储油罐环形加筋防护墙变形特征及其影响因素
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摘要
储油罐环形加筋防护墙是由填土、筋体、格栅返包式面板组成的一个环形整体复合结构,具有明显的空间特性及其与储油罐之间复杂的相互作用,相关研究理论明显滞后于工程应用。由于环形加筋防护墙无法忽略其空间特性的影响,通过Plaxis 3D三维有限元软件进行数值模拟,采用小应变土体硬化模型作为加筋土体本构模型,研究储油罐环形加筋防护墙墙体的变形特征及加筋材料的受力特征,探讨墙体高度、厚度、墙面坡度及土工格栅刚度、加筋间距等因素对墙体变形特征的影响。结果表明:防护墙墙面侧位移随着防护墙高度、厚度和墙面倾斜角度的减小而减小,但墙体厚度过小和加筋间距过大将导致防护墙倾覆趋势增大,过小的土工格栅刚度会导致墙侧位移过大,因此需严格控制以上设计参数;加筋防护墙墙体的修筑将加大储油罐边缘处地基沉降,储油罐内燃油的装载状态不影响加筋防护墙地基沉降情况,但油罐地基最大沉降差随着储油罐内装载燃油的增多而减小;根据格栅最大拉应力位置所推测的加筋防护墙破坏面经过墙趾曲线,墙后土压力受墙面坡度影响巨大,设计时应根据坡度选择合适的设计方法。
The reinforced protecting wall is a composite structure located around the oil tank. It is consisted of three parts which are the backfill soil,reinforcements arranged in the soil and geogrid panels respectively. The reinforced protecting wall has received very few attentions of researchers. Related researches haven't taken the influence of spatial character on the reinforced protecting wall into consideration. As a result,its theoretical researches lag behind its engineering application currently. Due to the fact that the circular geosynthetics-reinforced protection walls cannot ignore the influence of its space characteristics,the numerical analysis is carried out withPlaxis3 D finite element software. The reinforced concrete protection wall and the reinforced concrete dome are simulated with the slab unit. The geotextiles are made of geosynthetics. In order to better simulate the actual working conditions,interface units are set up at the interfaces of soil,concrete and geotextiles. The tank body is simulated with the plate element,and the oil in the tank is simulated by the entity unit. Because the tank and internal fuel use entity modeling,the interaction between soil and superstructure can be considered,and the rationality and accuracy of numerical simulation can be improved. The deformation characteristics of circular geosynthetics-reinforced protection walls located around oil tank and mechanical characteristics of reinforced materials are investigated with developing a three-dimensional numerical model. The model uses the hardening soil model with small-stain stiffness( HSS models) as reinforced soil constitutive model. By changing geosynthetics-reinforced protection wall height,thickness,gradient of wall space,geogrid stiffness and reinforcement spacing,the effects of these factors on the wall deformation characteristics are explored. This paper conducts a detail study on the influence of the size of reinforced protecting wall on the serviceability limit state. The study is composed of deformation behavior,the foundation settlement,and the distribution of strains and tensile in the reinforcement. According to the above analysis,this paper puts forward some suggestions to optimize shape and size of reinforced protecting wall. The results show that the wall lateral displacement decreases with the decrease in the wall thickness,height and gradient of wall space. Also,too small wall thickness and too large reinforcement spacing can lead to the increase of the overturning trend of protection wall,and smaller stiffness of geogrid results in excessive lateral displacement of wall.Thus,these parameters should be taken into account in practice. The construction of reinforced wall can increase the settlement of foundation on the edge of storage tank. The loading state of the fuel in the storage tank does not affect the settlement of the reinforced protective wall foundation. However,the maximum settlement difference of the tank foundation decreases with the increase of fuel oil in the storage tank. Further,the potential failure surface of the geosynthetics-reinforced protection walls according to the position of maximum tensile stress of geogrid is a curve going through wall toe. The soil pressure behind the wall is greatly affected by the wall gradient. So the gradient should be considered when choosing a appropriate design method.
The reinforced protecting wall is a composite structure located around the oil tank. It is consisted of three parts which are the backfill soil,reinforcements arranged in the soil and geogrid panels respectively. The reinforced protecting wall has received very few attentions of researchers. Related researches haven't taken the influence of spatial character on the reinforced protecting wall into consideration. As a result,its theoretical researches lag behind its engineering application currently. Due to the fact that the circular geosynthetics-reinforced protection walls cannot ignore the influence of its space characteristics,the numerical analysis is carried out withPlaxis3 D finite element software. The reinforced concrete protection wall and the reinforced concrete dome are simulated with the slab unit. The geotextiles are made of geosynthetics. In order to better simulate the actual working conditions,interface units are set up at the interfaces of soil,concrete and geotextiles. The tank body is simulated with the plate element,and the oil in the tank is simulated by the entity unit. Because the tank and internal fuel use entity modeling,the interaction between soil and superstructure can be considered,and the rationality and accuracy of numerical simulation can be improved. The deformation characteristics of circular geosynthetics-reinforced protection walls located around oil tank and mechanical characteristics of reinforced materials are investigated with developing a three-dimensional numerical model. The model uses the hardening soil model with small-stain stiffness( HSS models) as reinforced soil constitutive model. By changing geosynthetics-reinforced protection wall height,thickness,gradient of wall space,geogrid stiffness and reinforcement spacing,the effects of these factors on the wall deformation characteristics are explored. This paper conducts a detail study on the influence of the size of reinforced protecting wall on the serviceability limit state. The study is composed of deformation behavior,the foundation settlement,and the distribution of strains and tensile in the reinforcement. According to the above analysis,this paper puts forward some suggestions to optimize shape and size of reinforced protecting wall. The results show that the wall lateral displacement decreases with the decrease in the wall thickness,height and gradient of wall space. Also,too small wall thickness and too large reinforcement spacing can lead to the increase of the overturning trend of protection wall,and smaller stiffness of geogrid results in excessive lateral displacement of wall.Thus,these parameters should be taken into account in practice. The construction of reinforced wall can increase the settlement of foundation on the edge of storage tank. The loading state of the fuel in the storage tank does not affect the settlement of the reinforced protective wall foundation. However,the maximum settlement difference of the tank foundation decreases with the increase of fuel oil in the storage tank. Further,the potential failure surface of the geosynthetics-reinforced protection walls according to the position of maximum tensile stress of geogrid is a curve going through wall toe. The soil pressure behind the wall is greatly affected by the wall gradient. So the gradient should be considered when choosing a appropriate design method.
引文
Abdelouhab A,Dias D,Freitag N.2011.Numerical analysis of the behaviour of mechanically stabilized earth walls reinforced with different types of strips[J].Geotextiles and Geomembranes,29(2):116-129.
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Bergado D T,Teerawattanasuk C.2008.2D and 3D numerical simulations of reinforced embankments on soft ground[J].Geotextiles and Geomembranes,26(1):39-55.
Blatz J A,Bathurst R J.2003.Limit equilibrium analysis of large-scale reinforced and unreinforced embankments loaded by a strip footing[J].Canadian Geotechnical Journal,40(6):1084-1092.
Chang S P,Zhang S M.2007.Manual of Engineering Geology[M].Beijing:China Architecture&Building Press:96-152.
China National Petroleum Corporation.2014.Code for design of vertical cylindrical welded steel oil tanks[S].Beijing:China Planning Press.
Fan Q Q,Zhang Z L,Jiang Y Q.2010.The present situation of overlying oil tank in China[J].China Storage&Transport,4:99-100.
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Ho S K,Rowe R K.1996.Effect of wall geometry on the behaviour of reinforced soil walls[J].Geotextiles and Geomembranes,14(10):521-541.
Huang B Q,Bathurst R J,Hatami K.2009.Numerical study of reinforced soil segmental walls using three different constitutive soil models[J].Journal of Geotechnical and Geoenvironmental Engineering,135(10):1486-1498.
Isabel M,Pinto M,Cousens T W.1996.Geotextile reinforced brick faced retaining walls[J].Geotextiles and Geomembranes,14(9):449-464.
Jie Y X,Bai Y L,Zheng B.2017.Study on critical slip surface of acceleration in slope stability analysis[J].Journal of Engineering Geology,25(5):1238-1244.
Mirmoradi S H,Ehrlich M.2014.Numerical evaluation of the behavior of GRS walls with segmental block facing under working stress conditions[J].Journal of Geotechnical and Geoenvironmental Engineering,141(3):4014109.
Mohamed S B A,Yang K H,Hung W Y.2014.Finite element analyses of two-tier geosynthetic-reinforced soil walls:Comparison involving centrifuge tests and limit equilibrium results[J].Computers and Geotechnics,61:67-84.
Rowe R K,Skinner G D.2001.Numerical analysis of geosynthetic reinforced retaining wall constructed on a layered soil foundation[J].Geotextiles and Geomembranes,19(7):387-412.
Shang Y H,Xu L R,Shang L,et al.2017.Effect of grid strength on pilesoil stress ratio of pile-net composite[J].Journal of Engineering Geology,25(1):95-101.
Wang R,Wang S,Peng D L.2016.Steel-plastic tenon geogrid and its interaction characteristics with backfills[J].Journal of Engineering Geology,24(3):391-397.
Yang K H,Zornberg J G,Liu C N,et al.2012.Stress distribution and development within geosynt-hetic-reinforced soil slopes[J].Geosynthetics International,19(1):62-78.
Yin Y P,Yan Y,Chen B,et al.2003.Deformation and failure of superhigh reinforced retaining wall and its remediation in wushan new town on the three-gorges reservoir[J].Journal of Engineering Geology,11(1):89-99.
Zhu D Y,Lee C F,Jiang H D.2003.Generalised framework of limit equilibrium methods for slope stability analysis[J].Géotechnique,53(4):377-395.
Zornberg J G.1996.Performance of geotextile-reinforced soil structures[J].University of California,Berkeley Dec,2769-2769.
常士骠,张苏民.2007.工程地质手册[M].北京:中国建筑工业出版社:96-152.
范乾权,张赞牢,姜玉泉.2010.国内覆土油罐现状探讨[J].中国储运,4:99-100.
介玉新,柏永亮,张彬.2017.边坡稳定分析中加速度临界滑动面研究[J].工程地质学报,25(5):1238-1244.
商拥辉,徐林荣,商丽,等.2017.格栅强度对桩-网复合地基桩-土应力比影响研究[J].工程地质学报,25(1):95-101.
王睿,王双,彭大雷.2016.钢塑凸榫土工格栅及其筋土界面特性研究[J].工程地质学报,24(3):391-397.
中国石油天然气集团公司.2014.立式圆筒形钢制焊接油罐设计规范[S].北京:中国计划出版社.
Auvinet G,Gonzalez J L.2000.Three-dimensional reliability analysis o earth slopes[J].Computers and Geotechnics,26(3):247-261.
Bergado D T,Teerawattanasuk C.2008.2D and 3D numerical simulations of reinforced embankments on soft ground[J].Geotextiles and Geomembranes,26(1):39-55.
Blatz J A,Bathurst R J.2003.Limit equilibrium analysis of large-scale reinforced and unreinforced embankments loaded by a strip footing[J].Canadian Geotechnical Journal,40(6):1084-1092.
Chang S P,Zhang S M.2007.Manual of Engineering Geology[M].Beijing:China Architecture&Building Press:96-152.
China National Petroleum Corporation.2014.Code for design of vertical cylindrical welded steel oil tanks[S].Beijing:China Planning Press.
Fan Q Q,Zhang Z L,Jiang Y Q.2010.The present situation of overlying oil tank in China[J].China Storage&Transport,4:99-100.
Herold A,Wolffersdorff P.2009.The use of hardening soil model with small-strain stiffness for serviceability limit state analyses of GREstructures[J].Proceedings of Geo Africa,22(10):1-5.
Ho S K,Rowe R K.1996.Effect of wall geometry on the behaviour of reinforced soil walls[J].Geotextiles and Geomembranes,14(10):521-541.
Huang B Q,Bathurst R J,Hatami K.2009.Numerical study of reinforced soil segmental walls using three different constitutive soil models[J].Journal of Geotechnical and Geoenvironmental Engineering,135(10):1486-1498.
Isabel M,Pinto M,Cousens T W.1996.Geotextile reinforced brick faced retaining walls[J].Geotextiles and Geomembranes,14(9):449-464.
Jie Y X,Bai Y L,Zheng B.2017.Study on critical slip surface of acceleration in slope stability analysis[J].Journal of Engineering Geology,25(5):1238-1244.
Mirmoradi S H,Ehrlich M.2014.Numerical evaluation of the behavior of GRS walls with segmental block facing under working stress conditions[J].Journal of Geotechnical and Geoenvironmental Engineering,141(3):4014109.
Mohamed S B A,Yang K H,Hung W Y.2014.Finite element analyses of two-tier geosynthetic-reinforced soil walls:Comparison involving centrifuge tests and limit equilibrium results[J].Computers and Geotechnics,61:67-84.
Rowe R K,Skinner G D.2001.Numerical analysis of geosynthetic reinforced retaining wall constructed on a layered soil foundation[J].Geotextiles and Geomembranes,19(7):387-412.
Shang Y H,Xu L R,Shang L,et al.2017.Effect of grid strength on pilesoil stress ratio of pile-net composite[J].Journal of Engineering Geology,25(1):95-101.
Wang R,Wang S,Peng D L.2016.Steel-plastic tenon geogrid and its interaction characteristics with backfills[J].Journal of Engineering Geology,24(3):391-397.
Yang K H,Zornberg J G,Liu C N,et al.2012.Stress distribution and development within geosynt-hetic-reinforced soil slopes[J].Geosynthetics International,19(1):62-78.
Yin Y P,Yan Y,Chen B,et al.2003.Deformation and failure of superhigh reinforced retaining wall and its remediation in wushan new town on the three-gorges reservoir[J].Journal of Engineering Geology,11(1):89-99.
Zhu D Y,Lee C F,Jiang H D.2003.Generalised framework of limit equilibrium methods for slope stability analysis[J].Géotechnique,53(4):377-395.
Zornberg J G.1996.Performance of geotextile-reinforced soil structures[J].University of California,Berkeley Dec,2769-2769.
常士骠,张苏民.2007.工程地质手册[M].北京:中国建筑工业出版社:96-152.
范乾权,张赞牢,姜玉泉.2010.国内覆土油罐现状探讨[J].中国储运,4:99-100.
介玉新,柏永亮,张彬.2017.边坡稳定分析中加速度临界滑动面研究[J].工程地质学报,25(5):1238-1244.
商拥辉,徐林荣,商丽,等.2017.格栅强度对桩-网复合地基桩-土应力比影响研究[J].工程地质学报,25(1):95-101.
王睿,王双,彭大雷.2016.钢塑凸榫土工格栅及其筋土界面特性研究[J].工程地质学报,24(3):391-397.
中国石油天然气集团公司.2014.立式圆筒形钢制焊接油罐设计规范[S].北京:中国计划出版社.