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This study includes adding chemicals to gypseous soil to improve its collapse characteristics. The collapse behavior of gypseous soil brought from the north of Iraq (Salah El-Deen governorate) with a gypsum content of 59% was investigated using five types of additions (cement dust, powder sodium meta-silicate, powder activated carbon, sodium silicate solution, and granular activated carbon). The soil was mixed by weight with cement dust (10, 20, and 30%), powder sodium meta-silicate (6%), powder activated carbon (10%), sodium silicate solution (3, 6, and 9%), and granular activated carbon (5, 10, and 15%). The collapse potential is reduced by 86, 71, 43, 37, and 35% when 30% cement dust, 6% powder sodium meta-silicate, 10% powder activated carbon, 6% sodium silicate solution, and 10% granular activated carbon are used, respectively.

Gypseous soils are considered one of the most problematic soils. The skirted foundation is an alternative technology that works to improve the bearing capacity and reduce settlement. This paper investigates the use of square skirted foundations resting on gypseous soil subjected to concentric and eccentric vertical load with eccentricity values of 4, 8, and 17 mm in 16 experimental model tests. To obtain the results by using this type of foundation, a small-scale physical model was designed to obtain the load–settlement behavior of the square skirted foundation; the dimension of the square footing is 100 mm × 100 mm with 1 mm thickness, the skirt depth (D s) was 0.5, 1, and 1.5B (where B is the footing width). The footing rests on dry gypseous soil with a relative density of 33%. The tests show that the gypsum content of the soil is 59%. The result shows that the highest bearing capacity for the square shape footing with D s/B = 1.5 subjected to concentric load results in an improvement ratio of 190%. For the eccentric load, with D s/B = 1.5, the increase in bearing capacity is about 120% at e = 8 mm when compared with using a foundation without a skirt.

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This literature review of research on evaluation performance of ring footing as well as circular footing and squaire footing that rest on gypseous soil treated with materials to improve its properties. Review the available experimental tests to calculate the bearing capacity and discover the behavior of ring footing rested on soil under load and investigate the relationship between (load, settlement) under the effect of the load as well as improving the properties of gypseous soil is the goal of this study. Ring footing is more cost-effective than other geometrical footing designs, its used in many applications, and it's critical to look into gypseous soil, especially since much of Iraqi areas are covered in it (by more than 12 percent). The gypsum in the soils leached out when the water arrived from (rain, rising water table, sewer, or another source), causing several difficulties and damage to the structures built on gypseous soil, thus the properties of these soils must be examined and addressed [ABSTRACT FROM AUTHOR]

Civil engineers are constantly developing innovative methods to improve the bearing capacity and reduce settlement of footing rest on the soil. The skirted foundation is one of the ways that civil engineers have devised to reduce settlement and increase the bearing capacity of footing rest on the soil. A skirted foundation can be more robust than traditional foundation types; its cost effect made it an alternative to a deep foundation in case of the low bearing capacity of the soil. Skirted foundations are usually used with offshore structures. The skirt prevents soil erosion since it prevents water from reaching the underlying soil. It works to confine soil between the skirt wall and make a resistance ageist sliding by skirt side. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study a series of shaking table tests were carried out to investigate the effect of tunnel model depth and direction of ground acceleration on the horizontal acceleration of tunnel model and soil beside it, ground surface settlement, and the dynamic earth pressure on the tunnel wall. Square tunnel model embedded in both dry and saturated soil (Karbala Sand). It subjected to three input sinusoidal motions 0.05g, 0.1g, and 0.2g. Two relative densities used, 30% for the upper layer and 70% for the lower layer. The results obtained indicate that the direction of seismic loading has significant effect on the horizontal acceleration of tunnel model. The increase of tunnel model depth lead to decrease the horizontal acceleration of tunnel model. While, the settlement of soil surface increases with an increase of tunnel model depth and ground acceleration especially at 0.2g earthquake loading. The change of direction of seismic loading leads to a small change in the settlement for dry soil. The results appear that dynamic earth pressure (DEP) was positive in dry soil and negative in saturated soil in all test. In saturated soil, the effect of direction of ground acceleration and depth of tunnel model on DEP in 0.2g is quite little. [ABSTRACT FROM AUTHOR]