fa بررسی تأثیر آلودگی ناشی از گازوئیل بر فرسایش‌پذیری خاک‌های غنی از آهک در حاشیه انبار نفت همدان با استفاده از دستگاه شبیه‌ساز باران زمین شناسی مهندسی Engineering Geology مقاله پژوهشی Original Research .<span style="font-family:b lotus;"><span style="font-size:10.0pt;">آلودگی خاک‌ها با هر کدام از فرآورده‌های نفتی باعث تغییر در ویژگی‌های زمین‌شناسی مهندسی خاک‌ها شده و رفتار خاک‌ها را تغییر می‌دهد. در این پژوهش به‌منظور بررسی تأثیر آلودگی ناشی از گازوییل بر فرسایش‌پذیری خاک‌ها، محدودۀ انبار نفت همدان انتخاب گردید و به این منظور از دستگاه شبیه‌ساز باران استفاده شد. براساس نتایج حاصل از بررسی‌های صحرایی و آزمایشگاهی، سه لایه خاک در محدودۀ بررسی شده وجود دارد که مطابق رده‌بندی یونیفاید در ردۀ </span></span><span dir="LTR"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">SM</span></span></span><span style="font-family:b lotus;"><span style="font-size:10.0pt;"> قرار دارند و دارای مقادیر بسیار بالای آهک، یعنی 15/85%&nbsp; در لایۀ بالایی، 16/62% در لایۀ میانی و 72/88% در لایۀ پایینی هستند. تعیین ویژگی‌های زمین‌شناسی مهندسی نمونه‌ها با انجام آزمایش‌های تعیین درصد رطوبت، دانه‌بندی و هیدرومتری، کلسی‌متری، تعیین </span></span><span dir="LTR"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">G_S</span></span></span><span style="font-family:b lotus;"><span style="font-size:10.0pt;">، حدود آتربرگ، تراکم استاندارد، برش مستقیم و مقاومت فشاری تک‌محوری روی نمونه‌های غیرآلوده و آلوده به گازوییل انجام شد. برای بررسی اثر ویژگی‌های زمین‌شناسی مهندسی نمونه‌های غیرآلوده و آلوده به گازوییل بر فرسایش‌پذیری با استفاده از دستگاه شبیه‌ساز باران، از شیب‌های 10، 20، 30 و 40 درجه، شدت بارش مشابه با میانگین شدت بارش منطقه و تراکم خاک با رطوبت بهینه استفاده شد. نتایج به‌دست آمده نشان می‌دهد که آلودگی ناشی از گازوییل باعث کاهش مقادیر پارامترهای مقاومتی خاک‌های منطقۀ بررسی شده و این کاهش مقادیر پارامترهای مقاومتی، خود باعث افزایش فرسایش‌پذیری خاک‌های آلوده نسبت به خاک‌های غیرآلوده شده است. بدین صورت که حداکثر مقدار فرسایش در سه لایۀ خاک در 19 و 15 درصد گازوییل تقریباً 3 برابر مقدار فرسایش در حالت غیرآلوده است.</span></span> <strong>Introduction</strong><br> 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.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br> <strong>Material</strong><strong> and methods</strong><br> 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.&nbsp;&nbsp;&nbsp;<br> <strong>Table 1. Soil properties of studied area</strong> <table align="center" border="1" cellpadding="0" cellspacing="0" dir="rtl"> <tbody> <tr> <td>Lime percentage</td> <td>Soil type</td> <td>PI%<span dir="RTL"></span></td> <td>PL%<span dir="RTL"></span></td> <td>LL%<span dir="RTL"></span></td> <td>Sample</td> <td>Layer</td> </tr> <tr> <td>85.15</td> <td>SM</td> <td>8.99</td> <td>40.65</td> <td>49.64</td> <td>L1</td> <td>Upper</td> </tr> <tr> <td>62.16</td> <td>SM<span dir="RTL"></span></td> <td>15.49</td> <td>32.12</td> <td>47.61</td> <td>L2</td> <td>Middle</td> </tr> <tr> <td>88.72</td> <td>SM</td> <td>15.46</td> <td>27.14</td> <td>42.60</td> <td>L3</td> <td>Lower</td> </tr> </tbody> </table> <div style="clear:both;"></div><strong>Table 2. Engineering geological tests according to ASTM</strong> <strong>(2000)</strong><strong><span dir="RTL"></span></strong> <table align="center" border="1" cellpadding="0" cellspacing="0" dir="rtl"> <tbody> <tr> <td style="height:22px;">Standard No.</td> <td style="height:22px;">Test type</td> </tr> <tr> <td style="height:23px;">ASTM-D422 (2000)<span dir="RTL"></span></td> <td style="height:23px;">Soil classification<span dir="RTL"></span></td> </tr> <tr> <td style="height:22px;">ASTM-D4318-87 (2000)<span dir="RTL"></span></td> <td style="height:22px;">Atterberg limits</td> </tr> <tr> <td style="height:23px;">ASTM-D698 (2000)<span dir="RTL"></span></td> <td style="height:23px;">Standard Compaction</td> </tr> <tr> <td style="height:22px;">ASTM-D3080 (2000)<span dir="RTL"></span></td> <td style="height:22px;"><span dir="RTL">ِ</span>Direct shear</td> </tr> <tr> <td style="height:23px;">ASTM-D2166-87 (2000)<span dir="RTL"></span></td> <td style="height:23px;">Uniaxial Compressive Strength</td> </tr> </tbody> </table> <div style="clear:both;"></div>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.<br> 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.<br> 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.&nbsp;&nbsp;&nbsp;<br> <strong>Results and discussion</strong><br> 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.<br> 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.<br> <strong>Table 3. Results of the engineering geological tests on the uncontaminated and contaminated soil samples</strong> <table border="1" cellpadding="0" cellspacing="0" style="width:100.0%;" width="100%"> <tbody> <tr> <td style="width:10.76%;height:84px;">Layers</td> <td style="width:8.64%;height:84px;">Gasoil percentage</td> <td style="width:9.54%;height:84px;">Liquid limit (%)</td> <td style="width:9.54%;height:84px;">Plasticity limit (%)</td> <td style="width:9.54%;height:84px;">Plasticity Index (%)</td> <td style="width:8.64%;height:84px;">Maximum&nbsp; dry unit&nbsp; weight&nbsp; (g/cm³)</td> <td style="width:8.64%;height:84px;">Optimum water content (%)</td> <td style="width:10.5%;height:84px;">Internal friction angle (<span dir="RTL">ɸ</span>)</td> <td style="width:8.44%;height:84px;">Cohesion (kPa)</td> <td style="width:15.76%;height:84px;">Uniaxial compressive strength (kPa)</td> </tr> <tr> <td rowspan="4" style="width:10.76%;height:20px;">L1</td> <td style="width:8.64%;height:20px;">0%</td> <td style="width:9.54%;height:20px;">49.64</td> <td style="width:9.54%;height:20px;">40.65</td> <td style="width:9.54%;height:20px;">8.99</td> <td style="width:8.64%;height:20px;">1.65</td> <td style="width:8.64%;height:20px;">22</td> <td style="width:10.5%;height:20px;">4.6</td> <td style="width:8.44%;height:20px;">7.4</td> <td style="width:15.76%;height:20px;">18.4</td> </tr> <tr> <td style="width:8.64%;">7%</td> <td style="width:9.54%;">54</td> <td style="width:9.54%;">40.13</td> <td style="width:9.54%;">13.87</td> <td style="width:8.64%;">1.87</td> <td style="width:8.64%;">10.5</td> <td style="width:10.5%;">4.04</td> <td style="width:8.44%;">6.6</td> <td style="width:15.76%;">8.7</td> </tr> <tr> <td style="width:8.64%;">13%</td> <td style="width:9.54%;">55.67</td> <td style="width:9.54%;">43.71</td> <td style="width:9.54%;">11.95</td> <td style="width:8.64%;">1.88</td> <td style="width:8.64%;">8.5</td> <td style="width:10.5%;">3.26</td> <td style="width:8.44%;">3.7</td> <td style="width:15.76%;">7.8</td> </tr> <tr> <td style="width:8.64%;">19%</td> <td style="width:9.54%;">55</td> <td style="width:9.54%;">40.65</td> <td style="width:9.54%;">14.34</td> <td style="width:8.64%;">1.96</td> <td style="width:8.64%;">3</td> <td style="width:10.5%;">2.3</td> <td style="width:8.44%;">2.75</td> <td style="width:15.76%;">3.5</td> </tr> <tr> <td rowspan="4" style="width:10.76%;height:9px;">L2</td> <td style="width:8.64%;height:9px;">0%</td> <td style="width:9.54%;height:9px;">47.61</td> <td style="width:9.54%;height:9px;">32.12</td> <td style="width:9.54%;height:9px;">15.49</td> <td style="width:8.64%;height:9px;">1.87</td> <td style="width:8.64%;height:9px;">14</td> <td style="width:10.5%;height:9px;">6.97</td> <td style="width:8.44%;height:9px;">6</td> <td style="width:15.76%;height:9px;">9.6</td> </tr> <tr> <td style="width:8.64%;">5%</td> <td style="width:9.54%;">64</td> <td style="width:9.54%;">40.39</td> <td style="width:9.54%;">23.61</td> <td style="width:8.64%;">2.08</td> <td style="width:8.64%;">9</td> <td style="width:10.5%;">5.73</td> <td style="width:8.44%;">5.5</td> <td style="width:15.76%;">7</td> </tr> <tr> <td style="width:8.64%;">10%</td> <td style="width:9.54%;">66</td> <td style="width:9.54%;">46.63</td> <td style="width:9.54%;">19.37</td> <td style="width:8.64%;">2.11</td> <td style="width:8.64%;">6</td> <td style="width:10.5%;">5.15</td> <td style="width:8.44%;">4</td> <td style="width:15.76%;">6.1</td> </tr> <tr> <td style="width:8.64%;">15%</td> <td style="width:9.54%;">68</td> <td style="width:9.54%;">49.09</td> <td style="width:9.54%;">18.91</td> <td style="width:8.64%;">2.14</td> <td style="width:8.64%;">3.5</td> <td style="width:10.5%;">4</td> <td style="width:8.44%;">2</td> <td style="width:15.76%;">1.25</td> </tr> <tr> <td rowspan="4" style="width:10.76%;">L3</td> <td style="width:8.64%;">0%</td> <td style="width:9.54%;">42.6</td> <td style="width:9.54%;">27.14</td> <td style="width:9.54%;">15.46</td> <td style="width:8.64%;">1.62</td> <td style="width:8.64%;">22.3</td> <td style="width:10.5%;">2.6</td> <td style="width:8.44%;">10.7</td> <td style="width:15.76%;">22.6</td> </tr> <tr> <td style="width:8.64%;">7%</td> <td style="width:9.54%;">56</td> <td style="width:9.54%;">39.27</td> <td style="width:9.54%;">16.72</td> <td style="width:8.64%;">1.92</td> <td style="width:8.64%;">9.5</td> <td style="width:10.5%;">2.41</td> <td style="width:8.44%;">8.5</td> <td style="width:15.76%;">10.5</td> </tr> <tr> <td style="width:8.64%;">13%</td> <td style="width:9.54%;">57.18</td> <td style="width:9.54%;">41.66</td> <td style="width:9.54%;">15.51</td> <td style="width:8.64%;">2.01</td> <td style="width:8.64%;">6</td> <td style="width:10.5%;">2.17</td> <td style="width:8.44%;">7/3</td> <td style="width:15.76%;">7.8</td> </tr> <tr> <td style="width:8.64%;">19%</td> <td style="width:9.54%;">63</td> <td style="width:9.54%;">42</td> <td style="width:9.54%;">20.99</td> <td style="width:8.64%;">2.03</td> <td style="width:8.64%;">3</td> <td style="width:10.5%;">1.45</td> <td style="width:8.44%;">6.9</td> <td style="width:15.76%;">4.4</td> </tr> </tbody> </table> &nbsp;<br> <strong>Table 4. Results of the uncontaminated and contaminated soils in different steepness*</strong> <table align="center" border="1" cellpadding="0" cellspacing="0"> <tbody> <tr> <td style="width:74px;">Layer</td> <td style="width:82px;">Gasoil percentage</td> <td style="width:76px;">Dip of 10◦</td> <td style="width:76px;">Dip of 20◦</td> <td style="width:76px;">Dip of 30◦</td> <td style="width:76px;">Dip of 40◦</td> </tr> <tr> <td rowspan="4" style="width:74px;">L1</td> <td style="width:82px;">0%</td> <td style="width:76px;">56.4</td> <td style="width:76px;">70.4</td> <td style="width:76px;">73.2</td> <td style="width:76px;">111.06</td> </tr> <tr> <td style="width:82px;">7%</td> <td style="width:76px;">149.6</td> <td style="width:76px;">178.8</td> <td style="width:76px;">248.4</td> <td style="width:76px;">202.53</td> </tr> <tr> <td style="width:82px;">13%</td> <td style="width:76px;">166.53</td> <td style="width:76px;">227.2</td> <td style="width:76px;">241.6</td> <td style="width:76px;">278.93</td> </tr> <tr> <td style="width:82px;">19%</td> <td style="width:76px;">227.86</td> <td style="width:76px;">256.66</td> <td style="width:76px;">419.86</td> <td style="width:76px;">334.66</td> </tr> <tr> <td rowspan="4" style="width:74px;">L2</td> <td style="width:82px;">0%</td> <td style="width:76px;">30.8</td> <td style="width:76px;">102.53</td> <td style="width:76px;">156.53</td> <td style="width:76px;">317.73</td> </tr> <tr> <td style="width:82px;">5%</td> <td style="width:76px;">58.66</td> <td style="width:76px;">142.66</td> <td style="width:76px;">151.2</td> <td style="width:76px;">324.8</td> </tr> <tr> <td style="width:82px;">10%</td> <td style="width:76px;">74.93</td> <td style="width:76px;">168.66</td> <td style="width:76px;">244.53</td> <td style="width:76px;">365.73</td> </tr> <tr> <td style="width:82px;">15%</td> <td style="width:76px;">105.73</td> <td style="width:76px;">283.73</td> <td style="width:76px;">359.86</td> <td style="width:76px;">608.13</td> </tr> <tr> <td rowspan="4" style="width:74px;">L3</td> <td style="width:82px;">0%</td> <td style="width:76px;">13.33</td> <td style="width:76px;">75.06</td> <td style="width:76px;">79.46</td> <td style="width:76px;">86.26</td> </tr> <tr> <td style="width:82px;">7%</td> <td style="width:76px;">55.2</td> <td style="width:76px;">98.53</td> <td style="width:76px;">78.13</td> <td style="width:76px;">81.06</td> </tr> <tr> <td style="width:82px;">13%</td> <td style="width:76px;">124.13</td> <td style="width:76px;">176.8</td> <td style="width:76px;">145.73</td> <td style="width:76px;">140.06</td> </tr> <tr> <td style="width:82px;">19%</td> <td style="width:76px;">196.4</td> <td style="width:76px;">279.46</td> <td style="width:76px;">200.93</td> <td style="width:76px;">210</td> </tr> </tbody> </table> <div style="clear:both;"></div><strong>Conclusion</strong><br> 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.<br> 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.<br> 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.&nbsp;&nbsp;&nbsp;<br> 4. The gasoil causes decrease of soil strength and increase of weight losing. Thus, the uniaxial compressive strength and weight losing have reverse correlation.&nbsp;&nbsp;<br> 5. With increasing of the contamination, the cohesion and internal friction angle of soils would be decrease and then, the erodibility would be increase.<br> 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.<br> 7. The critical steepness of uncontaminated soil layers was 40 degrees for all three layers, but it was different for contaminated soils,&nbsp;<br> 8. Regarding to the location of Hamedan oil storages, the environmental risk of oil leakages and erodibility of contaminated soils are certain.&nbsp;&nbsp;<br> <a href="./files/site1/files/132/5Extended_Abstracts.pdf">./files/site1/files/132/5Extended_Abstracts.pdf</a> آلودگی خاک, ویژگی‌های زمین‌شناسی مهندسی خاک, دستگاه شبیه‌ساز باران, فرسایش‌پذیری, انبار نفت, همدان Soil contamination, Engineering geological properties of soil, Rainfall simulator, Erodibility, Oil storage, Hamedan 289 316 http://jeg.khu.ac.ir/browse.php?a_code=A-10-222-2&slc_lang=fa&sid=1 Seyed Davoud Mohammadi سید داود محمدی 10031947532846003689 10031947532846003689 Yes دانشگاه بوعلی سینا، گروه زمین‌شناسی Elahe Hosseinabadi2 الهه حسین آبادی 10031947532846003690 10031947532846003690 No دانشگاه بوعلی سینا، گروه زمین‌شناسی