The soil liquefaction potential has been evaluated for the Ariana region because of its important socioeconomic interest and its location. Liquefaction susceptibility map is carried out using a decisional flow chart for evaluation of earthquake-induced effects, based on available data such as: paleoliquefaction, geological, groundwater depth, seismotectonic, sedimentary features and Geotechnical parameters in particular laboratory testing like grain size analyses and state parameters. Survey results showed that some of these localities are considered as possible sites to soil liquefaction. Indeed, Quaternary alluvium deposits, paleo beaches and recent deposits that edge the lake and the sebka constitute the most susceptible locations to liquefaction. In the East and the West sides of the studied zone, quaternary deposits are less susceptible to the liquefaction due to the groundwater level deepening and to the relatively old age of the deposits. Elsewhere sedimentary formations are classified as non-liquefiable as they are heavily compacted and old.

Geotechnical earthquake zonation as one of the most important factors necessary for town and country arrangement and also development of different region, is able to provide valuable information on the studied areas. In this study, based on a wide range of geophysical test results in Semnan City, iso-velocity maps of shear wave and iso-depth maps of shear wave velocity were provided using ArcGIS program. Using iso-velocity maps of shear wave, seismic bedrock depth was determined through three different criteria for Semnan City area. Seismic bedrock depth in Semnan City was measured from about 5 to 30 meters according to the Standard 2800. Based on zonation and according to the nature and type of sediments, southeast of Semnan have greatest depth and northeast have the lowest depth of seismic bedrock. The average shear wave velocity varies between 427 and 804 meters per second in the depth up to 30 meters. In general, from the northern to the southern part of the city, the average shear wave velocity decreases and the depth of seismic bedrock increases. Furthermore, soil was classified using the study results and based on the Standard 2800 and European Regulation. The results showed that Semnan City area often falls into group II according to the Standard 2800 and mainly into group B based on the European Regulation.

Penetration Tests are one of important Geotechnical insitu Tests by which, different soil parameters can be estimated. The advantages of these Tests are easiness, high speed, and repeatability. In this research, a penetrometer called as “, Manual Dynamic Penetrometer (MDP)”,is utilized to perform Tests on dry Firoozkuh Sand with three different relative densities. The MDP is similar to other penetrometers used in Geotechnical engineering, but the dimension is different which causes to generate more power to penetrate into the soil with deeper layers. The aim of this research is to investigate the effect of cone geometry as well as applied energy on test results. To do so, three different cone diameters and cone apex are considered. In addition, the mass of the hammer is also changed in three different values. The comparison of results indicate that the come apex does not influence the penetration value,however, the cone diameter plays the role. It is also seen that the applied energy has direct relationship with the penetration. Since the mechanism of the cone penetration is similar to that of pile driving, it was also shown that it is possible to estimate the residual internal friction angle of the soil by using empirical formula proposed by Meyerhof.

Facilities built in areas affected by earthquake activity, such as tunnels, which have always been an integral part of human life, must withstand both dynamic and static loading. It has led to the need for practical studies on the effects of earthquakes on underground structures and the factors affecting their destruction. For this purpose, in this research, at first different patterns of tunnel’s excavation were investigated and by using Plaxis 2D software and based on Tabas earthquake in Iran, sensitivity analysis on Geotechnical parameters of the soil surrounding tunnel such as cohesion, friction angle, unit weight and modulus of elasticity was carried out, and the parameters whose changes have the greatest and least effects on the bending moment changes on the tunnel lining are introduced. The results show that tunnel excavation patterns significantly affect the bending moment, axial forces, displacements, and surface settlement of the tunnel. Often, by dividing tunnel excavation area to small parts, the values of bending moment, axial forces, displacements, and surface settlement of the tunnel decreases in static analysis. Also, outputs of sensitivity analysis on Geotechnical parameters of the soil surrounding tunnel showed that modulus of elasticity of the soil surrounding tunnel has the most effect and cohesion changes have the least effect on bending moment induced on tunnel lining..

Introduction: Geotechnical investigations merely through boring and engineering experiments are considered a difficult task as they are highly costly and time-consuming. The identification of large areas initially requires geological studies followed by the inclusion of Geotechnical information. Finally, a geological and Geotechnical classification is prepared for the entire area. This type of classifications is employed in strategic urban planning and quick selection of Geotechnical variables in small-scale projects. The present research performed the steps involved in these investigations and classifications for the city of Sanandaj, Iran. Hence, the geological-Geotechnical classification of the city of Sanandaj was presented by integrating the geological information of this city with the Geotechnical data obtained from drilled boreholes as well as multiple wells at different locations in this city. . . . . .

Results of laboratory Tests on specimens produced from subsoil studies were evaluated to characterize Geotechnical properties of Tabriz Marl. It was concluded that, Tabriz Marl may be considered as a high liquid limit silt or clay (MH & CH). Range of changes of index, physical and mechanical properties of the Tabriz Marl are comparatively vast. Correlation between these properties has been introduced in this paper. A representative specimen was tested for swell potential after compaction and also for thermal and lime treatment effects. Swell percent and pressure as high as 13.6 % and 1020 kPa were measured and need for treatment was proved. It was shown that with thermal treatment substantial modification only starts as the temperature rises beyond 300° C. At 500° C the plasticity index and also the swell percent decrease to less than 5.0 % and 1.0 %, respectively. With lime treatment, plasticity index decreases as the lime content is increased until the lime fixation point is achieved at about 3 % lime content, beyond which, modification effects are not considerable. Addition of just 1.0 % lime to the soil decreased the swell potential to 5.0 %. Further results, merits and shortcomings of both treatment methods are introduced during the text.

Geotechnical engineers often encounter complicated multivariate problems that involve a number of interacting factors. Commonly, the relationship between these factors is not precisely known. In addition, the data associated with these parameters are usually incomplete or erroneous (noisy). The extraction of knowledge from the data in order to develop a relationship between these factors is a formidable task requiring sophisticated modeling techniques as well as human intuition and experience. This paper demonstrates the use of neural networks to alleviate this problem. Neural networks have emerged as a powerful computational technique for modeling nonlinear multivariate relationships. This paper provides a brief overview of the basic architecture and concepts of neural networks. followed by a review of current applications of neural networks in Geotechnical engineering and a discussion of some potential applications.