Journal of Engineering Geology

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 Knowing the engineering geological characteristics of carbonate formations is necessary for database. In this research, using petrological study and mechanical tests on 5 types of Ilam-Sarvak formations limestones in Khorramabad city, their engineering geological characteristics were determined and the relationship between physical and mechanical properties have been analyzed. IBM SPSS Statistics (version 19.0) software was used to determine the required relations. The relations have high correlations. Based on the studies on this of thin sections, rocks are characterszed as biomicrite. Limestones of Ilam-Sarvak formations have high hardening and low porosity. These rocks are in medium to high density, very resistant durability index, medium to high UCS and high point load strength category. The rocks are also impermeable. Based on the UCS, modulus ratio of the intact rock, the limestones are CM and CL. According to solubility test, the solution velocity constant was 1.39×10^-6 m/s.

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This paper presents a case study of the instability mechanism, to verify and reinforcement method adopted construct collapsed zone of Sabzkuh water conveyance tunnel in southwest Iran. The instability problems were encountered during tunnel excavation due to the failure, changes in stress field lead to deformation causing dilation and increasing the permeability of sand and gravel layers, local fault gouge zones, landslide and in turn significant reduction in shear strength and collapse in tunnel. IPE Arch Support Technique (IAST) was, used for T1 part of Sabzkuh tunnel zone in order to reinforce the ground around tunnel and to cross the zone falling. In this study, Finite Element Method was employed for the quantitative reinforcement effect with deformation modulus of ground, IPE length and size. As a result, the settlement increases as length increases and decreases with the increase of the deformation modulus of ground and IPE size.  

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 In this research, prediction of concrete strength containing different aggregates using Non-destructive (Ultrasonic) testing through Artificial Neural Networks was carried out. For this purpose, aggregates with different properties were selected from the quarries, and then their destructive and nondestructive properties were obtained in laboratory. The significance of this research, using different aggregates with physical, mechanical and chemical properties also used two different test methods, such as Non-destructive static and dynamic testing, which are respectively uniaxial compressive strength and compressive wave velocity. Thus, this model includes various types of samples and the prediction model includes static and dynamic tests. The results showed that the use of artificial neural networks not only increases the accuracy, but also it reduces costs and time.

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As usage of reinforced soil structures is highly increased in seismic active zones, the analysis of dynamic behavior of these structures begins to be of great significance.  The present paper is an attempt to study the seismic behavior of reinforced soil retaining walls with polymeric strips. The consequences of the most principal parameters counting the length of reinforcement, reinforcement arrangements (zigzag vs. parallel), maximum base input acceleration and wave frequency on the wall displacement have been investigated for sensitivity analyses. The main drawback of numerical methods in dynamic analysis is being very time consuming. Therefore, determination of equivalent coefficients is a suitable, easy and beneficent approach to converge   results of   pseudo-static and dynamic methods. In this case, a relatively accurate design is achieved by using pseudo-static method that takes less time. To this end, an earthquake equivalent horizontal acceleration coefficient is proposed by considering horizontal displacement of the wall as the basis for comparison

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The in-situ stress is one of the most important parameters in the design of underground structures. Conventional methods such as in-situ stress measurements using hydraulic fracturing method has two main disadvantages are time and cost of this methods. Acoustic emission is one of the indirect in-Situ stress measurement methods which is based on the theory of the Kaiser effect. When a rock is stressed, it release acoustic signals this phenomenon is called acoustic emission. Kaiser Effect is defined as lack of acoustic signals in the lower stress levels than the previous maximum stress level. In other words, as long as rock is not reached to the previous maximum stress level, do not show significant acoustic emission. Several factors affect on Kaiser Effect such as delay time, temperature, rock fabric, porosity, discontinuities, joints and geological structure. In this paper, effect of the delay time on Kaiser Effect has been presented. The time between coring operations and acoustic emission test is called delay time. The limestone rock is selected as main samples of test and after preloading, reloading and acoustic emission test were carried out with different delay times. The results showed that the felicity ratio is less than 1, when delay time is about 20 days and after three months has increased to be more than one.

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Marly rocks of Abtalkh formation were classified by Q, RMR, RSR and RQD rock mass classification systems using 222 meters logs from exploratory boreholes in Doosti dam site. The results show that the RMR is the most suitable method for classification of studied rock masses and has highest correlation coefficient with RQD. The validity of different Q-RMR equations was studied using error ratio (ER). Cameron et al. (1981) and Morno (1982) equations have lowest ER and highest validity for studied marlstones. Bieniawski (1989) and Cameron (1981) relationships are lower and higher limits of equations for marly rocks respectively. 

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Ground settlement due to tunneling and the effects of the engineering geological factors on its dimensions and extensions, is a very important problem in shallow tunnel excavation projects in urban areas. Empirical method is one of the usual methods to study this subject. The empirical and dimension-less parameters of VL and k are the most important parameters in relation to this method that are estimated according to engineering geological factors. In this research, the values of these parameters were initially estimated based on preceding studies and the ground settlement was predicted using these estimated values of VL and k. In next stage, the results of predictions were compared with the real (measured) settlements happened due to Abuzar tunnel excavation. As the real settlements are less than the predicted ones, it was concluded that the real VL must be lower than the predicted values or the real k must be higher than the predicted values. With regard to the high dependency of these parameters to the soil cohesion, it seems natural cementation of Tehran alluvia has acted as a factor to increase the soil cohesion and has caused to decrease ground settlement due to excavation of Abuzar tunnel. For validation of this hypothesis, preceding findings about alluvia cementation were reviewed and the results of in-situ and laboratory shear and triaxial tests were compared with together. Then it is concluded that the higher cohesions of in-situ shear tests are occurred due to natural cementation of materials existing in Abuzar tunnel route

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Evaluation of the excavation-induced ground movements is an important design aspect of supporting system in urban areas. This evaluation process is more critical to the old buildings or sensitive structures which exist in the excavation-affected zone. Frame distortion and crack generation are predictor, of building damage resulted from excavation-induced ground movements, which pose challenges to projects involving deep excavations. Geological and geotechnical conditions of excavation area have significant effects on excavation-induced ground movements and the related damages. In some cases, excavation area may be located in the jointed or weathered rocks. Under such conditions, the geological properties of supported ground become more noticeable due to the discontinuities and anisotropic effects. This paper is aimed to study the performance of excavation walls supported by nails in jointed rocks medium. The performance of nailed wall is investigated based on evaluating the excavation-induced ground movements and damage levels of structures in the excavation-affected zone. For this purpose, a set of calibrated 2D finite element models are developed by taking into account the nail-rock-structure interactions, the anisotropic properties of jointed rock, and the staged construction process using ABAQUS software. The results highlight the effects of different parameters such as joint inclinations, anisotropy of rocks and nail inclinations on deformation parameters of excavation wall supported by nails, and induced damage in the structures adjacent to the excavation area. The results also show the relationship between excavation-induced deformation and the level of damage in the adjacent structure.

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of initial texture and plastic fine content has been investigated. In order to model the different deposition condition four different specimen preparation methods are used. The tests are conducted on sands and its combination with to 25 fine percent using static and cyclic method. Four different specimen preparation methods are used consisting of Dry Funnel Deposition (DFD), Water Sedimentation (WS), Moist Tamping (MT) and Air Pluviation (AP). Each method may be useful to model the behavior of some special deposited soils. For example, DFD is the best method to model the natural deposition of silty sands, while the WS method is suitable for simulating the sands natural deposition in the rivers. MT method is the best method to simulate the behavior of compacted embankments while SD method is suitable to prevent the segregation of particles with respect to other methods like Water Pluviation. Effect of sample preparation methods on the sands and silty sands behavior is investigated to some extent, while the clayey sands are rarely considered. The results show that water sedimentation method, Air pluviation method and Dry funnel deposition method tends to create dilative textures with continuous dilative behavior even in high clay fine content. In contrast, the wet tamping method shows the dilative behavior only for clean sands specimens and increasing fines will results in instability and complete strain softening behavior. In cyclic loading the difference between different methods are less with respect to static loading. It seems that the results of different methods tends to be identical with increasing in fine content. In general, increasing fine content up to 20 percent results in more instability. After that a threshold value can be estimated bout 2 percent, after that the instability becomes less with continuous increase in fines content. The valuable result is that the threshold value is not dependent on the specimen preparation method or initial texture of specimens. 

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Introduction
Artificial stone is a type of building material that consists of natural aggregates, binders, such as cement or polymeric resin and some additives. The aggregates used for the production of the artificial stone are generally supplied from the wastes and scraps of quarries and industrial stone manufactories. Accordingly, the produced rock has a significant economic value.
The mixing design includes more than 80% of natural aggregates and less than 20% additives and binders, such as various types of polymer resin or cement. Due to the fact that artificial stones are designed purposefully and according to engineering patterns, so the stone has different designs and colors and thus can meet the diversity of consumer desire and is an appropriate alternative for natural stones in the building industry. Due to a large number of various rock mines and industrial workshops in Iran, it has the ability to produce artificial stones.
Material and method
The purpose of this paper is to investigate the effect of silicate aggregates on the properties of artificial stones, the aggregates of the three types of natural stone tuff, andesite and granite were selected. The basis of this selection is the mineralogical variety, the textural diversity and the easy accessibility of these three stone types. The binder used in the manufacture of these artificial stones is an unsaturated polyester resin, accounted for 11% of the samples. The crushed and graded samples were poured into the mold after mixing with resin from 85% to 15% and were subjected to a compression pressure of 12 MPa for 24 hours.
Results and discussion
The summary of the results of the experiments carried out in Table 1 is presented.
Table 1. Summary of the results of the experiments on the samples

Rock type		Water absorption percentage	Point load index	Uniaxial compressive strength	Brazilian tensile strength	Weight loss (5 cycles)
Tuff	Natural	4.84	10.57	145	21.53	-0.0172
	Artificial	11.48	6.19	63	12/66	-0.0126
Change rate		▲	▼	▼	▼	▼
Andesite	Nature	1.35	10.48	84	12.83	0.0046
	Artificial	8.47	1.83	34	5.86	-0.0417
Change rate		▲	▼	▼	▼	▲
Granite	Nature	3.01	1.82	41	10.10	-0.0032
	Artificial	0.42	3.56	51	10.34	0.0083
Change rate		▼	▲	▲	▲	▼

By reviewing the results, it can be seen that the sample of artificial granite has all the desired indices of a building stone. In comparison to natural granite, the percentage of water absorption and its weight loss is lower; conversely, the point load index, uniaxial compressive strength, and tensile strength of the Brazilian are more. Electronic image observations also show more homogeneity between resin and aggregates but on the other hand, artificial tuff and andesite haven’t got favorable indices, in comparison with natural stones.
Conclusion
The conclusion of the research can be summarized as follows:
The following results were obtained by the preparation of three samples of artificial stone from three types of natural stones: Tuff, andesite and granite, and performing physical and mechanical tests and studying the mineralogical and texture characteristics of the stones:
Mineralogical studies by a polarizing microscope and XRD irradiation analysis showed that the texture of both tuff and andesite contains unstable minerals such as opal and glass materials (amorphous), alongside other minerals. On the other hand, they have a microcrystal texture that includes abundant empty spaces. In contrast, granite is mainly composed of quartz, feldspar and biotite minerals, and the stone fabric has a coherent crystalline structure.
Artificial granite has all the desired indices in comparison to natural granite. That way, the percentage of water absorption and its lost weight are reduced; on the contrary, the point load index, uniaxial compressive strength, and Brazilian tensile strength increase. While artificial tuff and andesite’s indices are not favorable in comparison to natural stone. On the other hand, their water absorption has increased, while their resistance index is lower than the natural stone. The lost weight of these two samples also shows varying conditions.
SEM electronic images taken from the artificial granite sample show good homogeneity between resin and aggregate compared to natural granite while artificial andesite and tuff specimens show the presence of empty spaces and dispersed resin materials.
Thus, it is concluded that the artificial stone samples made from granite aggregates are more suitable for mineralogical, physical and engineering properties than andesite and tuff../files/site1/files/123/2Extended_Abstract.pdf

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Introduction
Pressure tunnels in hydroelectric plants are used to convey water to powerhouses. These tunnels are the sources of seepage flow to the rock formation, thus, during the water filling, they will have a low resistance to seepage and, by increasing the internal water pressure of the tunnel, the inflow force will be transferred to the rock mass. In these conditions, the cracks, pores and all other elements of the rock mass are affected by the seepage forces in all directions. This hydro-mechanical interaction affects changing the stresses and displacements of the rock mass around the tunnel and causes modifications in the permeability of rock elements during the water filling. Therefore, changes in stress distribution lead to alterations in the permeability coefficient and redistribution of the seepage field. In these conditions, since the analytical solution of the problem is not possible, the numerical analysis based on the finite element method has been used in this study.
Material and methods
In this approach, the rock mass is considered as an equivalent continuum in which the effects of discontinuities are taken into account in its material behavior. High-pressure tunnels under internal water pressure requires reinforced concrete lining to prevent hydro-fracturing. The ABAQUS software is capable of analyzing such as seepage from the tunnel, modeling of the steel bars in concrete, and taking into account hydro-mechanical interaction. Thus, the software is used for numerical analysis.
The pressure tunnel of the Gotvand dam and hydroelectric power plant (HPP) scheme is taken as a case study for the numerical simulation. Pressure tunnel of the Gotvand dam located in the southwest of Iran is taken as a case study for the numerical simulation. Among behavioral models in the software, Mohr-Coulomb failure criterion is considered to describe the rock mass, but the principle of effective stress determines the rock mass behavior. Since the concrete lining of the pressure tunnel will undergo two mechanisms of the cracking due to tension and the crushing due to compression, concrete damaged plasticity model is used to predict the response of the concrete elements. The evolution of the yield surface of the concrete lining is also controlled with tensile and compressive equivalent plastic strains, correspondingly.
In this study, the hydro-mechanical interaction is implemented based on the analysis of the pore fluid/deformation analysis, and the direct-coupled method is used to solve the governing equations of the problem. To verify the proposed model, the elastic behavior of the media is simulated to compare the numerical and the analytical solutions and good agreement is obtained. The numerical analyses are carried out the hydro-mechanical interaction with constant permeability coefficient. When cracks develop in the concrete lining at high water pressure, the properties of the concrete lining change and as a result, the stress dependent permeability of the lining and surrounding rock mass in pressure tunnels should be considered. The coefficient of permeability controls the rate of seepage flow in porous and fractured media. Although permeability represents an original property of the porous media, it can be modified when subjected to the stress variations. Instead of changing aperture, the change in the void space or volume is the typical consequence that results to change the permeability coefficient. In order to bring the model closer to the real conditions and in the validation of the new model, the influence of the permeability coefficient variations of the concrete and rock mass on the deformations and stresses of the model has been added to nonlinear analysis by USDFLD code. Increasing the water head in the tunnel during water filling is also considered with the combination of DLOAD and DISP codes in the model.
Results and discussion
Since the lining and rock mass have nonlinear properties and complex behavior, for verification of the model in ABAQUS software, the model is simulated with homogeneous, isotropic and elastic behavior. The results of seepage flow on the interface of the concrete lining and rock mass obtained by analytical and numerical solutions indicate that there is a ±5 % difference between them. Then, the results of the elastic behavior of the model show a good agreement with the results of analytical solutions. Therefore, this numerical model has been employed for the nonlinear analyses.
Finally, the optimal thickness of the concrete lining with the appropriate arrangement of the reinforcement in the reinforced concrete linings is utilized to minimize water losses from the tunnel based on the new model. Thus, the results of the analysis with the aim of reducing the water losses from the tunnel indicate that the suitable arrangement of the steel bars in the concrete lining leads to the distribution of micro cracks in the lining, and the reinforcement stress stays at a lower value with high internal water pressure. Based on the new numerical model, it is suggested that the lining should be designed with the thickness of 40 cm and the reinforcement with the diameter of 16 mm and the spacing of 20 cm.
 Conclusion
The results of the numerical model indicate that to control the seepage outflow from concrete-lined pressure tunnels, the thickness of the lining and the suitable arrangement of the steel bars in the concrete lining play a significant role in preventing excessive seepage from the tunnel./files/site1/files/124/3dadashi%DA%86%DA%A9%DB%8C%D8%AF%D9%87.pdf

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Abstract
This study aimed at evaluating the effect of calcic aggregates of engineering geological properties on the artificial stones properties, non-resin cemented and then, to make a comparison between the engineering properties of artificial and natural stones. To investigate the effect of calcic aggregates properties on artificial stones, seven samples of building stones including black limestone, three samples of marble (Chinese stone, marble and crystalline marble) and two samples of travertine and onix were used. Engineering geological properties of the samples were then determined. In the next stage, after designing mould for constructing artificial stones, aggregates with the same grading and mixture design were provided. Then two samples including coarse and fine grained artificial stones were made for all of the mentioned aggregates under the same vibration, pressure and vacuum conditions. Next physical, strength and durability tests were conducted, and the obtained results were compared. The results of engineering parameters showed that Hojjat Abad travertine artificial stones have similar engineering quality to own natural stone and Crystaline Marble and Turan Posht travertine artificial rocks have about 11 to 32% increase in quality but Chinese stone, Black limestone, onix and marble have a 6 to 33% lower quality than own natural stone. However, the samples made of other stones in view of the compared parameters related to artificial stones have lower quality than natural stones; however, they are placed in the acceptable range as building materials.
Introduction
Given the variation of construction materials, the importance of the economy in its supply and large use of natural stone mines and the production of seemingly unusable slags, it is necessary to reuse these slags. One of these reusing methods is to make artificial stones and its application as construction materials. Rock powder, aggregate, a small amount of cement or resin and other chemicals are used for producing artificial stone. In this study, carbonate minerals, rock powder and white cement in the first phase are mixed and wet. Then, in the next stage, to form the sample in a cubic mold, they have been compacted under three physical processes of vibration, vacuum and pressure. The aim of this study is to investigate how to make artificial stone, to evaluate the engineering properties of artificial rock and the effect of limestone engineering properties on artificial stone properties of non -resin cement and then comparing the properties of artificial rocks made with natural stones
Material and methods
In this study, in order to investigate the effect of calcic aggregates properties on artificial stone properties, seven samples of building carbonate rocks including crystalline marble, two samples of marble, black limestone, and two samples of travertine and onix were used.
Engineering geological properties of the used samples were then determined. In the next stage, after designing mold for constructing artificial stones, aggregates with the same grading and mixture design were provided. Then two samples including coarse and fine grained artificial stones were made for all of the mentioned aggregates under the same vibration, pressure and vacuum conditions. After construction, physical, strength and durability tests were conducted, and then the results were compared.
Results and discussion
Investigation of the effect of engineering geological properties of carbonate aggregate on artificial stone properties showed that the artificial stones made of travertine aggregates have higher quality than natural travertine in terms of physical, strength and durability properties. Due to the existence of pores on the surface of travertine aggregates, the used cement can result in reducing effective porosity and increasing strength and durability in the artificial stones.
In Table 1 a proposed research has been used for rating rock engineering parameters based on the degree of importance for building stones. Then, according to this table, the score of each natural stone and related artificial stones were determined. For building stones, the importance of durability and strength is more than the density.  Also, the density shows its effect on durability. At the same time, with increasing the percentage of water absorption, the durability of rock has decreased. Therefore, the rocks with less water absorption are more important.
Table 1. Scoring of building stones based on the engineering parameters

Parameters	Description	Excellent	Good	Marginal	Poor
	Total score	100	75	50	25
Water absorption (%)	Range	0-2	2-3	3-5	>5
	Score	25	20	15	10
Unit weight (kN/m3)	Range	>24	22-24	18-22	<18
	Score	15	10	5	3
Uniaxial compressive strength (MPa)	Range	>50	40-50	30-40	<30
	Score	20	15	10	4
Tensile strength (MPa)	Range	>20	15-20	10-15	<10
	Score	20	15	10	4
Durability (%)	Range	<1%	1%-2%	2%-3%	>3%
	Score	20	15	10	4

The total score of fine-grained artificial stones (65%) is almost similar, indicating that the type of carbonate grains does not affect the characteristics of fine-grained artificial stones, but the total score of coarse artificial grains are in the range of 58 to 74%. This range of score indicates that structural weakness, especially the cleavage surface, porosity, lamination, vein and acetylolite of aggregates have more influence on engineering properties in coarse-grained artificial rock.
Conclusion
Comparison between the engineering properties of artificial and natural stones were studied. The following conclusions were drawn:
- The artificial stones of Hojjatabad travertine have similar engineering quality with their natural stone.
- Both Crystaline marble and Turan Posht travertine artificial rocks have about 11 to 32% increase in quality but Chinese stone, black limestone, onix and marble have 6 to 33% decrease in quality compared to natural stone but in acceptable ranges when they are considered as construction materials.
- The samples made of other rock samples have lower quality than natural stones; however, they are placed in the acceptable range as building materials../files/site1/files/144/Mirjalili.pdf
 

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