ENGINEERING GEOLOGY
Year:2021 | Volume:14 | Issue:1|Papers Count:7

In addition to being a major environmental hazard, hydrocarbon Contamination, in contaminated sandy soils, reduce its resistance parameters and are released as an environmental and engineering hazard to nature. There are many ways to refine and improve such soils. In the present study, improvement of soils contaminated by two types of hydrocarbons (motor oil and gasoline) was performed using the Sporsarcina pasteuri strain bio-based injection method and then calcium carbonate sequestration in a tank based on the gravity penetration of microbial improvers. Effects of Hydrocarbon, Density and Inhibitory Effects on Exposure to Microorganisms (Using Disk Inhibitory Test Results) are among the factors that influence the rate and mode of recovery and improvement with any degree of success in hydrocarbon contaminated soils. Thus, the results of the improvement process were investigated after injection and, obviously, due to the high inhibitory of the motor oil to the gasoline, the improvement process in this pollutant was less than that of the gasoline. Most bio-improvement also occurred in non-polluted soil.

This study was evaluated relationships between uniaxial compressive strength with porosity and characteristics of petrography contains type of cement and quantities of quartz, feldspar and rock fragment on 22 samples of sandstone which collected from formation of Kope Dogh zone. Use of correlation relations among uniaxial compressive strength with petrographic properties can be used in the estimation of compressive strength at a lower cost and less time. For this purpose used Pearson correlation coefficient and univariate and multivariate statistical regression. The results show that the method of petrography introduced to calculate uniaxial compressive strength is a method with low error estimation to find the strength of sandstones studied. These results showed that in sandstones, unlike other rocks the role of the type of cement (silica or calcium) on the strength of these types of rocks is more than the role of the type of constituent minerals and porosity. According to the results a relationship with acceptable accuracy is proposed to predict the uniaxial compressive strength of sandstones based on the percentage and type of cement.

Concrete is the most widely used materials in construction throughout the world. Among its properties, strength is the most important, controlled with utmost care by engineers and designers. Concrete is made of different materials: aggregate, water, cement and admixture. Aggregate occupies approximately 75% of the concrete mass; as a result it definitely has an important role in the properties of fresh and hardened concrete. In this research, in order to study the effect of different aggregates in sulfur and conventional concrete, 7 types of rock have been selected including River material, Granite, 2 types of Limestone, Coquina, Travertine and expanded clay. Having designed the machine, the aggregate was prepared from these rock types; then the physical and mechanical characteristics of the samples were determined. After selecting an appropriate mix design which could be applied to both types of concrete, samples were prepared and investigation showed that weak aggregates which are not used in conventional concrete, can, with changes in the mix design, be used in sulfur concrete and provide the needed strength(Coquina that gained 17. 6 MPa in conventional concrete reach to 43. 6 MPa in sulfur concrete). Furthermore, texture and porosity play an important role in sulfur compared to conventional concrete.

Dams are mainly constructed of earth and rock-fill materials and hence they are generally referred to as embankment dams orfill-type dams. The role of drainage system is also vital as it shifts the phreatic surface ensuring the safety of downstreamtoe. This paper presents the results of seepage analyses of the considered earth dam using finite element method. Slide software is one of geotechnical program that is based on the finite element and canconsider analysis like stress-strain, seepage, slope stability, dynamic analysis and also fast water drop inreservoir. In this research seepage analysis in Roudbar Lorestan dam has been done by Slide software. In orderto evaluate the type and size of mesh size on the total flow rate and total head through the dam cross section, four mesh size such as coarse, medium, fine and unstructured mesh is considered. Result showed that averageflow rate of leakage under the different mesh size for Roudbar Lorestan dam equal 629584 m3 per year for the entire lengthof the dam.

In this paper vibration of cutting machine during sawing carbonate and granite ornamental stones was investigated through making a cutting machine on a laboratory scale. For this purpose, properties 7 samples of carbonate stones and 5 samples of granite stones were measured and 211 sawing experiments were performed. Predictives models were developed using different variation of physical and mechanical parameters by incorporating statistical and intelligent methods. The performance of the developed models was evaluated using R2, RMSE, MAPE and VAF criteria for two different types of test datasets consists of Type A and B; data type A included data for rock samples available at the learning stage and data type B included data for rock samples not available in the training phase. The best model for each group of rocks was introduced by taking ranking strategies, evaluation criteria, speed, easiness and reliability of developing method into account. Results indicated that the best model for both rock type was in the form of multivariate nonlinear regression. The similar parameters of these models were depth of cut, feed rate and Schmiazek abrasivity factor. In addition, Young’ s modulus and UCS were the special parameters in the carbonate and granite rock models, respectively. These special parameters were in accordance with the finding of sensitivity analysis results.

In this paper, the effect of time delay interval on blast-induced weakness has been studied. For this purpose, three similar concrete blocks with dimensions of 50 ×30×14 cm have been constructed and a number of experiments have been designed and performed on these blocks. In each block, three rows with three blastholes in each row have been drilled. The diameter of the blastholes is 6 mm and pacing and burden were designed 75 and 50 mm, respectively, giving an S/B ratio of 1. 5. Twelve points were arranged on the blocks in four lines and three rows to measure ultrasonic wave velocity before and after delay blasting. Blocks were blasted by detonating cord of 12 g/m in three different delay time intervals between rows including 25, 50, and 75 millisecond. Weakness index was defined by incorporating difference of ultrasonic wave velocity in intact and blasted blocks. The results were analysed and discussed for different measuring directions and contour plot of weakness in blocks was plotted. This study concludes that increasing of time delay interval has different effect on the magnitude and distribution of weakness.

Having knowledge about geological and engineering properties of marine sediments, is very important to perform stability analysis of offshore structures. In this paper, the geological engineering characteristics of marine sediments (from seabed to a maximum depth about 30 meters below seabed) was investigated in three oil and gas fields located in the northwestern Persian Gulf. In the first step, geotechnical database of study area was developed based on studies carried out by marine geotechnical labs and oil companies in Persian Gulf. Then, the distribution of physical and mechanical properties of marine sediments with depth and also their relation to the other parameters were studied and some graphs and geological/geotechnical profiles were drawn. The results showed that the physical and mechanical characteristics of these sites are influenced by the distance from the Iranian coast, water depth and distance from Arvand Rud river delta. Generally, from siteI to siteIII, the grains size, and liquid limit of fine-grained and strength of subseafloor sediments were increased. The thickness of soft sediments was decreased from siteI to siteIII. By evaluating the percent of carbonate content, it was found that with distance from the coast, the percent of carbonate content in subseafloor sediments were decreased. So, the least amount of carbonate content was observed in site III. According to the result of PI versus PL/LL graph, Illite is the most abundant clay mineral in the study area.