浅埋集输油管线拟稳态温度场及热工计算   总被引：9，自引：6，他引：9  

李南生  丁德文 《冰川冻土》1997,19(1):65-72

从二维相变热传导方程出发，应用保角变换将研究区域规整化，在热力等效原理基础上导出冬季冻结期输油管拟稳态温度公式，并由此给出保温隔热层厚度，管线散热量，管道轴向温降，管道上部最大冻深，冻结速率，系统热阻热工公式。  相似文献   

Seismic vulnerability evaluation of axially loaded steel built-up laced members Ⅰ: experimental results     

Kangmin Lee  Michel Bruneau 《地震工程与工程振动(英文版)》2008,7(2)

An experimental program was initiated to investigate the seismic performance of built-up laced steel bracemembers. Quasi-static testing of twelve typical steel built-up laced member (BLM) specimens was conducted. These weredesigned to span a range of parameters typically encountered for such members based on findings from a survey of commonlyused shapes and details that have been historically used. The specimens were subdivided into groups of three different cross-sectional shapes, namely built-up Ⅰ-shape section, and built-up box shapes buckling about the x or the y axis. Within eachgroup, global and local buckling slenderness ratios had either kl/r values of 60 or 120, and b/t ratios of 8 or 16. The specificinelastic cyclic behavior germane to each specimen, and general observations on overall member hysteretic behavior as afunction of the considered parameters, are reported. A companion paper (Lee and Bruneau 2008) investigates this observedresponse against predictions from analytical models, and behavior in the perspective of system performance.  相似文献   

预应力混凝土空间框架节点二维拟静力试验研究   总被引：1，自引：0，他引：1  

李旭红  房贞政  陈浩德 《地震工程与工程振动》2009,29(1)

采用拟静力试验方法对预应力混凝土和普通钢筋混凝土空间框架内节点进行了不同轴压比下单、双向循环加载的试验研究,得到不同加载方式下试件的滞回曲线。分析了各个试件的破坏形式、承载力、刚度、延性及耗能能力,通过比较和对滞回曲线的分析得出：双向水平荷载作用对构件耦合作用明显,构件存在扭转效应,构件的强度退化和刚度退化比单向荷载作用严重,节点的耗能能力降低。  相似文献   

Recent progress of seismic research on tall buildings in China Mainland     

Qian Jiaru  Li Ningbo  Ji Xiaodong  Zhao Zuozhou 《地震工程与工程振动(英文版)》2014,13(1):47-57

To study the seismic behavior of high strength concrete fi lled double-tube(CFDT) columns,each consisting of an external square steel tube and an internal circular steel tube,quasi-static tests on eight CFDT column specimens were conducted.The test variables included the width-to-thickness ratio(β1) and the area ratio(β2) of the square steel tube,the wall thickness of the circular steel tube,and the axial force(or the axial force ratio) applied to the CFDT columns.The test results indicate that for CFDT columns with a square steel tube with β1 of 50.1 and 24.5,local buckling of the specimen was found at a drift ratio of 1/150 and 1/50,respectively.The lateral force-displacement hysteretic loops of all specimens were plump and stable.Reducing the width-to-thickness ratio of the square steel tube,increasing its area ratio,or increasing the wall thickness of the internal circular steel tube,led to an increased fl exural strength and deformation capacity of the specimens.Increasing the design value of the axial force ratio from 0.8 to 1.0 may increase the fl exural strength of the specimens,while it may also decrease the ultimate deformation capacity of the specimen with β1 of 50.1.  相似文献   

层状岩体边坡动态稳定性拟静力上限分析     

赵炼恒  罗强  李亮  杨峰  但汉成 《岩土力学》2010,31(11):3627-3634

将强度折减技术与极限分析上限定理结合,利用安全系数Fs评定指标对层状岩体边坡进行稳定性上限分析,与已有研究成果进行了对比分析,并较为详细地分析了相关参数对层状岩体坡体安全系数和潜在破裂面的影响。分析结果表明,与同类计算方法的对比可以证明表明文中方法的正确性;边坡安全系数和破坏范围受边坡坡度、岩体重度、边坡高度、动载效应系数和岩层倾角的控制;当岩层倾角处于一定范围时,层状岩体边坡发生顺层失稳的可能性最大,工程中需特别注意。  相似文献   

导电半空间瞬变电磁响应规律的探讨     

王小明 《地球科学与环境学报》1989,(2)

本文从电磁场基本方程出发引入标量函数F,讨论了磁偶极源激发下导电半空间瞬变电磁场的传播规律,从理论上证明了“烟圈”效应的存在性,得到了一些有益的结论。  相似文献   

前陆冲断带非对称性变形与逆冲断层运动学指向     

陈书平  万华川  袁浩伟  王信棚  黄学尧 《地质力学学报》2022,28(2):182-190

前陆冲断带冲断层的冲断方向一直没有得到理论解释.文中基于库伦断裂理论和造山带前陆冲断带变形的非对称性,分析了前冲断层和反冲断层的成因.变形初期将会出现两组共轭势断裂面,随后在变形非对称引起的准静力平衡条件下,两组势断裂面中所需作用力小的那组断裂面将更容易发育成冲断层,断层滑动所需作用力包括克服滑脱面摩擦力和断层面摩擦力...  相似文献   

基于准静定方法的多成分锚泊线优化   总被引：2，自引：1，他引：1  

余龙  谭家华 《海洋工程》2005,23(1):69-73

移动式海洋平台锚泊系统通常用锚索或锚链等多种成分合成的锚泊线,因而涉及参数较多给设计分析带来不便。针对这一问题,基于准静定方法推导限定水深下多成分锚泊线悬链线方程,并考虑锚泊线组成成分的参数对锚泊系统回复力的影响,建立目标函数最小化的多成分锚泊线优化设计模型。采用遗传算法对南海2号锚泊系统的改造进行分析求解,得到有益的结论。  相似文献