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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Structural Engineering and Geotechnics
- نوع مقاله: Journal Article
- کلمات کلیدی: Liquefaction,Fines content,Liquefaction Potential Index,Overburden,Tabriz Metro Line 2
- چکیده:
- چکیده انگلیسی: As one of the significant phenomena in earthquake geotechnical engineering, liquefaction can cause severe damages. A number of factors play a role in the occurrence of liquefaction such as magnitude of earthquake, void ratio, relative density, and fines content percentage. The impact of building construction overburdens on liquefaction is of paramount importance. The present study was aimed at evaluating the effects of overburden resulting from building construction on liquefaction potential of saturating soil layers along Tabriz Metro Line 2. Fifty-four boreholes and geotechnical information were collected from the research site. Overburden values were considered to be 100 kPa, 200 kPa, 300 KPa, and 400 KPa equivalents to 5-, 10-, 15-, and 30-story building, respectively. The assessment of liquefaction potential of soil layers was carried out using the standard penetration test (SPT) method. Furthermore, liquefaction potential index (LPI) of soil layers was evaluated. The findings demonstrated that overburden can affect liquefaction resistance of soil layers. With increasing overburden, safety factor against liquefaction became less than one in nearly 80% of soil layers. The rate of growth in LPI of boreholes in the research site was found to be roughly 70%. Hence, an increase in overburden elevated liquefaction hazards in the research site.
- انتشار مقاله: 22-02-1396
- نویسندگان: Reza Sallakh Niknejad Sallakh Niknejad,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Structural Engineering and Geotechnics
- نوع مقاله: Journal Article
- کلمات کلیدی: Permeability,Cohesion,Clayey soil,GFRP,Angle of internal friction
- چکیده:
- چکیده انگلیسی: Soil reinforcement can be considered as the combination of two parts. One part is soil for compressive stress capacity and another part is some material such as geosynthetics such as steel belts and fibers for tensile stress capacity. Soil improvement is one of the useful methods to increase the strength parameters of the soil. The main goal of this study is to evaluate the effects of GFRP on the bearing capacity, shear strength, and permeability of clayey soil. For this purpose, the length of GFRP is selected 10 mm and amount of GFRP are 0.2, 0.4, 0.6, 0.8 and 1% that mixed randomly with clay. Mixture specimens prepared using the optimum water content. Bearing capacity of specimens measured by unconfined compressive test and direct shear test. Also, Permeability parameter assessed based on the falling head permeability test. Results of this study showed that with mixing GFRP up to 0.8% increases the clay bearing capacity and flexibility. Although with continuing to add GFRP the bearing capacity decrease, the clay permeability using GFRP is increased.
- انتشار مقاله: 10-01-1396
- نویسندگان: Fardin Asadollahi,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Structural Engineering and Geotechnics
- نوع مقاله: Journal Article
- کلمات کلیدی: Geotextile,Traffic,Soil Improvement,static loading,pavement design,dynamic loading
- چکیده:
- چکیده انگلیسی: One of the methods for the improvement of soil against the tensile stresses is using the artificial supplements in soil such as metal belts or nets, polymer materials and natural fibers. Technically this method is called the reinforced of soil. When a pavement is located on soft soil, great deformations can occur as a result of the crossing of traffic load in superstructure layers of the body. This can finally lead to the increase in the cost of maintenance and traffic pause in transportation. The main purpose of this study is to explore the effect of geotextile layers place in various depths of the body of pavement layers located on soft soil. For this purpose, models with the identical geometry from the transection of road using Finite Element Method software, PLAXIS were analyzed in two dimensions in which the location and the number of geotextile layers were considered in various depths. In continue, these models have been under static and dynamic loadings due to vehicles and the settlement rate and the lateral deformation of pavement in section has been evaluated. The results show that in static loading, the maximum safety factor of stability is that of layers in which the geotextile exists in the partition between subgrade and embankment layers. Also, between dynamic loading and increasing number of geotextile layers favorable result is not achieved. Although more studies need to be carried out in this area.
- انتشار مقاله: 14-09-1394
- نویسندگان: Reza Nazari,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Rehabilitation in Civil Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: improvement,geotechnical properties,clay,Dune sand,Geofoam
- چکیده:
- چکیده انگلیسی: Nowadays, new materials are widely used for improving the bearing capacity of the soils and geosynthetics include the type of these materials which are utilized in this regard. In addition, the geofoam panel type of geosyntethic materials is useful and an alternative for backfill in retaining wall or pavement layers. The present research mainly aimed to investigate sthe effects of geofoam particles (0.2, 0.5, & 1%) on improving the bearing capacity of the clay-sand mixture. To this end, dune sandy soil (passed from sieve No.30 and residue on sieve No.50) was provided from Shore of the Lake Urmia and mixed with kaoline industrial clay at 15, 30, and 50 percentages. Then, compaction, uniaxial in three loading speed (0.5, 1, & 1.5 mm/min), direct shear (in vertical stresses 1, 2, & 3 kg/cm2), and falling head permeability tests were performed to evaluate the influence of geofoam particles on geotechnical properties of the mixed soil. The results showed that maximum dry density and elastic modulus increased by a 0.5% increase in the geofoam in the soil mixture. Meanwhile, the shear strength of the specimens increased as well. Finally, permeability and the drainage condition improved by adding geofoam to the specimens.
- انتشار مقاله: 05-06-1397
- نویسندگان: Behzad Peymanian,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Nano Dimension
- نوع مقاله: Journal Article
- کلمات کلیدی: Shear strength,Sand,viscosity,Silt,Colloidal Nano Silica,injection
- چکیده:
- چکیده انگلیسی: Passive method is a new procedure in stabilizing loose soils. This methodology is a type of interlocking soil particles structures. In order to optimum improve in this method, it is necessary to achieve proper penetration length and increase the shear strength of parameters. Researches have shown an increased resistance to liquefaction and decreased permeability due to colloidal Nano silica injection in soil. In this research, sandy soil was mixed with silt in 5%, 10%, and 15% percent. Then, specimens in dry and saturated conditions were placed under the influence of Nano silica colloid. For determining geotechnical properties of improved specimens, direct shear test was performed in three situations (dry, saturated, and injected). Moreover, for studying drainage condition after stabilizing specimens, constant head, permeability test was carried out. The results showed that geotechnical properties in the injected state increased compared to the non-injected state. Generally, these increase in cohesion and integral friction respectively on average in specimen’s equal 2%, 1.18% and in saturate state equal 1.21%, 1.13%. Besides, with the injection of Nano silica colloid, the amount of vertical settlement in the samples on average 22% decreased. Furthermore, the amount of permeability of the stabilized materials showed on average 58% went down.
- انتشار مقاله: 10-11-1396
- نویسندگان: Ali Kakavand,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: Advance Researches in Civil Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Liquefaction,hazards,South East of Khoy,Liquefaction potential index (LPI)
- چکیده:
- چکیده انگلیسی: One of the important problems in earthquake geotechnical engineering is liquefaction phenomenon that happens in loose saturated granular soils. This phenomenon can cause great damages to underground structures and buildings and lifelines. Liquefaction resistance of soils can be evaluated by experimental and field tests. In this research, results of liquefaction potential evaluation based on standard penetration test (SPT) were proposed. Case study area is Southeast of Khoy city at West Azerbaijan province in Iran. In this study 18 boreholes was collected. With considering type of soils and ground-water table level liquefaction potential evaluated. Then, liquefaction potential index (LPI) assessed. Obtained results showed that almost more of 50% alluvium sediments deposits is included sand and silty sand. Also, liquefaction potential hazard with considering ground water table level is high.
- انتشار مقاله: 21-06-1398
- نویسندگان: Mehrdad Bagheri,Rouzbeh Dabiri
- مشاهده
- جایگاه : پژوهشی
- مجله: Advance Researches in Civil Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Soil collapsibility,Quantitative methods,Qualitative methods,Hir city,Ardebil
- چکیده:
- چکیده انگلیسی: Collapsible soils is one of the problematic soil because of complex mechanism collapse in them, the recognizing and analyzing effective parameters on phenomenon is so important. Collapsible soil is non- saturate soil, due to moisten and specifically loading, connection between soil particles become loose and finally suddenly destroying happen in soil layer. In this study, collapsible potential in soil layers of Hir city based on practical methods were evaluated. 16 specimens were collected in study area. Practical methods were divided to qualitative and quantitative criterions. In quantitative procedure, double odeometer test based on ASTM were performed. Results of this study showed that between qualitative methods there is not good agreement. Although, quantitative procedure proposed high risk in terms of collapsibility in soil layer.
- انتشار مقاله: 24-05-1397
- نویسندگان: Mahnam Roohi Hir,Michael Yousefadeh,Rouzbeh Dabiri
- مشاهده