JOURNAL OF ENGINEERING GEOLOGY
Year:2013 | Volume:7 | Issue:1|Papers Count:7

The study area is located in Jiroft district, Iran, and is a part of Sahand-Bazman volcanic zone. Various landslide factors and importance of each identified qualitatively, based on previous studies and regional specifications. Three landslides were recognized in the study area using direct method (field work) and aerial photographs interpretation. One of these landslides is located in the vicinity of Mohammad Abad of Maskoon Village. The aim of this study is landslide hazard mapping using two integration methods that includes Fuzzy logic and Hybrid Fuzzy-Weight of Evidence (Hybrid F-W of E). Resulted maps from both methods, show a good agreement especially in introduction of high hazard regions. The hybrid method is based on the occurred landslide points and is more scrupulous, so hazard regions delineated by this method occupy smaller areas than the areas introduced by fuzzy model. Therefore, hazard maps resulted from Hybrid and Fuzzy methods, can be considered as minimum and maximum limits of landslide hazard in the area, respectively.

Evaluation of ground response is one of the most important issues is considered in seismic geotechnical. Alongside the earthquake path associated to region soil, generally earth movement in places with soft soil is greater than the movement in places with harder soil. This project seeks to identify local soil condition of ARDAKAN which influences on earthquake wave shake. Therefore after digging of boreholes and doing geotechnical and Down hole geophysical tests, soil layer and their thickness have been determine. Then shear wave velocity and layers density determined. With using these data we developed shake geotechnical models for deferent city regions. Finally earth’s powerful movement parameters have been determined by utilizing density, wave velocity and with using EERA program to equivalent- liner method. This work was repaid for return period of 75, 475 and 2475 year. It is fund that northwest region of city has most amplification.

In this research, one of the new methods for seismic landslides hazard zonation (CAMEL) to predict the behavior of these types of landslides have been discussed. It is also tried to eveluate this method with the proposed Mahdavifar method. For achieving this result, the influence of Sarein earthquake (1997), have been selected as a case study. In order to apply seismic hazard zonation, the methodology of Computing with Words (CW), an approach using fuzzy logic systems in which words are used in place of numbers for computing and reasoning is employed. First, the required information which includes disturbance distance, ground strength class, moisture content, shake intensity, slope angle, slope height, soil depth, terrain roughness, and vegetation have been collected using air photos, Landsat Satellite images, geological and topographic maps, and site investigation of the studied region. The data is digitized and weighted using Geological Information System (GIS). At the next step, the hazard rate and areal concentrations with respect to landslide types are calculated using CAMEL program and then, landslides hazard map produced by the above mentioned method is compared with landslides occurred as a result of Sarein earthquake. Finally, for evaluating on prediction of the earthquake-induced landslides, empirical comparison have been done between CAMEL and Mahdavifar methods.

In this study using finite element procedure was used to simulate the dynamic behavior of reinforced soil walls, to evaluate their dynamic response on all types of deformation modes, different mechanisms of failure detection and identification of parameters in each of the modes and the mechanisms. Detailed numerical modeling, behavioral models and materials were described and Dynamic response of the physical model has been validated experimentally. Parametric study has been of the wall height of 5 meters by the effective parameters such as hardness, length to height ratio, the vertical reinforcement, wall height, and acceleration inputs. Three modes of deformation were observed. The study showed that occur bulging deformation mode while the use of flexible reinforcement and occur overturning deformation mode while the use of stiffness reinforcement. Stiffness reinforcements have the most effective in changing the type of deformation. Length to height ratio of reinforcements has the minimum effective in changing the type of deformation.

Wave velocity and attenuation are among the most important attributes of stress waves that propagate through geomaterials. Utilizing these attributes, it is possible to acquire useful information about porous geomaterials such as soil and rock and also the fluids that saturate the pores of geomaterials. The key point in order to gain these informations is to establish an accurate link between field measurements of wave attributes and physical properties of geomaterials’ skeleton and pore fluid. The pore fluids and their inhomogeneous distribution fluid are among factors that affect wave velocity and attenuation to a considerable extent. Patchy saturation of pores which occurs on the scale larger than grians size but smaller than wavelength is one of the reasons that causes inhomogeneity in pore fluid distirbution. The influence of such inhomogeneity is studied in present paper. Two different attenuation mechanisms including relative movement of fluid with respect to solid phase and also attenuation caused by grain to grain contact are implemented to fully assess wave attenuation. It is observed that the former attenuation is more dominant at higher frequencies compared to the latter attenuation.

In this article at first Beheshtabad water transmission tunnel is introduced and mechanized and D&B excavation challenges in squeezing grounds are explored, and the appropriate approaches to reduce the required thrust are presented. then the thrust evaluation methods are considered and the required axial force to penetration in the face according to advance rate, geometry of cutter head and compressive and tension strength of rock is calculated.on the next step, Geo mechanical rock mass parameters in 19th chainage are determined, and the numerical method scheme which is applied to thrust determination is discussed and its results are considered. In following, the required thrust to overcome shield skin frictional resistance using Romani's method is calculated and the obtained results are compared to numerical ones. For application of double shield TBMs in 29030-31600 and 34900-37490 km of tunnel for the most favorable geotechnical parameters three cm and for the least favorable geotechnical parameters ten cm over cutting is essential. In 31600-34900 km utilizing double and single shield TBMs aren't possible and to decide on the usage of double and single shield TBMs a exploration gallery should be planned and executing additional tests to determination of long term parameters of host rock is required.

Various types of numerical analyses such as the Finite Element Method, the Boundary Element Method and the Distinct Element Method, are used in rock mechanics and in engineering practices for designing rock structures such as tunnels, under ground caverns, slopes, dam foundations and so on. In this paper, the results of back analysis of Koohin tunnel which is located in the first section of Qazvin – Rasht railway have been presented. The main purpose of this paper is to perform the back analysis of the mentioned tunnel with the use of numerical models. For modeling the tunnel, two different sections are analyzed with Flac 2-D software, which are 30+150 and 30+900. To perform back analysis the suitable interval of geomechanical parameters according to the tests which performed on the core drillings has been determined. With the use of Direct Method in back analysis, the errors of models have been corrected in several steps and finally the geomechanical parameters of control in 30+150 station (Elastic Modules = 0.3 GPa, Cohesion = 0.21 MPa & Internal Angle of Friction = 34o) and in 30+900 station (Elastic Modules = 0.3 GPa, Cohesion = 0.21 MPa & Internal Angle of Friction = 35o) have been achieved. The geomechanical parameters which achieved from back analysis are completely in the chosen interval and compliance with the results of tests which performed on core drillings. On this basis and according to the match of the geomechanical parameters which obtained from back analysis with the parameters which used in designing of the tunnel, the tunnel design and the structure method were confirmed.