بررسي و مقايسه خصوصيات فيزيكي خاك هاي مارني حوزه درياچه قم با دو سازند مادري مختلف

Investigation and comparison of physical properties of marl soils in Qom Lake basin with two different maternal formations

فرسايش ﭘﺬﯾﺮي، ﻣﻘﺎوﻣﺖ و رﻓﺘﺎر ﻣﻬﻨﺪﺳﯽ ﺧﺎك ﻫﺎ، ﻣﺘﺎﺛﺮ از ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ و ﺷﯿﻤﯿﺎﯾﯽ آنﻫﺎ ﻣﯽ ﺑﺎﺷﺪ. ﻟﯿﺘﻮﻟﻮژي و ﺧﺼﻮﺻﯿﺎت ﺳﻨﮓ ﻣﺎدر ﻣﯽ ﺗﻮاﻧﺪ از ﻋﻮاﻣﻞ ﺗﺎﺛﯿﺮ ﮔﺬار و ﮐﻨﺘﺮلﮐﻨﻨﺪه ﺧﺼﻮﺻﯿﺎت و رﻓﺘﺎر ﺧﺎك ﻫﺎ ﺑﺎﺷﻨﺪ. اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺎ ﻫﺪف ﺑﺮرﺳﯽ و ﻣﻘﺎﯾﺴﻪ ﺑﺮﺧﯽ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ ﺧﺎك ﻫﺎي رﯾﺰداﻧﻪ ﻣﺎرﻧﯽ ﺑﺎ دو ﺳﺎزﻧﺪ ﻣﺎدري ﻣﺨﺘﻠﻒ در ﺣﻮﺿﻪ درﯾﺎﭼﻪ ﻧﻤﮏ ﻗﻢ ﺑﺎ ﺷﺮاﯾﻂ ﻣﺸﺎﺑﻪ اﻧﺠﺎم ﮔﺮﻓﺖ. ﻣﻄﺎﻟﻌﻪ ﺑﺮ روي 61 ﻧﻤﻮﻧﻪ ﮐﻪ از ﻋﻤﻖ 0/5 ﺗﺎ ﯾﮏ ﻣﺘﺮي و از ﺳﻪ ﻣﻨﻄﻘﻪ ﺣﻮﺿﻪ ﺑﺎ ﭘﺮاﮐﻨﺶ ﻣﻨﺎﺳﺐ در اﻃﺮاف ﺗﻬﺮان، ﻗﻢ و ﺳﺎوه ﺑﺮداﺷﺖ ﺷﺪه، اﻧﺠﺎم ﭘﺬﯾﺮﻓﺖ. ﻧﻤﻮﻧﻪ ﻫﺎ از ﺧﺎك ﻫﺎي ﻧﺰدﯾﮏ ﺑﻪ رﺧﻨﻤﻮن دو ﺳﺎزﻧﺪ ﻣﺎرﻧﯽ دوره ﻧﺌﻮژن، ﻗﺮﻣﺰ ﺑﺎﻻﯾﯽ و ﻗﻢ، ﺑﺮداﺷﺖ ﺷﺪه اﻧﺪ. ﭘﺎراﻣﺘﺮﻫﺎي ﻓﯿﺰﯾﮑﯽ ﻣﻮرد ﺑﺮرﺳﯽ ﻋﺒﺎرﺗﻨﺪ از ﭼﮕﺎﻟﯽ داﻧﻪ ﻫﺎي ﺧﺎك، داﻧﻪ ﺑﻨﺪي، ﺣﺪود اﺗﺮﺑﺮگ و ﻋﺪد ﻓﻌﺎﻟﯿﺖ ﺧﺎك ﮐﻪ ﻣﻄﺎﺑﻖ اﺳﺘﺎﻧﺪاردﻫﺎي ASTM ﺑﺮ روي ﻧﻤﻮﻧﻪ ﻫﺎ، اﻧﺪازه ﮔﯿﺮي و ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ﺑﺮرﺳﯽ ﺧﺼﻮﺻﯿﺎت ﻓﻮق ﻣﺸﺨﺺ ﮐﺮد ﮐﻪ ﺧﺎك ﻫﺎي ﺣﺎﺻﻞ از اﯾﻦ دو ﺳﺎزﻧﺪ ﻣﺎرﻧﯽ ﺑﯿﺸﺘﺮ ﺳﯿﻠﺘﯽ و ﺗﻤﺎﻣﺎَ در رده ﺧﺎك ﻫﺎي رﯾﺰداﻧﻪ ﺑﺎ ﺧﻤﯿﺮاﯾﯽ ﮐﻢ ﺗﺎ ﻣﺘﻮﺳﻂ ﻗﺮار ﻣﯽ ﮔﯿﺮﻧﺪ. ﻣﻘﺎدﯾﺮ ﻣﺮﺑﻮط ﺑﻪ ﻋﺪد ﻓﻌﺎﻟﯿﺖ ﺧﺎك و ﺣﺪود اﺗﺮﺑﺮگ ﺑﻪ-ﺧﺼﻮص ﺣﺪ ﺧﻤﯿﺮي و ﺷﺎﺧﺺ ﺧﻤﯿﺮي، دﻻﻟﺖ ﺑﺮ اﯾﻦ دارﻧﺪ ﮐﻪ ﮐﺎﻧﯽ ﻫﺎي رﺳﯽ در اﯾﻦ ﺧﺎك ﻫﺎ ﺑﻪ اﺣﺘﻤﺎل زﯾﺎد ﺑﯿﺸﺘﺮ از ﻧﻮع ﮐﺎﺋﻮﻟﯿﻨﯿﺖ و اﯾﻠﯿﺖ و ﮐﻤﺘﺮ از ﻧﻮع ﻣﻮﻧﺖ ﻣﻮرﯾﻠﻮﻧﯿﺖ ﻫﺴﺘﻨﺪ. ﻣﻘﺎﯾﺴﻪ ﻣﯿﺎﻧﮕﯿﻦ و ﺗﺠﺰﯾﻪ وارﯾﺎﻧﺲ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ دو ﮔﺮوه ﺧﺎك ﻣﺎرﻧﯽ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺑﺎ اﺳﺘﻔﺎده از آزﻣﻮن t، ﻣﺸﺨﺺ ﮐﺮد ﮐﻪ در ﺑﯿﺸﺘﺮ ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ، داراي اﺧﺘﻼف ﻣﻌﻨﯽ داري در ﺳﻄﺢ اﻃﻤﯿﻨﺎن ﺑﯿﺶ از 95 درﺻﺪ ﻫﺴﺘﻨﺪ. داﻧﻪ ﺑﻨﺪي، ﺣﺪ رواﻧﯽ، ﺷﺎﺧﺺ ﺧﻤﯿﺮي و ﻋﺪد ﻓﻌﺎﻟﯿﺖ ﺧﺎك، ﺧﺼﻮﺻﯿﺎت ﻓﯿﺰﯾﮑﯽ داراي اﺧﺘﻼف در اﯾﻦ دو ﮔﺮوه ﺧﺎك ﻫﺴﺘﻨﺪ. اﯾﻦ اﺧﺘﻼف ﺑﺎ ﺧﻮﺷﻪ ﺑﻨﺪي ﻧﻤﻮﻧﻪ ﻫﺎ ﺑﺮاﺳﺎس ﭘﺎراﻣﺘﺮﻫﺎي داراي اﺧﺘﻼف ﺑﻪ روش ﺳﻠﺴﻠﻪ ﻣﺮاﺗﺒﯽ، ﻣﻮرد اﻋﺘﺒﺎر ﺳﻨﺠﯽ و ﺗﺎﯾﯿﺪ ﻗﺮار ﮔﺮﻓﺖ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺣﻮﺿﻪ واﺣﺪ و ﺷﺮاﯾﻂ ﻣﺸﺎﺑﻪ ﺗﻮﭘﻮﮔﺮاﻓﯽ و ﻣﺤﯿﻄﯽ در ﺗﺸﮑﯿﻞ و ﺗﮑﺎﻣﻞ اﯾﻦ دو ﮔﺮوه ﺧﺎك ﻣﺎرﻧﯽ، ﻧﺘﺎﯾﺞ اﯾﻦ ﺗﺤﻘﯿﻖ دﻻﻟﺖ ﺑﺮ ﺗﺎﺛﯿﺮ ﺷﺮاﯾﻂ و ﺧﺼﻮﺻﯿﺎت ﻣﺤﯿﻂ رﺳﻮﺑﯽ ﺳﻨﮓ ﻣﺎدر ﺑﺮ ﺧﺼﻮﺻﯿﺎت ﺧﺎك ﻫﺎ ﺑﻪ ﺧﺼﻮص در ﻣﺮاﺣﻞ اوﻟﯿﻪ ﺗﮑﺎﻣﻠﯽ آنﻫﺎ دارد

Erodibility, resistance and soil engineering behavior are affected by their physical and chemical properties. Lithology and characteristics of parent rock can be such factors that influence on soil properties and behavior. The aim of this study was to investigate and compare some of the physical properties of Marly fine grained soils with two different maternal formations in a unit basin (Qom salt lake). The study was carried out on 61 soil samples. The physical parameters studied are the specific weight of the unit volume of soil, the grain size, the Atterberg limits and the soil activity number, which was measured according to ASTM standards. The investigation of the above mentioned soil properties showed that the soils of these two marl formations are silty and all are classified in the category of fine-grained soils with low to moderate plasticity. The values of the soil activity number and the Atterberg limits, especially the plasticity limit and plasticity index, indicated that the clay minerals in these soils are more Kaolinite and Illite and less montmorillonite. The comparison of variance and mean of physical properties of two groups of soil by using t-student (two independent groups) test, showed that in most of the physical properties of two Marl Soil groups consist of liquid limit, plasticity index, soil activity number and percentage of clay, silt and sand, there is a differences significant level of confidence of over 95%. This difference of physical properties was validated by clustering the samples by hierarchical method. Considering to the unit basin and similar conditions in the formation and evolution of these two groups of soil, the results of this study indicate that conditions and characteristics of the sedimentary environment of the matter rocks mainly affected on the properties and behavior of soils, especially in their early stages of evolution.