http://jeg.khu.ac.ir Journal of Engineering Geology - Journal articles for year 2011, Volume 4, Number 2 Yektaweb Collection - https://yektaweb.com en 2011/5/11 http://ndea10.khu.ac.ir/jeg/browse.php?a_id=348&sid=1&slc_lang=en One of the main methods of determining dispersive potential of clay is chemical tests. These tests are found on the basis of sodium ion as a main chemical element in dispersive clay. The examinations show that there is no correlations between results of physical tests and chemical criterions. In present research after preparing the results of tests on 18 borrow pit sources of clay materials of earth dams, we investigate the Dr. Rahimi&#039s criterion with results of Pinhole Test and then bases on pinhole test results, we suggested the modified criterion of Dr. Rahimi&#039s proposed general criterion. The results of investigations on the range of laboratory data shows that the correlations of Dr. Rahimi&#039s proposed criterion with pinhole test is 63%, while this rate is 74% for our suggested modified criterion. Also it should be considered that Dr. Rahimi&#039s criterion compiled according the results of 24 laboratory samples while suggested criterion in present research compiled according the results of 234 laboratory samples. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=349&sid=1&slc_lang=en A regular set of large scale direct shear tests were performed to study gravel particle effects on shear strength characteristics of sands. The tests were conducted using direct shear apparatus with 300 mm × 300 × 170 mm shear box. Uniform, fine sand was used as the base material and mixed with 20, 40 and 60 percent of angular and rounded gravel grains with maximum size of 12.5 and 25.4 mm as oversized particles. All tests were performed on dry samples in drained condition. Samples were prepared in a relative density of 60 percent and tested using three surcharge pressures of 150, 300 and 450 kPa. According to the results, mixtures with angular and larger gravel grains show more shear strength and dilation compared to the mixtures contain rounded and smaller oversized particles. Enhancement of gravel content increases the effects of oversized particle on shear behavior of mixture. In this regard, some correlations for estimation of mixture&#039s friction angle and shear strength were suggested based on gravel type and gravel content. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=350&sid=1&slc_lang=en The Alborz dam rock foundation is composed of marl and sandstone. With regard to the proposed plan for the grout curtain in marly rocks (relatively soft and plastic( which is significantly different from the hard and brittle rocks, the boreholes spacing (influence radius slurry), injection pressure (resistance rock), and even the composition and concentration of slurry are important. In the present paper, in order to evaluate the grout curtain of Alborz Dam, emphasis has been placed on two important parameters, namely, the coefficient of permeability and cement take. The results of cement take suggest that the distance between the primary boreholes is long and there is no proper connection between the primary and secondary boreholes. Moreover, grouting results of the fifth and sixth series of grout holes imply that the depth of some of the sixth series of grout holes has not been attained at the water tightening surface. A review of the rate of the cement take - time - pressure graphs and cement take - time graphs on the right abutment indicates that the injection pressure has not been applied in accordance to marly rocks leading to unfavorable phenomenon of opening and closing of joints (hydrojacking). Notably, the check holes results on the right abutment indicate that water tightening at this area has been provided a satisfactory and acceptable job. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=351&sid=1&slc_lang=en The main objective of this research is to provide information about the effects of mineralogical characteristics of aggregates on concrete properties. Crushed aggregates were selected with different petrographics from different resources. Aggregates such as, Marble, Dolomite, Tuff, Granite, Genasis, Basalt, Andesite, Lumashele, Sand Stone and Diorite which have different chemical, physical and mechanical properties were used in this study. The results of the study showed that physical and mechanical properties of minerals control properties of concrete and undesirable properties of concrete influenced with which of mineral. Also, the results indicated that aggregates with flaky and elongated minerals subjected to weathering have a great effect on undesirable properties of concretes. The highest uniaxial compressive strength (33 MPa) at 28 curing days was measured in the specimens prepared with dolomite aggregates while the lowest strength (13 MPa) was measured in the specimen prepared with lumashele aggregates at the same age. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=352&sid=1&slc_lang=en One of the most important issues in the Reverse Analysis is analyzing the density resulting from the compaction of in fine soils. The conventional methods in d etermination of soil density are: sand cone, rubber balloon and nuclear density gauge. Trained neural network, as a suitable alternative for conventional methods based on models analyzed by those methods, is not only as accurate but it is also easier to calculate and implement. In the present article, a model based on multilayer perceptron of neural network is presented for prediction of the behavior of fine soils density in Sarabi Dam. The paper presents the implementation process and density of the soil layers. The input variables include 4 geotechnics and 4 implementation parameters. The geotechnic parameters consist of: optimum moisture content, maximum specific gravity, liquid and plasticity limit implementation parameters consist of: the number of cross rollers, thickness of the layers and density and moisture of the soil obtained from the site. The model is based on multilayer neural network, using the error back propagation approach and it is capable of calculating the density. As a result, the maximum specific gravity laboratory, using the aforementioned geotechnic and implementa-tion parameters, is presented. The method compates the maximum specific gravity laboratory accurately at almost 100 percent. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=353&sid=1&slc_lang=en Huge amount of scarp tires have made a big environmental problem that its reduction assessment is an important aim for researchers. Reusing of these materials in different branch of industrial is concentrated. Because of elastic behavior and absorbing the energy, waste tires are concerned as a famous damper. As a more effective manner to check the seismic forces is reducing the entered movements to the structure, it seems that using soil-scrap tire mixtures acts as seismic damper and these mixtures can reduce the earthquake forces acting to the structure. In this research this mixture is modeled as a damper under the foundation and the bed rock depth is analyzed in both time and frequency domains. Obtained results show that using soil-tire mixture reduces the resonance amplitude, energy and the acceleration reached to the ground surface. It should be mentioned that increasing the depth of the bed rock, the act of the mixture as a damper reduces. The results show that this mixture has a better operation in strong ground motions. Using these materials is cheaper compared with other base isolation systems, more available, not requiring high technology and also it reduces both earthquake forces and environmental problems. http://ndea10.khu.ac.ir/jeg/browse.php?a_id=354&sid=1&slc_lang=en In this research, it is attempted to develop a new classification system for evaluating the rock sawability with respect to affective and major parameters. In this new classification system, four major characteristics of rock are selected for evaluating the rock sawability. In total, each rock takes a new score from 10 to 100 and classified into five classes: very poor, poor, fair, good and very good by new classification system. The new calculated rock sawability index (RSi) can be use as a useful index for evaluating the rock sawability. In the present paper, the relationship between ampere consumption, RSi and machine parameters are investigated by multiple regression. For this propose, 12 stones are tested by new sawing machine under different machining conditions (different depth of cut and feed rate). The results of this step are used as input data in SPSS software. Finally, two predicted models are presented with respect to machining parameters and RSi. These new models in stone factories can give a good viewpoint of energy consumption