پژوهشنامه حمل و نقل
سال سیزدهم شماره 2 (پیاپی 47، تابستان 1395)

Soil slopes are structures that apply in many cases such as roads, rail ways and many others. These structures need to be reinforced in the case of low-resistance ground, loading on a slope or geometric properties such as very steep or high slope. One of the methods for analyzing the behavior and providing appropriate model for designing the slopes is the Schmertmann method. In this method ,the influence of reinforcement in the vicinity of sliding surface is considered so that the vertical component of reinforcement force increase the vertical forces on the slip surface ,thus increasing the shear strength .but pulling out the reinforcement during mass movement and interaction between soil and geotextile and the vertical component of resultant shear stress between them can decrease the resistance forces perpendicular to the slip surface and so the safety factor of the slope. In order to verify the accuracy of the problem, this study is performed using ABAQUS software based on the finite element method .seen as a result that interaction between soil and geotextile has little effect on reducing the resisting force and the factor of safety of slope.

Rail transportation¡ as link between demand and supply centers and the maintaining factor for economic and social activities within a country¡ is important from two dimensions: national development and final prices for goods and services and has a key and essential role in almost all economic processes of a country. Therefore¡ a precise and comprehensive attention to each one of the rail transportation infrastructure elements considers being main components of reaching growth and development goals of a country. Iran is no exception¡ in which with 1648195 square km its economic development has been seriously affected by its rail transportation infrastructure development. This paper is aimed to review the effect of rail transportation development of Iranian economic growth in the period of 1972-2010. In order to estimate the model the Vector Autoregressive has been used and for review of rail transport development factors such as the amount of load in tons times km¡ distance in person times km¡ number of passengers¡ and diesel consumption were used. The results from estimating the model show that load in tons distance in person time’s km¡ number of passengers have positive impact and diesel consumption has negative impact on economic growth. The study was done by using E-Views software.

Look at the History of Transportation shows that efficient transport system, an important factor for the preservation and conservation of cities from ancient times to modern age. Technological and economic development of human society, human evolution happened very fast. With skyrocketing demand in the Networks, the traffic is not carried out to meet the transport demand. In such Networks, management solutions in the field of supply and demand, generally using a temporary solution to the problems remain. That is why other methods known as Unconventional method, used. One of these methods is U-turns. U-turn maneuver is one of the most complicated maneuvers which recently welcomed researchers. In this study, the Kermanshah - Biston highway were studied. Data collection was performed in one day with normal weather conditions for 6 hours using video techniques. After Data analyzing, network was modeled in Aimsun micro simulation. Considering the U-turn’s current condition in the study area, five scenarios were designed to find the best way to U-turn maneuver must be matched. Each scenario was simulated 5 times and each time for 1 hour. The simulations’ results revealed that replacing current U-turn with underpass is the best scenario in study area based on measure of effectiveness, so that network’s delays and travel time improved. Considering the data collection, validation on the simulation Model was performed and the results confirmed the accuracy of the model.

Public ground transportation is one of the sectors that has a major impact on economic activity¡ such as increased efficiency in othe sectors and related activities. In this context¡ the knowledge of transportation economy¡ is trying to make the best use of transport facilities to meet the need to provide a definite shift in time and place. The main objective of the study was to analyse the components efficiency of regional rail-passenger transportation in 14 regions of Iran for the years 2007-2009. For this purpose data envelopment analysis (DEA) was used to measure technical¡ managerial and scale efficiency in terms of constant returns to scale production attributable to Charns¡ Cooper¡ Rhodes (CCR) and variable returns to scale in terms of production attributable to Bnker¡ Charns¡ Cooper (BCC).On the basis of results¡ inefficiency levels in rail-passenger transportation section are 0/44¡ 0/42 and 0/38 respectively during 2007-2009. The results showed that the average performance of the estimated components including technical¡ managerial and scale efficiency in rail-passenger transportation were 0/59¡ 0/65 and 0/85 respectively during the period of study. Therefore it is suggested that the rail passenger transport sector should increase its output potential level by 41 percent. The main reason behind the presence of weak performance in the sector could be attributed to old and frustrated rail way infrastructures and limited rail transport navigation system that causes waste of energy in the industry.

The weaknesses of the traditional asphalt cements produced by the refineries are the main factors in premature failure of asphalt pavements. One of the measures to prevent these failures is the modification of the asphalt using additives. A variety of materials have been used for modification¡ among which are polymers and nano materials¡ including nanoclays. As the effects of these two types have not been compared in the literature¡ this paper describes the results of an experimental work¡ in which the effects of a type of nanoclay and Styrene-Butadene-Styrene¡ SBS¡ on the properties of 60/70 penetration grade asphalt cement have been investigated. Different amounts of each additive have been added to the asphalt¡ and the properties of penetration grade¡ softening point¡ penetration index¡ dynamic viscosity¡ and the rheological properties including phase angle and complex dynamic modulus have been studied. The results show that¡ both the additives have a stiffening effect on the asphalt¡ which increase the strength against permanent deformation. However¡ the stiffening effect is dependent on the type of additive and the amount of them used for modification. The SBS polymer has a better effect for improving the resistance against permanent deformation.

Transportation is linkage between production cycles to consumption and remaining production to consumption. The development of this sector is Predisposing economic growth of any country. Statistics also show that the rapid growth of the transport sector advances in technology and high share in economic activities. In this section the services include road¡ rail¡ air¡ rail¡ marine and pipeline that each of these sections are divided into two categories of cargo and passengers. The Combination of any of these services in each country and Utilization of the added value of it depends on the structure of the country. Due to the great impact on energy demand and economic growth Market developments in this market is important.in this study estimates and forecasts for the entire world and 12 regional by 2030 will be discussed. The main methodology used in this study is panel cross section panel data. In this study prediction of the air traffic demand are based on different scenarios by 2030 for the world and the region is 12. Due to the most complete database of domestic and international¡ passenger and freight (both planned and unplanned) air transportation we use International Civil Aviation Organization (ICAO) data.

In this paper¡ study for how favorite use of metro¡ impact in using metro for passengers. Us method for simplification¡ use passengers crowded for case that show level of favorite of the passengers. For quantity this item and finally comparison that by other impacted items use of standing space density of passengers. By using of Multinomial Logit Model¡ and by comparison of two condition : one- condition of crowded passengers in metro and bus¡ two- condition of crowded passengers in metro and no crowded in bus¡ studying for this fact that how many of passengers forgive because of premium of metro and prefer having comfort. And finally¡ as result could get that by changing in condition of crowded passenger¡ will change in mode selection of passengers.