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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Introduction
In regard to consumptions of oil materials by human, soil contamination causes worriness in environment and geotechnics areas in previous years, such that studying of soils lead to soil refine, soil bearing capacity and soil changing by infiltration of contamination. The rates of problems on environment are different and it depends on soil types and its structure, organic materials values, soil permeability, climate and type of contamination. In viewpoint of geotechnics, many investigations have been done on various contaminated soils that their result leads to optimum application of those as road construction and decrease of costs. In this research, with adding of different percentages of gasoil into the soil, engineering properties of contaminated soils were investigated and its effect on the erodibility of soils was studied. Regarding to the Hamedan oil storages complex extension and lateral installations, the study of contaminated soils are essential. Also, because the location of that complex is at urban area, the environmental risk of leaking of oil materials is available. Thus, the goal of this research is to investigate the erodibility of contaminated soils at the studied area.     
Material and methods
Hamedan oil storages complex is located about 17.7 km far from Hamedan city. In order to study engineering geological properties and erodibility of three layers of soils in studied area, the soil samplings were done from three soil layers. Based on the field and laboratory results, all of three soil layers were classified into SM class and had too much lime (Table 1). Testing program is divided into engineering geological tests and erodibility tests. All of the engineering geological tests on the uncontaminated and contaminated soils were undertaken according to ASTM (2000) (Table 2). In order to prepare the contaminated soils and to determine the maximum absorbable gasoil, the soil samples were contaminated by gasoil and some standard compaction tests were undertaken on the soils. According to the test results, upper and lower layers were saturated by 19% of gasoil and middle layer was saturated by 15% of gasoil. After determination of gasoil saturations percentages for studied soil layers, the 7, 13 and 19 percentages of gasoil were added into the upper and lower layers and the 5, 10 and 15 percentages of gasoil were added into the middle layer. Thus, for engineering geological tests, 9 samples of contaminated soils were prepared.   
Table 1. Soil properties of studied area

Lime percentage	Soil type	PI%	PL%	LL%	Sample	Layer
85.15	SM	8.99	40.65	49.64	L1	Upper
62.16	SM	15.49	32.12	47.61	L2	Middle
88.72	SM	15.46	27.14	42.60	L3	Lower

Table 2. Engineering geological tests according to ASTM (2000)

Standard No.	Test type
ASTM-D422 (2000)	Soil classification
ASTM-D4318-87 (2000)	Atterberg limits
ASTM-D698 (2000)	Standard Compaction
ASTM-D3080 (2000)	ِDirect shear
ASTM-D2166-87 (2000)	Uniaxial Compressive Strength

To prepare the sample for direct shear test, a mould with dimension of 10 cm *10 cm *2 cm was used. Then, the prepared sample was set inside the shear box and vertical stress was applied. All of direct shear tests were done in unconsolidated-undrained condition (UU), in maximum dry unit weight _dmax) and in optimum water content _{( opt})of soil samples.
All of the soil samples for uniaxial compressive strength tests were prepared in maximum dry unit weight and optimum water content. To prepare the soil samples, a split tube mould with 5*10 cm of dimensions was used. Based on that test, the soil samples are set under axial load and failure occurred at the end of the test.
To investigate the effect of gasoil on soil erodibility, first the erodibility tests by using rainfall simulator were done on uncontaminated soils and then, on contaminated soil with different percentages of gasoil. All of soil samples for erodibility test were prepared into the pans with 30*30*15 cm of dimensions and in maximum dry unit weight and optimum water content. The thickness of soil samples were 5 cm and the gravelly drainage layers were 10 cm. The rainfall intensity was equal to rainfall intensity of sampling area (29 mm/hours) and the steepness of soil samples were equals to sampling area steepness (10 to 40 degrees). After catching of runoff and drained water, the eroded soils were weighted and the weight loss of soil samples was calculated.   
Results and discussion
All of the engineering geological tests results are shown in Table 3. With increasing of the gasoil percentages, dry maximum unit weights of all three layers have decrease trends while the optimum water contents have increase trends. Surrounding of the soil grains by gasoil and water causes the easy sliding of grains and more compaction. The Atterberg test results shows that liquid and plasticity limits of soil had increase trend with increasing the gasoil. In the middle layer its trend is more than the others. Because the viscosity of gasoil is more than the water viscosity, the adhesion of contaminated soil would be more than the uncontaminated soil and then, the liquid and plasticity limits of contaminated soils are more than the others. The uniaxial compressive strength results show that the undrained strength of contaminated soils would be decrease with increasing the gasoil content. This behavior is the result of sliding of the contaminated soil grains on each other.
The results of erodibility tests results are shown in Table 4. The erodibility would be increase with increasing the gasoil percentages. Also, it would be increase with steepness dips degrees. In compare to the uncontaminated soils, the maximum weight loss of the contaminated soil is 608.3 kg/m².hr in 15% of gasoil and 40 degrees of steepness in L2 layer. The minimum weight loss of the contaminated soil is 13.33 kg/m².hr in 0% of gasoil and 10 degrees of steepness in L3 layer. Thus, the assessment of gasoil effect on erodibility of soils is very important.
Table 3. Results of the engineering geological tests on the uncontaminated and contaminated soil samples

Layers	Gasoil percentage	Liquid limit (%)	Plasticity limit (%)	Plasticity Index (%)	Maximum  dry unit  weight  (g/cm3)	Optimum water content (%)	Internal friction angle (ɸ)	Cohesion (kPa)	Uniaxial compressive strength (kPa)
L1	0%	49.64	40.65	8.99	1.65	22	4.6	7.4	18.4
	7%	54	40.13	13.87	1.87	10.5	4.04	6.6	8.7
	13%	55.67	43.71	11.95	1.88	8.5	3.26	3.7	7.8
	19%	55	40.65	14.34	1.96	3	2.3	2.75	3.5
L2	0%	47.61	32.12	15.49	1.87	14	6.97	6	9.6
	5%	64	40.39	23.61	2.08	9	5.73	5.5	7
	10%	66	46.63	19.37	2.11	6	5.15	4	6.1
	15%	68	49.09	18.91	2.14	3.5	4	2	1.25
L3	0%	42.6	27.14	15.46	1.62	22.3	2.6	10.7	22.6
	7%	56	39.27	16.72	1.92	9.5	2.41	8.5	10.5
	13%	57.18	41.66	15.51	2.01	6	2.17	7/3	7.8
	19%	63	42	20.99	2.03	3	1.45	6.9	4.4

 
Table 4. Results of the uncontaminated and contaminated soils in different steepness*

Layer	Gasoil percentage	Dip of 10◦	Dip of 20◦	Dip of 30◦	Dip of 40◦
L1	0%	56.4	70.4	73.2	111.06
	7%	149.6	178.8	248.4	202.53
	13%	166.53	227.2	241.6	278.93
	19%	227.86	256.66	419.86	334.66
L2	0%	30.8	102.53	156.53	317.73
	5%	58.66	142.66	151.2	324.8
	10%	74.93	168.66	244.53	365.73
	15%	105.73	283.73	359.86	608.13
L3	0%	13.33	75.06	79.46	86.26
	7%	55.2	98.53	78.13	81.06
	13%	124.13	176.8	145.73	140.06
	19%	196.4	279.46	200.93	210

Conclusion
1. According to the grain size analysis test results, all of three layers of soils around the Hamedan oil storage are SM with too much lime.
2. With increasing the gasoil, liquid and plasticity limits of three soil layers had increase trend. its trend in the middle layer is more than the others.
3. According to the erodibility results of contaminated soils, the weight loss of middle layer was more than the other layers because of the middle soil layer had lower percentages of lime.   
4. The gasoil causes decrease of soil strength and increase of weight losing. Thus, the uniaxial compressive strength and weight losing have reverse correlation.  
5. With increasing of the contamination, the cohesion and internal friction angle of soils would be decrease and then, the erodibility would be increase.
6. Maximum of erosion of contaminated soils was in 15 and 19 percentages of gasoil and it was three times more than that of uncontaminated soils.
7. The critical steepness of uncontaminated soil layers was 40 degrees for all three layers, but it was different for contaminated soils, 
8. Regarding to the location of Hamedan oil storages, the environmental risk of oil leakages and erodibility of contaminated soils are certain.  
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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