Quaternary Journal of Iran

Abstract Aggregates' resistance to degradation caused by the crystallization of sodium sulfate mainly depends on their lithology. Nonetheless, aggregates' accumulation environments can also affect their weight loss induced by crystallization of sodium sulfate. The present study sought to examine weight loss among aggregates in rivers and colluvial areas. To this end, volcanic and sedimentary rocks were collected from Damavand and Direh, respectively. Lithological features have a profound impact on aggregates' resistance to degradation caused by sodium sulfate crystallization. Therefore, care was exercised to select river and colluvial areas with similar lithology or formation. 
2-Materials and methods
In line with ASTM D2216-1990, ASTM D2216-10, 1990, 10, and ASTM C 88-99a, the collected samples underwent tests of porosity, water absorption percentage, and weight loss due to soundness. In the sulfate soundness test, the samples were saturated and dried in 5 cycles, followed by measuring their weight loss with a particular sieve. In this standard, the chosen sieves do not follow a specific pattern, and a single sieve may be used to gauge weight loss of aggregates with various sizes. In this way, it is difficult to compare the degree of degradation among aggregates with different sizes. Thus, in order to measure weight loss, the lower limit sieve was used for each range of aggregate sizes.
In addition, the microcrack percentage of the collected samples was investigated. To study cracks in aggregates, samples with three different sizes (25-37.5, 19-25, and 12.5-16) were collected from rivers and colluvial areas. In total, 150 samples (50 for each aggregate size) were collected from Direh, while 300 samples were gathered from Damavand. For sampling, the aggregates were sieved and divided into four equal parts. Subsequently, one part was randomly selected for analysis (ASTM C 702-98, 2003). Cracks in aggregates, which were studied through naked eyes, were calculated based on the ratio of aggregates with cracks to the total number of aggregates.
3-Results and discussion
The results indicated that the degree of porosity, water absorption percentage, and microcrack percentage are higher in colluvial fans in comparison with rivers. This can be attributed to different lithological processes that dominate the two areas. In rivers, particles travel through long distances; hence, they are more likely to collide with each other and break down along the microcracks. This process results in a smaller number of cracks in aggregates from rivers. Moreover, the weathered areas at the surface of aggregates are removed through abrasion, hence their lower porosity and water absorption percentage. Conversely, in colluvial fans, particles mainly slide in large masses due to gravity. Since aggregates in colluvial fans do not travel through long distances and are exposed to less abrasion, they have a smaller degree of porosity, water absorption percentage, and microcrack percentage. The results of soundness test also revealed that aggregates in rivers experience smaller weight loss compared to the ones in colluvial areas. Aggregates’ weight loss is a function of their size. In river beds, like Direh, the degree of weight loss for aggregates that are 25-37.5 mm is only 5% as much as that of aggregates in colluvial areas. For the smallest size of aggregates (300-600 micron), the degree of weight loss for river aggregates is 38% as much as that for colluvial aggregates. The same situation holds true for aggregates from Damavand, though with smaller difference in the weight loss of river and colluvial aggregates. That is, the degrees of weight loss among big and small aggregates from rivers respectively are 21% and 65% as much as those of colluvial aggregates.
In rivers, a smaller weight loss is observed among bigger aggregates. In contrast, a direct relationship is detected between size and weight loss among aggregates from colluvial areas. Due to the small number of cracks in river aggregates, microcracks play an insignificant role in degradation caused by sodium sulfate crystallization. The surface to volume ratio is greater in small aggregates (in comparison with big aggregates), hence degradation caused by sodium sulfate crystallization takes place at a larger surface of aggregates. Thus, given the smaller surface to volume ratio, bigger aggregates experience less degradation. Colluvial aggregates have a larger number of microcracks, which constitute the main factor in degradation caused by sodium sulfate crystallization. The number of microcracks and the degree of degradation go up in bigger aggregates. In such aggregates, the effect of surface to volume ratio is much smaller than that of microcracks.
There is a significant difference in the weight loss of big aggregates from Damavand and Direh. In colluvial areas of Direh, weight loss increases by around 100% among bigger aggregates, while the same index for colluvial aggregates from Damavand is around 20%. This can be attributed to the smaller microcrack percentage of aggregates in Damavand.
4- Conclusion
The degree of porosity, water absorption percentage, and microcrack percentage are lower in river environments in comparison with colluvial ones, that can be attributed to the longer transportation and hence abrasion of sediments. The rate of weight loss due to soundness is lower in aggregates obtained from rivers compared to those obtained from colluvial environments. In river beds of Direh, the degree of weight loss for large aggregates (25-37.5 mm) is only 5% as much as that of aggregates in colluvial areas, whereas for small aggregates (300-600 micron), the degree of weight loss for river aggregates is 38% as much as that for colluvial aggregates. The same situation exists for aggregates of Damavand, but the difference is lower due to the lower microcrack percentage, so that degrees of weight loss among large and small aggregates from rivers are respectively 21% and 65% as much as those of colluvial aggregates

Abstract Regarding to the importance of the industrial region in engineering project execution, assessment of Geotechnical characteristics is essential to prevent undesired problems. Because of the uprising number of oil and gas industry structures, the Mahshahar Special Industrial Region is very important. So, the Geotechnical investigation in this region is necessary. Executing these investigations guaranties the implementation of any construction projects and prevents any unwanted detrimental events.
The study area is located in Mahshahar Port near in southwest of Iran. This port is one of the important industrial ports of Iran. Mahshahr port is located in area between 49º04´-49º06´E and 30º25´-30º31´N.
Materials and Methods
Based on Sedimentary-structural division of Iran, this area is located in Zagros zone. This zone is limited to Sanandaj-Sirjan zone from the northeast, to the Makran Zone from the southeast, to the highlands of northeastern Iraq and southeast Turkey from the northwest and to Arabian Plate from the south and southwest. Based on geological data, the properties of Zagros zone varies in different areas and this zone is divided to some subzones that Abadan Subzone, in which the study area has located. This subzone is located in the southwestern part of Zagros.
To investigate the Geotechnical characteristics of Quaternary sediments in the study area, eight boreholes data, performed by continuous coring method, with depth 11 to 25m were studied. The seismic downhole test and Standard Penetration Test (SPT) were done in all boreholes. The laboratory tests are included the index tests on soil samples (particle size distribution, Hydrometer, Atterberg test), consolidation, direct shear, uniaxial and triaxial tests. Strata were classified using index tests.
To reveal the stratification of site, the Seismic Downhole test was performed in all boreholes, in which the source was in surface (blow on a plate placed in 2-3m distance from borehole) and the P-wave was measured in geophones installed in different depth of boreholes (1m intervals), so whole depths of borehole were investigated. To measure the S-waves, the blows were stroked in a horizontal direction on timber to generate S-waves. Finally, the relationship between elasticity modulus in downhole and SPT tests and also the relationship between friction angles in triaxial tests with N_SPT values were assessed.
Results and Discussion
The plasticity of soil has investigated using Atterberg test results, performed applying standard ASTM D4318 on all samples. The results show that the Liquid Limit and plasticity index vary between 25-40% and 10-20%, respectively, showing the low to medium plastic characteristic of soil.
The elastic modulus and also the relationship between the elastic modulus on downhole and N_SPT tests were investigated in the study area. Based on the results, the elastic modulus of quaternary sediments of Mahshahar varies between 100-350 Mpa. In general the relative density and the seismic wave velocity of soil strata were increased with depth in this area.
Also, the fitting curve of N_SPT values and elastic modulus in downhole tests show the R²=0.80, in which the N_SPT values were corrected to N₆₀.
Soil classification of the site, regarding the average S-wave velocity of soil up to 30m depth, was performed based on the Iranian Building Code (IBC) 2800. The recorded mean S-wave velocity in all boreholes is less than 375m/Sec so the ground type III (based on IBC 2800) is recommended to be taken into account in the design.
Estimating of friction angle of soils, some researchers like Hunt (1984) have been published some reference tables. In this study, to have a simple equation to estimate the friction angle of quaternary sediments, the results of NSPT and consolidated undrained triaxial test (CU) have been used. The result shows the R²=0.85 for fitting curve. Regarding the results, it can be concluded that because of overestimating of friction angles, the presented tables by Hunt (1984) is not applicable to Mahshahr quaternary sediments. It seems that the main reason comes from remarkable existence Clay soils in the sediments.
Conclusion
In this research, based on data from boreholes, the general characteristics of quaternary sediments were revealed and also the strata were classified based on the Unified System as ML, CL and SM. To determine the elastic modulus of soil, the results of the seismic downhole test were used. Based on these results the elasticity of soil varies from 100 to 350MPa. The relationship between mentioned above elasticity and NSPT was assessed and an equation was determined. In general the relative density and seismic velocity increase with depth in this site. S-wave velocity in Seismic downhole test results were used to determine the site or ground type. This parameter was less than 375 m/Sec in all boreholes. So, the ground type III (IBC2800) is recommended for the whole site. Finally, an equation was concluded for relationship between N_SPT and UC triaxial friction angle which can be more useful than other published relationships (like those by Hatanaka & Uchida) and Hunt’s tables, because these published ones overestimate the friction angle; the main reason of this case is the existence of the great amount of Clay in soil in this site. 

Abstract Introduction
Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid loading. This phenomenon is the result remolds sand particles. Soil liquefaction occurs in loose, saturated cohesionless soil units (sands and silts) and sensitive clays when a sudden loss of strength and loss of stiffness is experienced. Sometimes it is resulting of large, permanent displacements of the ground. Even thin lenses of loose saturated silts and sands may cause an overlying sloping soil mass to slide laterally along the Liquefied layer during earthquakes. Liquefaction and related phenomena have been responsible for tremendous amounts of damage in historical earthquakes around the world. Destruction of buildings, roads, land subsidence, and even loss of life is one of the dangers of liquefaction.
Materials and Methods
Liquefaction hazard evaluations generally deal with three issues: liquefaction susceptibility, initiation of liquefaction, and effects of liquefaction. The issues are generally addressed in the order listed, since the latter issues are dependent on the former. Assuming a soil is judged to be susceptible to liquefaction. Its potential for initiation under the anticipated earthquake loading conditions is then judged. This process is usually described as an evaluation of the soil’s liquefaction potential. There are various methods to evaluate the liquefaction potential of the soils. Using the Soil Penetration Test results is the one of the important method to investigate of the liquefaction potential in uncemented deposits. Seed and Idriss are the pioneers of the using SPT to investigation of liquefaction potential (Seed & Idriss, 1971). In recent decades, evaluation of the liquefaction potential by shear wave velocity has also been recommended by National Institute of Standards and Technology (NIST, 1998). Cone penetration test (CPT) results have also been used to evaluation of soil liquefaction potential by Robertson and Wride (1998).
Results and Discussion
In this research, the liquefaction potential of the Imam Khomeini Port has been investigated. The  port is situated at South-West of Iran at the North of Persian Gulf. In recent decades, numerous numbers of infrastructures and oil & gas facilities have been developed in this area. According to geological investigation the studied area is in the folded Zagros structural zone. No volcanic activities have been reported since Mesozoic. The sedimentary rocks are the main geological formation in this region. The large part of the port has been constructed on low level quaternary deposits without any rock outcrops in the studied area. The quaternary deposits are mainly loose and uncemented. The ground water level of the region normally is high due to penetration of the saline water from Persian Gulf. Considering to high level of groundwater table at sea coastline, the site could be vulnerable to liquefaction during possible earthquakes. It should be mentioned, Zagros folded zone is one the most active part of the Iranian structural zones.
Conclusion
In this study, Standard Penetration Test (SPT) and shear wave velocity (Vs) measurements have been used to evaluate the liquefaction potential of the alluvial. Simplified procedure of Seed and Idriss (1971) has been used to evaluate the liquefaction potential based on SPT method. The cyclic stress ration (CSR) and the cyclic resistance ratio (CRR) were evaluated in 160 borehole data and the safety factor was given in each borehole. The correction factors for depth and cementation of the soils have been applied based on Seed & Idriss (1982) and EPA (1995). The site area is evaluated high liquefaction potential based on this analysis. On the other hand, the liquefaction potential assessed using the Vs measurements based on the method proposed by National Institute of Standards and Technology (NIST) in 1998. In this study, 160 borehole data were studied considering the soil type and ground water level. The safety factor at different depths and liquefaction Potential Index at different boreholes were compared. Generally, results of the two methods are in agreement, especially in shallow depth for SPT method and in lower deep for shear wave velocity method. Based on the analysis results and considering to seismicity of the region, the liquefaction potential is high in some part of the studied area. The result of liquefaction potential evaluation of the studied site has been presented based on different peak ground acceleration. The results showing the most of area are highly vulnerable to liquefaction even by 0.3 PGA. Therefore, we recommend the soil of the area should be treated before any construction in the site. Since the thickness of the loose deposits considerably is high, dynamic soil treatment method specially suggested.