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Natural soil is exposed, like other elements of the construction, to significant changes in temperatures are sources of forest fires or volcanic eruptions or natural bulky. Usually, accompanied by significant changes in temperatures of up to more than 300 degrees centigrade. Therefore, the need arises to study the effect of burning clayey soils, on the grain distribution and distribution of particleboard intricacies and atterbering limit and soil classification, in addition to the direct impact on the variables for the design of foundations such as the cohesion of the soil. The soil used was naturally clayey soil brought from Diyala province with (Liquid limit=56%, Plastic limit=51%, Specific gravity=2.59, the soil is classified as OH (Organic clays of medium to high plasticity). The soil was burned at different temperatures (75- 150- 300- 600°C) using special oven for burning at high temperature, the study was directed to investigate the effect of repeat arson for each grade and study changes in soil properties and distribution particleboard and suitability of the construction. The study showed basic change in the particle distribution and Atterbering limits which means changing the engineering properties for the design of foundations construction which indicates the importance of this types of research and potential development to expand in this area and develop ways to put construction solutions for such cases. A reduction percent in plastic limit was 20% and 26% at the end of the fourth cycle at 300oC and 150oC, respectively.

The presence of salts in soil may cause severe problems to structures constructed on it, because of the high dissolution of salt particles when subjected to water from any source. The primary objective of this study is to investigate the behavior of single footing over different percentages of sabkha soil (5%, 10%, 20%, and 40%). A laboratory model, manufactured locally was used for this study. The sabkha soil is prepared by mixing ordinary soil with specified quantities of sodium chloride salt to have different percentages of salinity. The footing used is a 75mm diameter circular steel plate and 20mm thickness and holds fixed stress, with the aid of a loading frame which in turn is attached to a firm table. Dial gauges are attached to the fixed table and placed on the footing, to record settlement with time. The study includes also the effect of cement and lime addition with different percentages(1%, 3%, and 5%), on the collapsibility of sabkha soil. Mixing sabkha soil with 5% of cement will reduce collapse potential (S/B%)* upon wetting, by 97%. While mixing sabkha soil with 3% lime will reduce collapse settlement by 47%, On the other hand, mixing sabkha soil with 1% cement slurry increases the collapsibility by 3%. This study also shines the light on the effect of compaction on the properties of sabkha soil. The collapse potential (S/B%)* was reduced by 50% when increasing the compaction of sabkha soil model from 17.7 to 19 kN/m3.

The land scape is subjected to higher temperature during the last three decades became of "Globule warming", which became high evaporation of surface water, in addition to the increase in salt content , because of the unaffected irrigation way, of planets and the increase in the capillarity action which contribute with this process. This may led to the dissolution of salts inside soil and its appearance on the ground surface, with different depths. The NaCl salt is one of the most common salts presence in widely areas in Iraq, which has high dissolution rate in water. The problem of such soils appear when subjected to miniaturization from any source, resulting high dissolution rate of the salts in side soil skeleton, which lead to the weakening of soil, cavities may appear inside soil layer, and so it may led to failure of structures constructed on it.This study includes the feasibility of improving the collapsibility of natural saline soil with 10% salt percent, brought from, Jurf Al-Milih region in Diyala Governorate, by mixing it with randomly distributed nail reinforcement, with three different lengths "Ln", related to width of footing "B" , (Ln/B=11%, 14.2% and 21.4%). By carrying settlement test for single model footing with time, for treated and untreated model using this technique at both dry and wetting conditions, using locally manufactured Laboratory model. This technique reduce the collapsibility of such soil, 27%.The study includes also the effect of mixing....

This study includes the behavior of lateral earth structures constructed on gypseous soil, wherein in some cases, we are forced to construct such heavy structures over such collapsible soil which may cause severe damage to the structures constructed. To recognize such a special case, a locally manufactured laboratory model was designed for this study. The model includes a thick and stiffened inside, rectangular plastic container (800*500*400mm). The soil used was natural gypseous soil with 5%gypsum content as a reference. additional gypsum percentages were mixed with the 5% gypseous soil reaches (25%, 40%, and 60%). The gypseous soil was compacted to 18kN/m3 density and placed at the lower portion of the container. A gravity precast concrete structure was prepared and placed over the collapsible soil. Highly permeable granular soil was placed beside the lateral gravity structure. Dial gauges were fixed at the top and beside the lateral concrete structure to investigate the vertical and horizontal deflection of such structures at dry and upon wetting by water from a special device manufactured locally, to simulate the rainfall of water from the top of the model, as in nature. The vertical and horizontal movements of the concrete wall are totally random, that is due to the uneven settlement of the wall resting on gypseous soil especially after 24 hours of continuous flooding of water because of fluctuation of water between soil particles and high dissolution of gypsum may have happened after this period due to leaching process and cavity formation ...

The engineering problems faces by a civil engineer in building and construction, is almost foundation problems resulting from the properties of the beneath soil. One of the affected problems is the presence of gypseous soil. The presence of gypsum in some regions reaches up to 70%. Gypsum salts are one of the highly dissolved salts in water. The solubility depends on temperature degree, atmospheric pressure, and PH of the dissolved liquid. There are many treatments for such soils, some of them are physical like earth reinforcement, and compaction. The others are chemicals like the addition of lime, asphalt emulsion, oil products…etc(1). The aim of this study is to investigate the ability to improve gypseous soil by reducing the collapsibility during wetting with water, by the addition of Portland cement with different percentages:( 1.5%, 4%, 6%,7.5%, 10%), to gypseous soil with at different densities14 kN/m3 and 11 kN/m3. A laboratory model test consists of a cylindrical plastic container of 250 mm in diameter and 400mm in height. The soil was artificially prepared by mixing natural soil brought from a location near the Civil Engineering Department building in Diyala University and mixed with 70% gypsum. The density of the soil was controlled by placing the required weight inside the container of known volume, to the required height. A rectangular footing 25mm*40mm made from steel was used. The stress was applied from a fixed loading system designed especially for model tests and.......