Journal of Engineering Geology

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The study area is located in Jiroft district, Iran, and is a part of Sahand-Bazman volcanic zone. There are various landslide factors and the importance of each factor are 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). The obtained results of maps from both methods, show a good agreement especially in introducing  high hazard regions. The hybrid method is based on the occurred landslide points and is more rigorous, 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. 

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One of the major challenges in tunneling is the excavation in regions with high potential of squeezing and in the case of application of full face boring machines evaluation of the required thrust in these regions is inevitable. The Beheshtabad water conveyance tunnel with 65 km in length is considered for transferring one billion cubic meter of water annually to the central part of Iran.  According to geological investigation there is a high potential of squeezing in the 19^th section of tunnel. In this article, the thrust evaluation methods are investigated and the required penetration force is calculated. Then the numerical procedure applicable to thrust evaluation in the 19^th section is discussed and the results are analyzed.  In addition, the required thrust to overcome shield skin frictional resistance using Ramoni's method (2010) is computed and the outputs are compared to numerical ones. As a result of numerical simulation, in order to utilize double shield TBM for the sections of 29030-31600 km and 34900-37490 km, it is required to overcut 3 cm for the favorable geomechanical locations and 10 cm for the unfavorable geomechanical conditions. Decision on the application of full face boring machines in the section of 31600-34900 km could be made providing long term parameters of host rock were determined via performing additional in situ tests in the exploration gallery.  

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The Sabzkouh water conveyance tunnel, with a length of approximately 11 Km to transferred 90 million cubic meters of water per year from the Sabzkouh area to Choghakhor Dam, about 80 Km south of Shahrekord in Chahar Mahal-e Bakhtiari province is under study. Because of the long length of this tunnel and also low rate excavation by traditional tunneling methods, the Tunnel Boring Machine has been a priority. Due to limitations of TBMs in complex and unfavorable geological conditions, based on the  precise study performed, the machine was selected. The geological features and the geomechanical properties of rock masses play an important role to selection of proper TBM. In this paper, by estimation of the most important geomechanical properties and geological conditions of the rock masses, with the interpretations of geotechnical logs and the laboratory test results combined with field observations, the rock mass of the Sabzkouh tunnel, based on the three common engineering systems of RMR, Q and GSI was classified. According to classification systems, the rock masses are divided into three geotechnical zones. Based on the uniaxial strength of intact rock, the properties of discontinuities, fault thickness and shear zones, the underground water level and the squeezing intensity the performance of hard rock TBMs was performed. Finally, double shield TBM for the excavation of Sabzkouh tunnel is proposed

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Ground-Penetrating Radar (GPR) is a non-destructive and high-resolution geophysical method which uses high-frequency electromagnetic (EM) wave reflection off buried objects to detect them. In current research this method has been used to identify geometrical parameters of buried cylindrical targets such as tunnel structures. To achieve this aim, relationships between the geometrical parameters of cylindrical targets with the parameters of GPR hyperbolic response have been determined using two intelligent pattern recognition methods known as artificial neural network and template matching. To this goal GPR responses of synthetic cylindrical objects produced by 2D finite-difference method have been used as templates in the neural network and template matching algorithms. The structure of applied neural network has been designed based on extracting discriminant and unique features (eigenvalues and the norm of eigenvalues) from the GPR images and predicting all geometrical parameters of the targets, simultaneously. Also the template matching operation carried out using two diverse similarity approaches, spatial domain convolution and normalized cross correlation in 2D wave number domain. The results of the research show that both two employed intelligent methods can be applied for in situ, real-time, accurate and automatic interpretation of real GPR radargrams, however in general the neural network method has led to less error and better estimation than template matching to predict the geometrical parameters of the cylindrical tar

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Because most part of Iran country is located in a dry climate, construction of water conveyance tunnels is inevitable. One of the major challenges in the construction of these tunnels is inflow of water into the tunnel during the construction and operation phase. The Rozieh water conveyance tunnel whose length is 3200 meters is a part of water conveyance project to the Semnan city and it is located 30 k NE of Semnan city. In accordance with the drilled boreholes, the tunnel route has been classified into eight zones from the geotechnical view. Then the permeability coefficients of host rock were calculated using back analysis approach on the basis of numerical simulation results and water inflow quantity during the construction phase. A parametric study was done on the lining and cement injection zone permeability and the thickness of cement injection zone. According to this study, the effect of injection zone thickness variation on the water inflow quantity is negligible. So with the assumption of 3 meters thickness for the injection zone, the permeability coefficient of host rock after injection were evaluated. Dependent on the initial rock permeability, cement injection could reduce the rock permeability 10 to 1000 times. In addition, the water inflow into the tunnel was calculated using hydro-mechanical coupling analysis. According to this analysis, the water inflow calculated by the hydro-mechanical coupling analysis is 50 to 70 percent less than the hydraulic analysis.

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The Schmidt hammer provides a quick and inexpensive measure of surface hardness that is widely used for estimating the mechanical properties of rock material such as uniaxial compressive strength and Young’s modulus. On the other hand, Schmidt rebound hardness can be used for a variety of specific applications. In the mining industries, it is used to determine the quality of rock, which is common practice when constructing rock structures such as those found in long wall mining, room and pillar mining, open-pit mining, gate roadways, tunnels, dams, etc. However, a number of issues such as specimen dimensions, water content, hammer type, surface roughness, weathering, testing, data reduction and analysis procedures continue to influence the consistency and reliability of the Schmidt hammer test results. This paper presents: a) a critical review of these basic issues and b) avaluate the effect of temperature, moisture and uniaxial compressive stress on Schmidt hammer hardness. It was found that water content has a significant effect on the Schmidt rebound hardness (SRH) of rocks. So that increase of water content substantially reduced the SRH of samples. Temperature also had a considerable influence on the SRH. However, relationship between SRH decreases with increasing temperature for tested samples were linear. Also tests results showed that uniaxial loading of samples increases the SRH values.

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./files/site1/files/4Extended_Abstract.pdfExtended Abstract
(Paper pages 73-90)
Introduction
Up to now, various indexes and methods have been presented for evaluating the abrasivity of rocks. In total, these methods can be divided to two main groups; the methods based on nature of rocks, methods based on heuristic tools. Schimazek F-abrasivity index is one of the most powerful and applicable indexes for evaluating the rock abrasiveness. This index uses the grain size, Brazilian tensile strength and equivalent quartz content for abrasivity analysis. Since the values of these parameters are equal in Schimazek index, therefore, in some cases this index doesn't have suitable ability to distinguish and classify the rock abrasiveness. This paper tries to modify the Schimazek index considering the weights of its applied parameters.
Material and Methods
In this research, Fuzzy Delphi Analytical Hierarchy Process (FDAHP) has been used to calculate the weight of dominant parameters in rock abrasivity. For this purpose several questioners have been distributed and the expert opinions were collected. The results showed that the quartz content, grain size and tensile strength have the weight of 0.4, 0.31 and 0.29 respectively and new Schimazek F-abrasivity index is as presented in equation (1).
    
In the next stage, in order to facilitate the application of new index, a new classification system was developed. This classification and related weighing graphs (Figure 1) help to change the discontinuous classification to continuous one.
Results and discussions
In order to verify the application of the new developed index, ten ornamental stones have been studied and the old and modified Schimazek indexes were calculated for all of them. Then, the cutting rate (sawing rate) of each stone was recorded in laboratory and the mathematical relationships between new and old indexes have been achieved. The results show that the new Schimazek abrasivity index has higher ability to predict the cutting rate than old one (Figure 2). 

 
Figure1. Continuous weighting for parameters of Schimazek F-abrasivity index


Figure2. Regression of old and new Schimazek F-abrasivity index with cutting rate of granite ornamental stones
Conclusion
Generally it could be concluded that, the main weakness of Schimazek F-abrasivity index which is the equality of parameters’ importance, has been removed by idea developed and confirmed in this study. The different weights which allocated to grain size, Brazilian tensile strength and equivalent quartz content in study, improves the Schimazek index applicability in rock engineering applications specially rock cutting and drilling. Therefore, it is recommended to use new method instead of old one in future applications.
 




 

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Introduction
The rock block volumes are formed due to the intersection of discontinuities in the jointed rock mass. The block dimensions affected by joint spacing, joint orientation, joint sets, are taken to be the most important parameters determining the rock mass behavior, strength parameters, and deformations. In the numerical modeling using distinct element method, the creation of the discontinuities can affect the final results very much. Using 3DEC software, it is possible to create joint sets in four conditions: regular and persistent, regular and non-persistent, non-regular and persistent, irregular and non-persistent. As an important point to consider, the major effect of block dimensions on rock mass behavior, strength parameters and deformation modulus can help to decide which one is most suitable to indicate the real conditions of rock mass. As explained in the previous studies, the use of persistent joints leads to the block dimensions being considered as small ones. In this way, due to the high strength of intact rock compared to the joints, the possibility of instability increases.
Material and methods
In this research, from quantitative point of view, Geological Strength Index (GSI) is calculated, based on block dimensions as an influential parameter, to consider the most appropriate case for creating joints in the numerical method. In this regard, according to valuable studies in Bakhtiari dam structure, the characteristics of discontinuities system and GSI of rock mass are utilized to come up with real conditions. Then, the modeling is done with different conditions of joints, block volume distribution, GSI for each case, and the results are compared with quantitative ones. And then the most suitable case for creation of joints in numerical modeling is suggested by using 3 DEC software, regarding the blocks volumes, type of distribution function, and GSI value. Also, the accuracy of this finding is investigated for other structures, independently of input parameters, by making changes in spacing, and joints persistence as two effective parameters in rock blocks dimensions. Owing to the difficulty in the accurate definition of joints persistence, which is related to dimensions of the location, the numerical models for joint persistence are done in an acceptable level in order to create blocks with high conformity in terms of the dimensions. Then, the comparison is made between block dimensions from perspectives of numerical models and GSI values, to choose the best ones showing high conformity with real conditions.
Results and discussion
The comparison of the modeling results using creation of joints in different cases with quantitative results obtained according to geological strength shows that the created block volumes are not properly distributed due to the creation of joints as irregular ones in the two cases of persistent and non-persistent. In this case, the blocks volume changes from a few centimeter to cubic meter, and as the block dimensions increase, the created blocks become bigger. Thus, according to the created blocks volume and the obtained GSI range, the creation of joints is not a suitable method as an irregular one. The creation of regular and persistent joints is not an appropriate method either, as the most created blocks are small, and blocks volume distributions do not comply with quantitative distribution. But with creation of joints as regular and persistent ones, the distribution function of blocks volume in numerical method and quantitative method is log normal. Therefore, according to the created blocks dimensions and GSI range using 3DEC software, the most suitable case is the creation of joints as regular and non-persistent ones. 
Conclusion
According to the obtained results in the four cases, when the joints are considered only as regular and non-persistent ones, the blocks volume range is more compatible with real conditions and follows log normal distribution. Thus it can be concluded that the suggested method for creation of joints in the numerical modeling using 3DEC software is more suitable than others considering the rock blocks dimensions and their distributions. This method can be utilized in any structure to accurately define the persistence of joints regarding created blocks dimension.

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Introduction
Rock mass deformation modulus is one of  the major parameters has to be considered in the design phase of arch dams. Due to filling and discharging of reservoir and corresponding loading and unloading on the dam abutments, irreversible deformation takes place within the rock mass and consequently, increases the potential of creating a separation between dam body and abutments. Therefore, the rock mass modulus must be more than an alowable value in order to prevent arch dam failure. Regarding small core samples and lack of joints and other similar discontinuities in samples, the determined modulus through performing laboratory tests is higher than those obtained through in-situ tests. The available technique to estimate the rock mass deformation modulus is divided into two classes as direct and indirect methods. In direct methods, the rock mass deformation modulus is measured via performing in-situ tests such as plate loading test while it is estimated through empirical equations using rock mass classification and laboratory test results in indirect methods. These equations are developed based on regression analysis between the rock mass modulus calculated via in-situ tests, the rock mass classification and laboratory test results. Although application of these equations is simple and cost-effective, the results are doubtful and cannot be used in the design phase of arch dam due to the heterogeneous nature of rock mass and rock type variability. The numbers of micro-cracks which are developed after gallery excavation using drilling and blasting technique are more close to the loading plate. Thus, calculated modulus in these points is lower than reality. The displacement in the points far from loading plate was near to zero while the transmitted load which is calculated applying ASTM D4394 standard is more than reality in small galleries. Consequently, the calculated modulus was extremely larger than real values and sometimes even more than intact value. The empirical equations are site dependent and they are just applicable in sites with similar geotechnical condition. It is obvious that in-situ tests, such as plate loading, are the appropriate method in order to determine the modulus of deformation, however, due to some simplification in the data processing such as semi-infinite boundary condition, the application of numerical simulation as a data processing tool is more appropriate. In this research, the Beheshtabad dam was introduced and the geology characteristics of dam site were investigated. Applying direct and indirect methods, the rock mass modulus of dam abutments is calculated.
Material and Methods
The dam site is placed approximately at a distance of 2.7 km from the intersection of Koohrange and Beheshtabad river. In accordance with geological studies, the rocks in the site could be categorized in four units combined of Dolomite, Dolomitic Limestone, Limestone, Marl and Marly Limestone. Applying empirical equation the rock mass modulus of dam abutments is evaluated based on the laboratory test results and rock mass engineering classification systems. In addition, ASTM D4394 is applied to investigate the results of ten plate loading tests which are executed in the right and left abutments. To interpret the plate loading test results in the right abutment, a three-dimensional Fast Lagrange Analysis of Continuum (FLAC3D) model is developed.
Result and Discussion
To process the numerical simulation results, back analysis as a data processing tool is used. In this approach, the input parameters of numerical model will be changed in the way that the measured quantities by extensometers at the monitoring points are almost equal with the computed ones via numerical model at the corresponding points. Based on the sensitivity analysis carried out on the Mohr-Coulomb failure criterion parameters, the friction coefficient and cohesion variation do not affect the displacements calculated via numerical simulation as the more portion of gallery displacements are elastic. The error function is minimum when the rock mass modulus is 12 GPa and the horizontal to vertical stress ratio (K0) is equal to 0.5. The evaluated rock mass modulus based on the numerical simulation is two times lower than corresponding one evaluated applying empirical equation as a result of empirical equation uncertainty. Consideration of stress decrement under loading plate shows lower level of stress decrement under loading plate in ASTM D4394 compared to numerical simulation. This is why, the rock mass modulus, calculated based on ASTM D4394, increases dramatically by getting distance from the loading plate. 
Conclusion
The empirical methods estimating the modulus of deformation based on rock mass classification systems tend to evaluate large value of modulus especially for the weak massive rocks.
As a result of galleries dimensions and semi-infinite boundary condition assumed in ASTM D4394, the calculated rock mass modulus increases dramatically by getting distance from loading plate. Therefore, the numerical simulation was applied to process the plate loading test results. A new normalized error function was developed based on measured displacements and the rock mass modulus in the right abutment was determined 12 GPa which is very lower than the calculated value using ASTM D 4394. Also, as a result of numerical simulation, the rock mass is uniform. The stress increment perpendicular to the loading plate was calculated applying numerical simulation which is 0-90 percent lower than those suggested by ASTM D 4394. 
 

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Introduction
Series A of coarse-grained alluvial deposits of Tehran are extended in eastern and north-eastern areas of Tehran. Analyzing and studying of these alluvial deposits from a geological point of view as well as their creation time and general characteristics such as the deposits’ mineral types, their source, and formation conditions, gives a better point of view to geotechnical engineers about exploring their characteristics as well as geotechnical aspects in underground structure design, excavations, and foundation design processes. On the other hand, in order to analyze stability, estimating the factor of safety and the seismic design of these structures, considering their location, which is in Tehran with a high seismic hazard area, the necessity of knowing the exact mechanical and dynamic properties of Tehran's alluvium is felt more than ever.
Material and methods
Due to the grain size of Tehran’s coarse-grained alluviums (series A) as well as high level of cementation of them, it is impossible (or maybe so difficult) to make undisturbed samples in order to do experiments. Such that it is excavated 23 boreholes with 30 to 140 meters depth as well as 17 test wells with 20 meters depth in an area which was extended in 10 kilometers in long which were located in Tehran’s No. 13 and No. 14 districts (as it can be seen in Figure 1). During the excavation of the entrance ramp and tunnel of eastern highway of Tehran, in-situ tests have been done in different sequences. Since it was important to investigate real behavior of these alluviums, different in-situ tests such as plate load test, in-situ shear test, pressuremeter test, and downhole test have been done as well as many laboratory and field tests. Furthermore, (1) X-Ray Diffraction (XRD) and (2) X-ray Fluorescence (XRF) as well as (3) Scanning Electron Microscopy (SEM) methods, have been used to explore the type of minerals and those used in cementation.
 
 
 
 

(ب)
 
 
 
Figure 1. a) Geological plan and the location of boreholes and test wells in the alignment of East Tehran Freeway
Results and discussion
Based on the results of XRD tests, it is quite clear that the largest weight percentages of tested samples are lime and silica.
Calcium and magnesium levels-as the high-power cations in flocculation process-in soil sample No. 1 (soil with high cementation level) are much more than soil sample No. 2 (soil with moderate cementation level).
This is the cause of high cementation level of soil sample No. 1 comparing with soils sample No. 2. A rapid increase in stress level can be seen in in-situ shear test results, in low shear displacements, up to reaching a maximum of τ_p (peak point) and afterwards reduction in shear stress with softening behavior.  
Cohesion and shear strength levels also increase by increasing the depth. According to the plate load tests results, an increase in soil modules changes can be seen in different depths by depth increasing.
Large tendencies to increase in volume and dilation can be seen in under shear load cemented soils, after applying a primary compression on them. A brittle behavior with the occurrence of a certain peak can be seen in cemented samples. The significant increase in strength is directly related to the severe dilation rate, which can be seen in cemented samples results.  The shear strength would be decreased, if this cement is broken during the particles’ displacements.
The results of downhole tests are shown in Figure 2. According to this figure, it has been explored that V_s,30 is about 600 m/s in moderate cemented soils while it is about 850 m/s in highly cemented soils.  Because of the homogeneity and uniformity of sedimentary deposits, shear wave velocity is increasing due to the higher density of the layers and high level of cementation in both of the soil types. However, this increase is not significant at depths above 25 meters.
Conclusion
Based on the results, cementation level of the eastern coarse-grain-alluvium of Tehran is moderate to high and minerals used in cementation of this type of soil are generally carbonated and especially calcite.
Investigating the level of cementation of soil as well as the results of chemical analysis and in-situ tests, it can be found that the strength and deformation parameters of the soil are directly related to the degree of its cementation.
Based on the obtained results, the deformation modulus increases by about 25%, the cohesion by about 55% and the shear wave velocity by about 30% with increasing the degree of cementation (Table 1).
Increases of these parameters are directly related to depth. However, the cementation level does not significantly affect the internal friction angle of the soil.
Table 1. Average results of in-situ shear tests

Deformation Modulus (MPa)	Peak Friction Angle (deg.)	Cohesion (kPa)	USCS	Depth (m)	Sample
50-60	39	30-35	GW-GM	5	Moderately Cemented Soil (M.C. Soil)
75-85	41	50-60	SP-SC	10
85-90	41	50-60	GW-GC	15
95-105	41	50-60	GW-GC	20
60-70	39	35-40	GW-GM	5	Highly Cemented Soil (H.C. Soil)
75-85	39	50-60	GW-GC	10
110-120	42	65-75	GW-GC	15
125-140	41	110-120	GC	20

 
 

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