توصيفگر ها :
گروه شمع پيچي , بهسازي , اجزاء محدود , راديه , مكانيزم انتقال بار , ظرفيت باربري
چكيده فارسي :
ﻧﺪاﺳﯿﻮن ﻫﺎ اﻟﻤﺎﻧﯽ واﺳﻂ ﻣﯿﺎن ﺳﺎزه و ﺧﺎك ﻫﺴﺘﻨﺪ ﮐﻪ وﻇﯿﻔﻪ اﻧﺘﻘﺎل ﺑﺎر را دارا ﻫﺴﺘﻨﺪ. ﺣﺎل ﺑﺎﺗﻮﺟﻪ ﺑﻪ ﻇﺮﻓﯿﺖ ﺑﺎرﺑﺮي و ﻣﯿﺰان ﻧﯿﺮو، اﯾﻦ اﻟﻤﺎن واﺳﻂ دﭼﺎر ﺗﻐﯿﯿﺮات ﺧﻮاﻫﺪ ﺷﺪ، ﺑﻪ ﮔﻮﻧﻪ اي ﮐﻪ اﮔﺮ ﻣﻘﺪار ﻧﯿﺮو و ﻇﺮﻓﯿﺖ ﺑﺎرﺑﺮي ﺧﺎك از ﺣﺪ ﻣﻌﯿﻨﯽ ﮐﻤﺘﺮ ﺑﺎﺷﺪ، ﺑﻬﺘﺮﯾﻦ ﮔﺰﯾﻨﻪ ﻓﻮﻧﺪاﺳﯿﻮن ﻋﻤﯿﻖ ﯾﺎ ﺷﻤﻊ ﻫﺎ ﻫﺴﺘﻨﺪ. ﯾﮑﯽ از اﻧﻮاع ﺧﺎك ﮐﻪ ﺑﻪ ﻧﺴﺒﺖ دﯾﮕﺮ اﻧﻮاع ﺧﺎك، از ﻇﺮﻓﯿﺖ ﺑﺎرﺑﺮي ﮐﻤﺘﺮي ﺑﺮﺧﻮردار ﻫﺴﺘﻨﺪ، ﺧﺎكﻫﺎي رﺳﯽ ﻧﺮم ﻫﺴﺘﻨﺪ. ﻓﻮﻧﺪاﺳﯿﻮن ﻋﻤﯿﻖ اﻏﻠﺐ ﺑﺮاي ﺳﺎﺧﺖوﺳﺎز در ﭘﺮوژه ﻫﺎي ﻋﻤﺮاﻧﯽ و ﺗﺠﺎري و ﺳﺎزهﻫﺎي ﻋﻈﯿﻢ اﺳﺘﻔﺎده ﻣﯽﺷﻮﻧﺪ. ﺑﺎ اﯾﻦﺣﺎل ﺳﺎﺧﺖ ﻓﻮﻧﺪاﺳﯿﻮن ﻋﻤﯿﻖ ﺑﺮ روي زﻣﯿﻦ ﻫﺎي ﻧﺮم ﺑﻪ دﻟﯿﻞ وﯾﮋﮔﯽ ﻫﺎي ﻧﺎﻣﻄﻠﻮب ﻣﺎﻧﻨﺪ ﻧﺎﭘﺎﯾﺪاري، ﻇﺮﻓﯿﺖ ﺑﺎرﺑﺮي ﭘﺎﯾﯿﻦ و ﻧﺸﺴﺖﭘﺬﯾﺮي ﺑﺎﻻ در ﻣﺪت زﻣﺎن ﺑﻬﺮهﺑﺮداري، ﯾﮏ ﮐﺎر ﭼﺎﻟﺶ ﺑﺮاﻧﮕﯿﺰ اﺳﺖ. اﯾﻦ ﻣﺸﮑﻼت در ﺑﻠﻨﺪﻣﺪت ﻫﺰﯾﻨﻪ ﻫﺎي ﺗﻌﻤﯿﺮ و ﻧﮕﻬﺪاري ﺑﺎﻻ و ﺗﺄﺧﯿﺮ در زﻣﺎن ﺳﺎﺧﺖ را ﺑﻪ دﻧﺒﺎل ﺧﻮاﻫﺪ داﺷﺖ. روشﻫﺎي ﻣﺮﺳﻮم ﺑﻬﺴﺎزي زﻣﯿﻦ ﺑﻪ دﻟﯿﻞ اﯾﻦﮐﻪ ﭘﺮوژه ﺑﺎﯾﺪ در ﻣﺪت زﻣﺎن ﮐﻮﺗﺎﻫﯽ ﺗﮑﻤﯿﻞ ﺷﻮد از ﻟﺤﺎظ زﻣﺎﻧﯽ ﻣﻨﺎﺳﺐ ﻧﻤﯽ ﺑﺎﺷﻨﺪ. در اﯾﻦ ﺷﺮاﯾﻂ اﺳﺘﻔﺎده از رادﯾﻪ ﺷﻤﻊ ﺑﻪ دﻟﯿﻞ زﻣﺎن ﺳﺎﺧﺖ ﮐﻮﺗﺎه ﺗﺮ و ﮐﻨﺘﺮل ﻧﺸﺴﺖ ﺑﻬﺘﺮ ﻧﺴﺒﺖ ﺑﻪ ﺳﺎﯾﺮ روش ﻫﺎي ﺑﻬﺴﺎزي ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﻣﯽ ﮔﯿﺮﻧﺪ. اﻧﻮاع ﻣﺨﺘﻠﻔﯽ از ﺷﻤﻊ ﻫﺎي ﺑﺘﻨﯽ، ﭼﻮﺑﯽ، ﻓﻮﻻدي ﺑﺎ ﻣﻘﺎﻃﻊ ﻫﻨﺪﺳﯽ ﻣﺘﻔﺎوت ﺑﻪﻣﻨﻈﻮر اﺳﺘﻔﺎده در ﮔﺮوهﺷﻤﻊ ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﯾﮑﯽ از اﻧﻮاع ﺷﻤﻊ ﻫﺎ، ﺷﻤﻊ ﻫﺎي ﭘﯿﭽﯽ اﺳﺖ. ﺷﻤﻊ ﻫﺎي ﭘﯿﭽﯽ ﻣﺰاﯾﺎي ﻣﺨﺘﻠﻔﯽ ﻧﺴﺒﺖ ﺑﻪ ﺷﻤﻊ ﻫﺎي ﻣﻌﻤﻮل دارﻧﺪ، ﮐﻪ در آن ﻋﺒﺎرت " ﺷﻤﻊ ﻣﻌﻤﻮل " ﺑﻪ ﺷﻤﻊ ﻫﺎي ﺑﺎ ﺳﻄﺢ ﻣﻘﻄﻊ ﺛﺎﺑﺖ اﺷﺎره دارد. اﯾﻦ ﻣﺰاﯾﺎ ﻋﺒﺎرﺗﻨﺪ از: ﻇﺮﻓﯿﺖ ﻣﺤﻮري ﺑﺎﻻ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻗﻄﺮ ﻣﺘﻌﺎرف ﻣﯿﻠﻪ ﻣﻌﺎدل، وزن ﺳﺒﮏ و ﺗﺠﻬﯿﺰات ﻧﺼﺐ ﻣﺘﺤﺮك، ﺣﺪاﻗﻞ آﺷﻔﺘﮕﯽ ﺧﺎك ﻧﺎﺷﯽ از ﻧﺼﺐ ﺷﻤﻊ، زﻣﺎن ﻧﺼﺐ ﺳﺮﯾﻊ، ﺻﺪاي ﮐﻢ و ارﺗﻌﺎش در ﻃﻮل ﻧﺼﺐ، ﻗﺎﺑﻠﯿﺖ اﺳﺘﻔﺎده ﻣﺠﺪد ﺷﻤﻊ و ﻫﻤﭽﻨﯿﻦ ﻫﻨﮕﺎم ﻣﻮاﺟﻪ ﺑﺎ ﺗﺮاز ﺑﺎﻻي آب زﯾﺮزﻣﯿﻨﯽ اﺳﺖ. ﻋﻼوه ﺑﺮ اﯾﻦ، ﻣﻘﺎوﻣﺖ ﺑﺮﮐﻨﺶ ﺑﺎﻻي اﯾﻦ ﻧﻮع ﺷﻤﻊ، آن را ﺑﻪ ﯾﮏ ﮔﺰﯾﻨﻪ ﺑﻨﯿﺎدي ﻋﺎﻟﯽ ﺑﺮاي ﺳﺎزه ﻫﺎي ﺳﺒﮏ وزن ﺗﺒﺪﯾﻞ ﻣﯽ ﮐﻨﺪ ﮐﻪ ﻣﺴﺘﻌﺪ ﯾﺦ زدﮔﯽ ﯾﺎ ﺧﺎكﻫﺎي اﻧﺒﺴﺎﻃﯽ ﻫﺴﺘﻨﺪ. ﺷﻤﻊ ﻫﺎي ﭘﯿﭽﯽ ﻣﻌﻤﻮﻻ ﮔﺮوﻫﯽ ﻧﺼﺐ ﻣﯽ ﺷﻮﻧﺪ، ﮐﻪ در آن ﮔﺮوه ﺷﻤﻊ ﻫﺎ ﺑﻪ ﻋﻨﻮان ﻣﺠﻤﻮﻋﻪ اي از ﺷﻤﻊﻫﺎي داراي ﻓﺎﺻﻠﻪ ﻧﺰدﯾﮏ و ﻣﺘﺼﻞ ﺑﻪ ﺳﻄﺢ ﺑﺎ ﮐﻼﻫﮏ ﺷﻤﻊ ﺗﻌﺮﯾﻒ ﻣﯽ ﺷﻮﻧﺪ. اﮔﺮﭼﻪ ﻣﻄﺎﻟﻌﺎت ﮔﻮﻧﺎﮔﻮﻧﯽ ﺑﺮ ﮔﺮوه ﺷﻤﻊ ﭘﯿﭽﯽ اﻧﺠﺎم ﺷﺪه اﺳﺖ وﻟﯽ رﻓﺘﺎر دﻗﯿﻖ اﯾﻦ ﻧﻮع ﻓﻮﻧﺪاﺳﯿﻮن درك ﻧﺸﺪه اﺳﺖ. ﻫﺪف در اﯾﻦ ﭘﺎﯾﺎنﻧﺎﻣﻪ ﺑﺮرﺳﯽ و ﺷﻨﺎﺧﺖ رﻓﺘﺎر ﮔﺮوهﺷﻤﻊ ﭘﯿﭽﯽ اﺳﺖ ﮐﻪ ﺑﻪ ﻫﻤﯿﻦ ﻣﻨﻈﻮر ﯾﮏ ﻣﻄﺎﻟﻌﻪ ﻋﺪدي ﺳﻪ ﺑﻌﺪي ﺑﺎ اﺳﺘﻔﺎده از ﻧﺮماﻓﺰار ﭘﻠﮑﺴﯿﺲ ﺳﻪﺑﻌﺪي ﺗﻮﺳﻌﻪ داده ﺷﺪ. ﺻﺤﺖﺳﻨﺠﯽ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﮔﺰارش ﻫﺎي ﻣﯿﺪاﻧﯽ و آزﻣﺎﯾﺸﮕﺎﻫﯽ ﮔﺰارش ﺷﺪه ﺗﻮﺳﻂ دﯾﮕﺮ ﻣﺤﻘﻘﺎن اﻧﺠﺎم ﺷﺪ و در اداﻣﻪ ﻣﺪلﻫﺎي ﻋﺪدي ﺳﻪﺑﻌﺪي ﺑﻪ ﻣﻨﻈﻮر ﺑﺮرﺳﯽ اﺛﺮات ﻫﻨﺪﺳﻪ ﮐﻼﻫﮏ ﺳﺮﺷﻤﻊ ﻫﺎ، ﻓﺎﺻﻠﻪ ﮔﺮوه ﺷﻤﻊ، ﻧﻮع ﭼﯿﻨﺶ و ﭼﯿﺪﻣﺎن ﮔﺮوهﺷﻤﻊ ﺗﻮﺳﻌﻪ داده ﺷﺪ . ﺑﻨﺎﺑﺮاﯾﻦ ﺟﻬﺖ ﻣﻘﺎﯾﺴﻪ ﻫﺮ ﭼﻪ ﺑﻬﺘﺮ ﻋﻤﻠﮑﺮد ﮔﺮوهﺷﻤﻊ در ﺧﺎك رﺳﯽ ﻧﺮم، ﺗﻤﺎﻣﯽ ﭘﺎراﻣﺘﺮﻫﺎ در ﺧﺎك رﺳﯽ ﺳﺨﺖ ﻧﯿﺰ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻗﺮار ﮔﺮﻓﺖ. در اﯾﻦ ﭘﮋوﻫﺶ ﻋﺪدي ﯾﮏ ﮔﺮوهﺷﻤﻊ ﭘﯿﭽﯽ 9 ﻋﺪدي دو ﭘﺮهاي و دو ﻣﺪل ﮔﺮوهﺷﻤﻊ ﭘﯿﭽﯽ 5 ﻋﺪدي دو ﭘﺮهاي ﺑﺎ ﭼﯿﻨﺶ ﻣﺨﺘﻠﻒ ﺳﺎﺧﺘﻪ ﺷﺪ و ﺟﻬﺖ ﻣﻘﺎﯾﺴﻪ ﻫﺮﭼﻪ ﺑﻬﺘﺮ ﻧﺸﺴﺖ ﺗﻔﺎﺿﻠﯽ ﺳﯿﺴﺘﻢ، رادﯾﻪﻫﺎﯾﯽ ﺑﺎ ﺿﺨﺎﻣﺖﻫﺎي 0/3 و 0/7 ﻣﺘﺮي ﻣﺪل ﺳﺎزي ﮔﺮدﯾﺪ. ﻃﺒﻖ ﻧﺘﺎﯾﺞ ﻣﺪل ﺳﺎزي ﻋﺪدي، در ﺧﺎك رﺳﯽ ﻧﺮم زﻣﺎﻧﯽ ﮐﻪ ﺿﺨﺎﻣﺖ از 0/3 ﻣﺘﺮ ﺑﻪ 0/7 ﻣﺘﺮ ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ، ﻣﯿﺎﻧﮕﯿﻦ ﻋﻤﻠﮑﺮد ﻧﺸﺴﺖ ﺗﻔﺎﺿﻠﯽ ﺳﯿﺴﺘﻢ، ﺑﺎﻟﻎ ﺑﺮ 5 ﺑﺮاﺑﺮ و در ﺧﺎك رﺳﯽ ﺳﺨﺖ 3/5 ﺑﺮاﺑﺮ ﺑﻬﺒﻮد ﻣﯽﯾﺎﺑﺪ و رﻓﺘﺎر ﺳﺎزه از ﺣﺎﻟﺖ ﻧﺮم)اﻧﻌﻄﺎف ﭘﺬﯾﺮ( ﺑﻪ ﺳﻤﺖ رﻓﺘﺎر ﺻﻠﺐﺗﺮ)ﺧﻄﯽﺗﺮ( ﮔﺮاﯾﺶ ﭘﯿﺪا ﮐﺮد. ﻫﻤﭽﻨﯿﻦ ﺑﻬﯿﻨﻪ ﺗﺮﯾﻦ ﻓﺎﺻﻠﻪ ﮔﺮوهﺷﻤﻊ در دو ﻧﻮع ﺧﺎك رﺳﯽ ﻧﺮم و ﺳﺨﺖ ﺑﺮرﺳﯽ ﮔﺮدﯾﺪ. از ﻃﺮﻓﯽ در ﮔﺮوه ﺷﻤﻊ ﭘﯿﭽﯽ 5 ﻋﺪدي، ﺑﻬﺘﺮﯾﻦ ﻧﻮع ﭼﯿﺪﻣﺎن ﻫﻢ از ﻟﺤﺎظ ﺑﺎرﺑﺮي و ﻫﻢ از ﻟﺤﺎظ ﻧﺸﺴﺖ ﻣﺸﺨﺺ ﺷﺪ. در ﻧﻬﺎﯾﺖ ﻧﻮع ﮔﺴﯿﺨﺘﮕﯽ ﺳﯿﺴﺘﻢ، ﻣﮑﺎﻧﯿﺮم اﻧﺘﻘﺎل ﺑﺎر و ﻓﺎﺻﻠﻪ ﺑﯿﻦ ﭘﺮهﻫﺎ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ.
چكيده انگليسي :
Foundations are elements of the interface between the structure and the soil, which have the task of transferring the load. Now, according to the carrying capacity and the amount of force, this interface element will undergo changes, so that if the amount of force and carrying capacity of the soil is less than a certain limit, the best option is deep foundation or piles. Soft clay soils are one of the types of soil that have less bearing capacity than other types of soil. Deep foundations are often used for construction in civil and commercial projects and massive structures. However, the construction of deep foundations on soft soils is a challenging task due to unfavorable characteristics such as instability, low bearing capacity, and high settlement during operation. These problems will lead to high maintenance costs and delays in construction in the long run. Conventional land improvement methods are not suitable in terms of time because the project must be completed in a short period of time. In this situation, the use of pile radius is used because of shorter construction time and better settlement control than other improvement methods. Different types of concrete, wooden, steel piles with different geometric sections have been used for use in the pile group. One of the types of candles is screw candles. Screw plugs have several advantages over conventional plugs, where the term "conventional plug" refers to plugs with a constant cross-section. These advantages include: high axial capacity in comparison with the conventional diameter of the equivalent rod, light weight and mobile installation equipment, minimum soil disturbance caused by pile installation, quick installation time, low noise and vibration during installation, the ability to reuse the pile and also when It faces the high level of underground water. In addition, the high shear strength of this type of pile makes it an excellent foundation choice for lightweight structures that are prone to freezing or expansive soils. Screw plugs are usually installed in a group, where a group of plugs is defined as a set of closely spaced plugs connected to the surface with a plug cap. Although various studies have been done on screw piles, the exact behavior of this type of foundation is not understood. The aim of this thesis is to investigate and understand the behavior of the screw plug group, for this purpose a 3D numerical study was developed using PLAXIS 3D software. Validation was done according to the field and laboratory reports reported by other researchers, and then three-dimensional numerical models were developed to investigate the effects of the candle cap geometry, the candle group distance, the type of arrangement and arrangement of the candle group. Therefore, in order to better compare the performance of the candle group in soft clay soil, all parameters were also studied in hard clay soil. In this numerical research, a 9-number two-blade screw plug group and two models of 5-number two-blade screw plug groups with different layouts were made, and in order to better compare the differential settlement of the system, radii with thicknesses of 0.3 and 0.7 meters were modeled. According to the numerical modeling results, in soft clay soil when the thickness changes from 0.3 m to 0.7 m, the average differential settlement performance of the system improves by more than 5 times and in hard clay soil by 3.5 times, and the behavior of the structure from a soft (flexible) state, it tended to a more rigid (more linear) behavior. Also, the optimal distance of the candle group was investigated in two types of soft and hard clay soil. On the other hand, in the group of 5 screw plugs, the best type of arrangement was determined both in terms of load and settlement. Finally, the type of system rupture, the load transfer mechanism and the distance between the vanes were investigated.
