نشریه زمین شناسی مهندسی ایران
سال پنجم شماره 3 (پاییز و زمستان 1391)

This paper deal with to investigation of the results of mineralogical and geotechnical studies on lime–stabilized soft clay soils in the southwest of Hamedan. In this order, the hydrated lime was added in the order of 1%, 3%, 5% and 7% by weight and laboratory experiments including mineralogical studies, grain size distribution, plasticity limits, compaction and uniaxial compressive strength were conducted on samples after 7, 15, 30 and 45 days of curing time. The test results indicate that increasing the lime percentage, the soil gradually loses it's plasticity characteristics and finally, it is non-plastic. In addition to, increasing the added lime and curing time, the compressive strength and elasticity modulus of the lime - treated soils increases. Based on the test results was determined that by addition of 7% lime and after 30 days curing time, the studied soft clay soil is stabilized as satisfactory. Therefore, the optimum lime content and proper curing time for lime-treated soils is 7% and 30 days, respectively. Also, In order to investigation of relationship between lime-treated geotechnical properties with lime percentage and curing time, the multivariate regression analysis has been carried out that the results demonstrate high regression coefficients for the proposed relationships.

One of the methods for evaluation mechanical characteristics of intact rock is studying on rock single particle strength. In these paper, single particles loading apparatus was introduced then design stage and component this apparatus was described. Repeatability test results from static and penetration test on homogeny particles were investigated and behavior charts this samples were drawn. Samples photographs before and after tests were taken and particles fracture mechanism were described. For investigation repeatability test results, collective behavior graphs were drawn and were compared to each other and validation degree of results by using small sampling theory were evaluated. For evaluation the performance apparatus and results in estimating the UCS, 480 single particle loading (SCSI) of micro-crystalline limestone determined and compared with UCS, then presented relationship between them with correlation of coefficient larger than 0.83. This subject shows the ability apparatus in UCS indirect prediction.

It is important to determinate the elastic modulus of intact rock in many engineering projects relating to rock such as tunnels, slopes and foundations. Determination of this parameter need of high quality core samples and sophisticated test equipment because these make performing this test difficult and costly. There for in current years, researches have tried to produce relationships for prediction of this parameter using physical and index characteristics of rocks. So here an attempt has been made to predicate the elastic modulus of limestone by uniaxial compress strength, porosity and longitudinal wave velocity. So we used multiple variable regression method and perceptron artificial neural network with 3-4-1 architecture. Data base contains 123 samples that 70% and 30% of them has been used for train and test respectively in ANN. The models have been compared using coefficients of R2, RMSE and VAF. The coefficient of determination (R2) using multiple variable regression was 0.738. it was 0.805 and 0.832 for ANN train data set and ANN test data set respectively. This shows the ANN method have more accuracy than regression.

Long-term rock deformation is one of the critical problems in rock engineering design. This study presents results of some laboratory creep tests for assessment of time-dependent behavior of two rocks with different brittleness: Sandstone as a semi-brittle and Marble as a brittle rock. Brazilian disk specimens are used to plan some indirect tension creep loading tests. Also, Single Edge Crack Brazilian Disk (SECBD) is employed to evaluate the effect of pre-crack on the creep behavior of rocks. Totally, 12 creep loading tests are performed on the two rock types with three loading severity. Result of experimental tests indicates that failure time reduction percent due to existence of pre-crack in Marble specimen is more than Sandstone. In other words, the effect of pre-crack on the reduction of failure time and strain is more noticeable in more brittle rock.

Accurate determination of geotechnical and geological parameters of rock mass was performed using geotechnical exploration results including, the laboratory and in situ tests, empirical relations, geological surveys and field observations. The rock masses along penstock tunnels of Rudbar-Lorestan have a complex geology and consist of Dalan, Hormoz and Mila formations, mostly composed of shale, marl, marly limestone to limestone and dolomite. In this study, based on the measured data, the rock masses along penstock tunnels were classified by engineering classification systems of RMR, Q and GIS. And, a new relationship between RMR and Q for the studied area was presented. There were various empirical relations between RMR, Q and GIS, that were used for estimating geotechnical parameters. It must be noted that each of the empirical relations found may produce proper results for special regions. In this paper, the deformation modulus, cohesion and friction angle of Dalan formation were evaluated using the results of in situ dilatometer tests, laboratory tests, and findings of more than 25 geotechnical exploration boreholes in Dalan formation. Afterwards, by calibrating the empirical equations through the measured data, the geotechnical parameters of Mila and Hormuz formations were accurately estimated.

In engineering geology the organic soils are classified as problematic soils. Because of the organic matter presence in them, are created many problems in most projects. Some of these problems are low bearing capacity, excessive settlement in foundations, swelling, etc. If the organic soils are available on project sites, it should be stabilized. This research describes a study on the effect of quicklime and hydrated lime on geotechnical properties of organic soils in Shahid Zare forest and efficiency of used method. The results show that the hydrated lime more effective than quicklime on the compaction properties of organic soils. The effect of quicklime in increasing of compressive strength is more than of hydrated lime. In this study optimum amount of quicklime and hydrated lime determined 5% and 7% respectively.

Infiltration of leachate produced by municipal solid waste into the ground water poses a serious environmental hazard due to its high content of hydrocarbons and heavy metals. The leachate is the primary source of soil and water pollution.With respect to the climate, Iran is a relatively dry region with low sources of fresh water. Preservation of invaluable fresh water resources calls for serious research into the sources of water pollution in the region. Each day about, 500 ton wastes are produced in the Hamedan city and have been disposed in a site with lack of appropriate engineering conditions. The main aim of this research is to assess the effect of the Hamedan landfill environmental effects on groundwater resources with respect to heavy metals contamination. In this regard, the samples of leachate have been selected from the winter and summer depots of the landfill leachate. Also, groundwater samples were collected from the 5 water wells and two springs in order to study possible impact of leachate percolation into the groundwater resources. The leachate and groundwater samples were chemically characterized using Inductively Coupled Plasma of Optical Emission Spectrometry (ICP-OES), flame photometer and titration methods. Measured parameters include pH, Electrical Conductivity (EC), Heavy metals from the leachate, groundwater and spring samples. In addition to heavy metals analysis, chemical analysis for major cations and anions were also carried out in the groundwater and springs. According to Iranian Institute of Standard and Industrial Research and Iranian Environmental Protection Organization standards for drinking water and waste water, the results showed that all samples were contaminated, respectively. Furthermore it was found that, geological and hydrogeological conditions of site have a main role in distribution of contamination. Subsurface groundwater samples are contaminated more than other groundwater samples.