbas
Keyword(s):  
Experimental Investigation ◽  
Relative Density ◽  
The Other ◽  
Layered Soils ◽  
Square Footing ◽  
Gypsum Content ◽  
Replacement Process ◽  
Sandy Layer ◽  
Relative Density Of Sand ◽  
Gypseous Soil

This study included (40) tests of loading a square footing (100*100 mm) resting on two layered soils (sand over gypseous soils) using a steel box with the dimensions of (900*900*500 mm). Gypseous soil was brought from Tikrit-University with gypsum content 61%. The tests were divided into two groups. The first groups included (4) tests for gypseous soil only by using the field and maximum densities (14.5, 18.75 kN/m3) respectively, without soaking and with soaking where gypseous soil lost a great value of its resistance. The second group included (36) tests of loading two layers of soil by replacing a layer of gypseous soil by sandy soil with relative density (30%, 60%, and 80%) and depths (B/2, B and 3/2 B). The results showed that the replacement process gave an improvement in the bearing capacity when the gypseous soil was compacted to field density and soaked with a relative density of sand (80%) while the other cases did not have any improvement. The results of loading the two layers of soil also show that the soaking of gypseous soil under the sandy layer affects on the resistance of sand through reducing it especially when the depth of sand was (B/2) this effect decreased gradually with increase in the depth of the sandy layer.

scholarly journals Experimental Pullout Capacity of Screw Piles in Dry Gypseous Soil

2021 ◽  
Vol 318 ◽  
pp. 01002
Author(s):  
Mahdi O. Karkush ◽  
Omar J. Mukhlef
Keyword(s):  
Relative Density ◽  
Offshore Structures ◽  
Pullout Capacity ◽  
Single Screw ◽  
Gypsum Content ◽  
Pullout Testing ◽  
D 20 ◽  
Pile Model ◽  
Supporting Structures ◽  
Gypseous Soil

Screw piles are widely used in supporting structures subjected to pullout forces, such as power towers and offshore structures, and this research investigates their performance in gypseous soil of medium relative density. The bearing capacity and displacement of a single screw pile model inserted in gypseous soil with various diameters (D = 20, 30, and 40) mm are examined in this study. The soil used in the testing had a gypsum content of 40% and the bedding soil had a relative density of 40%. To simulate the pullout testing in the lab, a physical model was manufactured with specific dimensions. Three steel screw piles with helix diameters of 20, 30, and 40 mm are used, with a total length of 500 mm. The helix is continuous over the pile's embedded depth of 400 mm. The results of tests revealed that decreasing the length to diameter (H/D) ratio resulted in a higher pullout capacity of screw piles and a lower corresponding displacement.

Effect of Cavities from Gypsum Dissolution on Bearing Capacity of Soil under Square Footing

2020 ◽  
Vol 857 ◽  
pp. 221-227
Author(s):  
Israa Saleh Hussein ◽  
Lamyaa Najah Snodi
Keyword(s):  
Bearing Capacity ◽  
Water Flow ◽  
Three Dimensional ◽  
Cavity Volume ◽  
Finite Element Program ◽  
Square Footing ◽  
Gypsum Content ◽  
Element Program ◽  
Three Dimensional Finite Element ◽  
Gypseous Soil

This study deals with cavities under square footing which resulted from gypsum dissolving due to water flow in gypseous soil. This process leads to collapse of soil structure and progressive compression. A model was developed for governing the mass-transport to assess the variation of gypsum content of the soil during dissolution by ground water flow then cavity formation was adopted. A general three-dimensional finite element program (PLAXIS 3D) was selected for numerical analysis method to generate the solution. The study included a number of variables and their effect on bearing capacity of gypseous soil such as (gypsum content, cavity volume and location). The cavity was represented as axis and plane cavity which has square section. The results show that the most dangerous case is found when the cavity locates at the center of footing base (Z/B = 0), where the bearing capacity decreased by (14, 37, and 69%) for (20, 30, and 40%) gypsum dissolving ratio respectively. Also, the bearing capacity decreased when the cavity volume increases due to increasing dissolution ratio. The effect of cavity became disappear after (Z/B = 4). While, when using plane cavity, there was no cavity at center of footing base (Z/B = 0) because it considered as a hole not cavity. When using plane cavity, the bearing capacity decreased by (28, 43, and 53%) for (20, 30, and 40%) dissolving ratio respectively when (Z/B=1). The effect of cavity on the bearing capacity would be disappear as the distance from footing center increase until it became disappear at (Z/B = 6 m). The plane cavity is more dangerous than axis cavity.

scholarly journals Behavior of Square Footing Resting on Gypseous Soil and Surrounded by a Sheet Pile Wall

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mazin Ali Hussein ◽  
Mahmood G. Jassam ◽  
Akram H. Abd
Keyword(s):  
Laboratory Model ◽  
Sheet Pile ◽  
Effective Protection ◽  
Square Footing ◽  
The Third ◽  
Gypsum Content ◽  
Different Depths ◽  
The One ◽  
Gypseous Soil ◽  
Sheet Pile Wall

Abstract Laboratory model is used in this study to investigate the behavior of centrally loaded square footing resting on gypseous soil, and surrounded by a sheet pile wall at a distance of 2B from the footing edge and extend in depth to 2B as well. During this study the soil were subjected to ten cycles of saturation and drainage at one-week interval to simulate heavy rainfalls or floods. It should be noted that the soaking water were added only outside the area surrounded by the sheet pile. Four points were chosen to detect gypsum solubility, three of them below the footing edge at different depths and one outside the sheet pile wall for comparison. It has been found that the dissolved gypsum below the footing is significantly less than the one outside the sheet pile wall. For each cycle of saturation-drainage the gypsum content is found to be reduced by 3 % and 0.8 % for the outsider point and for average of the three points respectively. Settlement during first cycle of saturation – drainage was twice as the second cycle and about four times of the third cycle. However, this first cycle settlement is about 25 % of the settlement of footing where no sheet pile wall is used. To sum up, the sheet pile wall found to be an effective protection to reduce the collapsibility of gypsum soil and to reduce footing settlement.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

scholarly journals Experimental investigation of vertical and horizontal reinforcement geotextiles in forest road pavement

2018 ◽  
Vol 64 (No. 7) ◽  
pp. 296-302 ◽  
Author(s):  
Dini Morteza ◽  
Nikooy Mehrdad ◽  
Naskovets Michael Trofimovich ◽  
Ghomi Alireza
Keyword(s):  
Experimental Investigation ◽  
The Other ◽  
Data Logging ◽  
Truck Traffic ◽  
Horizontal Structure ◽  
Forest Road ◽  
Vehicle Traffic ◽  
Road Pavement ◽  
Significant Difference ◽  
Experimental Survey

In this research, the results of an experimental survey on the measurement of vertical stresses are presented. Four treatments were used in this study such as combination of geotextile vertical and horizontal structure with dimensions of 5 × 5 and 10 × 10 cm, horizontal geotextile and the treatment without geotextile. Five sensors were installed in different hole locations and the lead of the truck traffic was transmitted by cables to data logging and recording devices to measure the pressure from vehicle traffic on the simulated pavement layer. Mean comparison of the treatments showed that the geotextile with vertical and horizontal structure and dimensions of 5 × 5 cm exerted the lowest pressure on the lower layers compared with the other treatments and there was a significant difference between the value of this treatment and the other treatments and that this treatment could significantly reduce the pressure of truck traffic on the forest road.

An experimentalist's view of the galvanomagnetic and thermomagnetic properties of potassium

1982 ◽  
Vol 60 (5) ◽  
pp. 679-686 ◽  
Author(s):  
R. Fletcher
Keyword(s):  
Experimental Investigation ◽  
Charge Density ◽  
Charge Density Wave ◽  
High Field ◽  
Density Wave ◽  
The Other ◽  
Detailed Structure ◽  
Precise Nature ◽  
A Charge ◽  
Thermomagnetic Properties

This paper provides a brief survey of the experimental and theoretical situation regarding the galvano- and thermomagnetic properties of potassium viewed within the context of the behaviour of other metals. Most of the data are consistent with various sample imperfections as being the major source of the anomalies that are found. However, the precise nature of the imperfections and the mechanism by which the imperfections produce the anomalies are not yet known. It is argued that the recently discovered detailed structure in the high field induced torque of K should be subjected to intensive experimental investigation before drawing any conclusions with regards to the possible presence of a charge density wave; the other magnetotransport properties offer little evidence either for or against such a possibility.

SURFACE SETTLEMENT INDUCED BY TUNNELING IN GREENFIELD CONDITION THROUGH PHYSICAL MODELLING

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Aminaton Marto ◽  
Mohamad Hafeezi Abdullah ◽  
Ahmad Mahir Makhtar ◽  
Houman Sohaei ◽  
Choy Soon Tan
Keyword(s):  
Relative Density ◽  
Physical Modelling ◽  
Diameter Ratio ◽  
Surface Settlement ◽  
Ground Movement ◽  
Outer Diameter ◽  
Tunnel Excavation ◽  
Tunneling Method ◽  
Relative Density Of Sand ◽  
Tunnel Shield

Geotechnical conditions such as tunnel dimensions, tunneling method and soil type are few factors influencing the ground movement or disturbance.  This paper presents the effect of tunnel cover to diameter ratio and relative density of sand on surface settlement induced by tunneling using physical modelling. The aluminum casing with outer diameter of 50 mm was used to model the tunnel shield. The size of the casing was 2 mm diameter larger than the tunnel lining. The tunnel excavation was done by pulling out the tunnel shield at constant speed with a mechanical pulley. The tested variables are cover to diameter ratio (1, 2 and 3) and relative density of sand (30%, 50% and 75%). The results demonstrated that the surface settlement decreased as the relative density increased. Also, as the relative density of sand increased, the overload factor at collapse increased. The surface settlement was at the highest when the cover to diameter ratio was 2.  It can be concluded that in greenfield condition, the relative density and cover to diameter ratio affect the surface settlement.

The population dynamics of metacercariae of Apatemon gracilis (Trematoda: Digenea) in three species of lake-dwelling leeches

Parasitology ◽  
1986 ◽  
Vol 93 (3) ◽  
pp. 517-530 ◽  
Author(s):  
S. M. Spelling ◽  
J. O. Young
Keyword(s):  
Population Dynamics ◽  
Relative Density ◽  
Sexual Maturity ◽  
Egg Production ◽  
Seasonal Pattern ◽  
Distinct Pattern ◽  
The Other ◽  
Mean Intensity ◽  
Density Values ◽  
Host Mortality

SUMMARYMonthly samples of the leeches Erpobdella octoculata, Glossiphonia complanata and Helobdella stagnalis were taken over a two-year period from an eutrophic, English lake to detect metacercariae of the trematode, Apatemon gracilis. In each cohort of each of the three leeches, prevalence was low in young individuals, rose to a peak in autumn/winter, and then declined until the cohort had almost died out; in E. octoculata and H. stagnalis a final brief increase occurred. Mean intensity and relative density values followed a similar seasonal pattern of change to that of prevalence in these last two species, but in G. complanata values fluctuated irregularly with no distinct pattern. The frequency distribution of the parasite in G. complanata was highly over-dispersed, but less so in the other two species. Infected E. octoculata reached sexual maturity. The parasite reduced egg production in G. complanata and H. stagnalis, but only by maximum values of 2·5 and 9% respectively. This reduction in fecundity is low compared to the subsequent high mortality, at 95% or more, of newly recruited young from as yet unidentified causes. Parasite-related host mortality was difficult to assess in young leeches, but there was some evidence for its occurrence in older leeches of E. octoculata and H. stagnalis. However, this is unlikely to play a prominent role in the control and regulation of lacustrine leech populations.

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