Assessment of Some Geotechnical Properties for Soils of Euphrates River Banks (Kufa- Mishkhab), Middle of Iraq

Twelve stations in the cities of Kufa and Mishkhab were selected for studying the geotechnical, including physical, engineering, chemical and mineralogical, properties of soils in the river banks along the Euphrates River. Grain size distribution of the bank soils showed higher silt than clay and sand percentages. Soil samples from the 12 stations were classified according to the USCS standards. Silt with low plasticity constituted 91% of the silt fraction, whereas that with high plasticity composed 9%. The saturated density values ranged between 1.75-2.073 g/cm3 with an average of 1.953 g/cm3, while the dry density values ranged between 1.307-1.740 g/cm3 with an average of 1.553 g/cm3. The values of the dry and saturated density are within the permissible limits. Direct shear test showed cohesion values (C) that ranged between 15-55 kN/m2 with an average value of 34.8 kN/m2. The values of the internal friction angle (Ø°) of the clay type of soil with low plasticity ranged between 8.5°-17° with an average of 9.91°. The Ø° values of the other soil types ranged between 9°-17° with an average of 25°. Therefore, clay with high plasticity had higher Ø° values than the permissible limits. The results of unconfined compression test showed a range of 22.802-58.587 kN/m2 with an average of 38.173 kN/m2, with water percentage of 30%. The mineralogical tests of the bank soil performed using XRD analysis showed that the analyzed soil samples are composed mainly of quartz, calcite, chlorite, palygorskite, and montmorillonites. The pH value ranged between 6.4-7.55 with an average of 7.10, indicating low basicity. Gypsum concentrations ranged between 0.049-12.75 % with an average of 3.99 %, while that for carbonate ranged between 5-45 % with an average of 26.16%. Sulphates concentration ranged between 0.23-5.93 % with an average of 1.85%. Several treatment measures are proposed to stabilize the soil of the studied area.

Algorithm for 2D Modeling of the Propagation of a Sound Wave in an N-layer Elastic Medium with Inclusions with Various Physical-Mechanical Properties of a Hierarchical Type Located in an Oil Reservoir

<p>A new method has been developed for modeling acoustic monitoring of a layered-block elastic medium with several inclusions of various physical, mechanical and phase hierarchical structures. An iterative process is developed for solving the direct problem for the case of three hierarchical inclusions of l, m, s-th ranks based on the use of 2D integral-differential equations. The degree of hierarchy of inclusions is determined by the values ​​of their ranks, which can be different. Hierarchical inclusions are located in one layer: the first is anomalously dense, the second is anomalously plastic, and the third is anomalously elastic and fluid-saturated density. The degree of filling with inclusions of each rank for all three hierarchical inclusions is different. The simulation results can be used in monitoring studies of the control of fluid return from oil fields developed as part of horizontal drilling.</p><p> </p>

Influence of Engineering Dewatering on Soft Soil’s Density Characteristics

The change of Shanghai soft soil’s density with drainage time during foundation pit dewatering was investigated, through taking samples in each soil layer to be laboratory tested after the groundwater level of observation hole in project site had been lowered below the position soil sampled for at least 5 days. Experimental results show that groundwater included in drainage zone couldn’t be discharged immediately with the drop of groundwater table, which may be named as “lag draining” phenomenon; soil’s water-holding density can also be deduced from soil saturated density and specific field except directly measured from laboratory test. The effect of engineering pumping will reduce the discrete of soil density distribution; a centralized distribution of soil density emerges after dewatering.

The Quantitative Calculation the Volume Fraction of Cement Pastes

The knowledge of the microstructure is a point of major importance to understand the transport, mechanics, creep and shrinkage properties. The present work proposes a method to quantitatively predict the volume percentage of each of phases in Portland cement pastes. The saturated density of C-S-H is revised as a function of degree of hydration and water to cement ratio (w/c). The computed results are consistent with experimental values for cement paste that performed in this study.