Biological improvement of sandy soil by microbial induced carbonate precipitation and the affecting factors
Karim
Roshan Bakht
Ph.D. student, Department of Engineering Geology, Faculty of Science, Tarbiat Modares University
author
Mashaallah
Khamehchian
Associate Professor, Department of Engineering Geology, Faculty of Science, Tarbiat Modares University
author
Reza hasan
Sajjedi
. Associate Professor, Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University
author
Mohammadreza
Nikudel
Assistant professor, Department of Engineering Geology, Tarbiat Modares University, nikudelm@modares.ac.ir
author
text
article
2015
per
Microbial-induced calcite precipitation (MICP) is a relatively green and sustainable soil improvement technique. It refers to a chemical reaction network that is managed and controlled within soil through biological activity and whose byproducts alter the engineering properties of soil.To treat soil, first, the microbial population in-situ is augmented by the injection of additional urease positive bacteria and then reagents are added. This paper provides an overview of the factors affecting the MICP in soil. Several factors including nutrients, bacteria type, geometric compatibility of bacteria, bacteria cell concentration, fixation and distribution of bacteria in soil, temperature, reagents concentration, pH, and injection method are introduced. These factors were found to be essential for promoting successful MICP soil treatment. Furthermore, a preliminary laboratory test was carried out to investigate the potential application of the technique in improving the strength and impermeability of a sand specimen and utilized techniques, materials, methods and empirical process during the test are explained. The results showed that as a result of the calcite precipitation, shear wave velocity increased up to 1000m/s and UCS strength increased to about 300Kpa and permeability of soil decreased significantly upon MICP treatment.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
1
12
https://www.jiraeg.ir/article_68355_68af9a14d016ac4d477279612a5c95aa.pdf
Investigation on the mechanism of Saein Strait Landslide (Nir-Sarab Road) in regard to the hydrological and geomorphological conditions
Farhad
Shahidi
MSc. In Engineering geology, TarbiatModares University
author
Gholamreza
Shoaei
Assistant Prof. of enginnering geology, Geology group, Tarbiat Modaress University
author
Mostafa
Mohammadi Vavsari
MSc. In Engineering geology, TarbiatModares
author
text
article
2015
per
Saein Strait landslide took place along Nir-Sarab Road by the southern flank of Sabalan volcano on June 6, 2005, and damaged 350 m of the main road. The main factors which might affect the stability of this particular slope are the thickness and texture of the soil, extensive weathering, gentle slope to cause the accumulation of the material, and finally the regionally affected groundwater level fluctuations. A research was planned based on the field studies, laboratory tests and numerical modeling to identify the main factors affecting the stability of this slope. Landslide profile and engineering geological properties of materials were applied in the numerical models. The effect of rainfall in soil saturation process was simulated for 35 days prior to the failure. Modeling results shows that the infiltrated rainwater (during the 35 days) into the sliding mass cannot percolate more than 7 m and, thus, it must be followed by another triggering factor. The impact of fluctuation in the groundwater level on the stability of the slop was evaluated using limit equilibrium and finite element modeling methods. Previous studies showed that the local conditions of paleogeomorphologyand the existence of a depression might cause the accumulation of volcanic eruptions materials to create sliding mass today. This depression may drain the surface and the groundwater toward the sliding mass from upstream catchment. The materials are highly weathered and groundwater rise due to the exceptional precipitation (rain and snow) during 2004-2005 water year are the main factors bringing the slope to its yield point.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
13
33
https://www.jiraeg.ir/article_68356_cfe135688cc8fa49fef39999ad97494b.pdf
The effects of petrographic characteristics on engineering properties of conglomerates from Famenin region, northeast of Hamadan province
Mohammad Hosein
Gobadi
Prof. of engineering geology, Bouali University
author
Alireza
Taleb beidokhti
Department of Geology, Imam Khomeini International University,Qazvin , Iran
author
Mohammadreza
Nikudel
Assistant professor, Department of Engineering Geology, Tarbiat Modares University, nikudelm@modares.ac.ir
author
text
article
2015
per
A significant portion of the Karaj Formation in Alborz region is made of tuffs. Tuffs are readily used as construction material in various types of structures in Tehran and its neighboring provinces. The current research studies the petrographical characteristics as well the physical and mechanical characteristics of tuff samples collected from the Karaj Formation in the northern parts of Tehran, Alborz, and Qazvin provinces. In order to study the effect of freezing and thawing on the tensile strength, an 80-cycle freezing and thawing test was performed on the samples. The Brazilian tensile strength was evaluated during difference cycles. Subsequent to the freezing and thawing test, during cycles 15, 30, and 60, a slake durability test was attempted for five cycles. Based on the observed data, the long-term durability of tuffs was evaluated using the decay function model. The result yielded from the parameters of decay function model (decay constant and half-time) during the slake durability test were compared to those of descriptive observations during the experiment. The results indicate that the Slake durability indicator cannot be used to evaluate the decay constant and the half-time of the samples being studied. The decay constant and the half-time yielded through the Brazilian tensile test at different cycles of the freezing and thawing experiment indicate that the decay rate of the samples were not uniform throughout samples. It is recommended, here, that the varying rate of decay should be taken into considerations when samples are chosen for specific applications.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
35
50
https://www.jiraeg.ir/article_68357_27d0271dd9138def44cac14ed453c951.pdf
Introducing a new aggregates index (AI) using petrograghical and geomechanical properties (Case study: Hamedan province limestones)
Gholamreza
Khanlari
Professor of Engineering Geology, Department of Geology, Bu-Ali Sina university, Hamedan, Iran
author
Fatemeh
Naseri
Ph.D student of Engineering Geology, Department of Geology, Bu-Ali Sina university, Hamedan, Iran, Khanlari_reza@yahoo.com
author
Ava
Osman Pour
M.Sc. of Engineering Geology, Department of Geology, Bu-Ali Sina university, Hamedan, Iran
author
text
article
2015
per
Aggregates are materials which are used extensively in construction industry such as concrete constructions, road base and subbase and rail ways. Hamedan province has extensive sources of limestones, so it is essential to evaluate the limestone characteristics for their applications in different civil projects. In this study, Hamedan limestones are classified based on their applications in projects with different sensetivites by considering aggregate parametrs (Aggregate impact value, Aggregate crushing value, Los Angeles aggregate abrasion value) and petrography investigations. This classification is called aggregate index (AI). Then, this index is divided to P wave velocity called aggregate adjusted index (AAI). Finally, this parameter has been estimated by simple and multiple (by using bestsubsets) regression methods, based on physical and mechanical properties of studied rocks. In simple regression, Schmit hammer rebound is the only parameter which has a determination coefficient less than 50% and it is not suitable for estimation, while in multiple regression the best parameters (e. g. P wave velocity, uniaxial compressive strength, tensile strength and dry density) have been chosen and unfavorable parameters have been ignored which finally leads to a relaible equation with 99% significant level.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
51
66
https://www.jiraeg.ir/article_68358_38a755d3683701c48d585405dfdf0be8.pdf
Dynamic stability analysis of jointed rock slopes under earthquake condition (Case study: Gas Flare Site of phase 7 in South Pars gas complex- Assalouyeh)
Mohammad
Azarafza
M.Sc. of Engineering geology, Faculty of Sciences. University of Yazd, I.R. Iran
author
Ebrahim
Asghari-Kaljie
Assistant Professor, Faculty of Natural Science. University of Tabriz, I.R. Iran
author
Mohammadreza
Moshrefy-far
Assistant Professor, Faculty of Science. University of Yazd, I.R. Iran
author
text
article
2015
per
Evaluation of rock slope stability during earthquake is the most complex issues in the field of rock mechanics studies. Having understanding of the dynamic forces on rock structures play an important role in stability analysis is jointed rock slopes. In this study, the stability analysis of jointed rock slope, is located in the Gas Flare Site form Phase 7 in South Pars Gas Complex under dynamic load using numerical discrete element method (DEM) by the UDEC software has been estimated. The mass of this slope consist Aghajari formation's marl and sandstones. As dynamic load, the earthquake occurred 2013 at 7 km from the studied site with ML= 3.3 magnitude intended and normalised to PGA 0.42g. Based on the results of the static analysis using hybrid modeling method by MATHEMATICA software, the factor of safety (FS) for this slope is 1.26 determined. For dynamic analysis, the model 6 seconds under dynamic waves with the highest acceleration effect in 0.005 sec steps and 0.5% damping is placed. The results of the dynamic analysis shows, this slope under dynamic loads the safety factor to 0.54 dropped and slope is unstabled. Therefore, to stablizaiton of this slope during strong earthquakes requires to using the stabilization plan.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
67
78
https://www.jiraeg.ir/article_68359_3a0a259ccd0b44f536dbb8364693ad65.pdf
Study of bearing capacity and settlement on jointed rock masses using empirical and numerical methods
Javad
Sharifi
PhD studend of Engineering Geolofy, Ferdowsi University, Mashhad – Iran
author
Mohammad
Ghafoori
Professor of Engineering Geolofy, Ferdowsi University, Mashhad – Iran
author
Saeed
Aredeshiri Lajim
MSc of Soil and Foundation Engineering
author
text
article
2015
per
In order to determine bearing capacity and settlement of foundation on jointed rock masses, first empirical and numerical methods were reviewed, then to obtain the exact properties of a rock masses, a site was selected and parameters were extracted from a real structure. In next stage, in-situ tests were done, and then intact parameters of rock were done in the laboratory. Then engineering classification of rock masses were carried out and parameters of the rock mass were calculated and to determine the bearing capacity and settlement of experimental and numerical methods were used. In due to discontinuous rock structure, UDEC software was used for numerical modeling. The results showed that the experimental methods for bearing capacity suggested a certain range of stress, which requires correction for engineering applications, but further details of the numerical methods; provide surcharge distribution in the foundation. Also results of modeling show that numerical methods for discontinuous rock structures and ground conditions closer to reality and its results are reliable.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
79
90
https://www.jiraeg.ir/article_68360_671c0c7fd0c5f71d05807dcf0e3f2ba6.pdf
The effect of glycerol on compressional strength of soil and soil – cement mixture
Mahdi
Khatibi
MSc Student of Hydro Structures Engineerig, Tehran University, mehdi.khatibi@ut.ac.ir
author
Ali
Reissi Estabragh
Associate Prof. of Irrigation and Reclamation Engineering, Tehran University
author
text
article
2015
per
Glycerol is a hydrocarbon compound and is considered an environmental organic pollutant. This paper presents the effect of different percentages of glycerol on the strength of soil and soil-cement mixtures. Compressive strength experiments were conducted on natural soil and soil-cement (with %3 and %6 cement) samples contaminated with different percentages (%3, %6 and %9) of glycerol. Results indicated that compressive strength of soil samples prepared with different percentages of glycerol decrease compare to natural soil while increasing compressive strength of soil-cement mixtures at low percentages (%3) of glycerol. Furthermore using higher percentages of glycerol (%6 and %9) caused decrease in the compressive strength for soil-cement mixtures
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
91
98
https://www.jiraeg.ir/article_68361_7878f3934b88c418eedc92894714507f.pdf
Upper Red Formation sandstones under Brazilian and point load test conditions
Gholamreza
Khanlari
عضو هیأت علمی گروه زمین شناسی دانشگاه بوعلی سینا
author
Yasin
Abdi lar
دانشجوی دکتری زمین شناسی مهندسی دانشگاه بوعلی سینا
author
text
article
2015
per
This paper deals with the effect of lamination on the failure strength and fracture pattern of Upper Red Formation sandstones in southwest of Qom, Iran using Brazilian and point load tests. For this purpose, six blocks were taken from a part of this formation and have been drilled at different directions of lamination planes such as 0°, 30°, 45°, 60° and 90°.Although, the selected sandstones are seems similar but, the carried out test results and their failure patternsare different. The tensile strength, point load index and failure patterns in different inclination angles were determined for this group of sandstones. Also, the transitional angle of failurehas been determined for Brazilian and point load tests. The test results clearly indicated that failure strength and fractures pattern of laminated sandstones is a function of lamination inclination angle. Also, the results show there is a good correlation between strength and failure pattern of this group of sandstones under Brazilian and point load test conditions.
Scientific Quarterly Journal of Iranian Association of Engineering Geology
Iranian Association of Engineering Geology
2228-5245
8
v.
شماره 1 و 2
no.
2015
99
106
https://www.jiraeg.ir/article_68362_59568a6b52bd48313781f72657775ae7.pdf