考虑滑床不同地基系数的抗滑桩受力特征研究   总被引：1，自引：0，他引：1  

詹红志  王亮清  王昌硕  张楠 《岩土力学》2014,35(Z2):250-256

基于目前在抗滑桩理论研究方面多将滑床层状地层等效成均质体,在多层地基横向受荷桩挠曲微分方程的基础上,推导出考虑滑床不同地基系数的弹性抗滑桩嵌固段变位、内力和应力计算的公式。用Matlab软件编写了抗滑桩变位、内力和应力计算与图形处理程序,有效提高了抗滑桩变位、内力和应力分析效率和计算精度。工程实例表明,考虑滑床不同地基系数计算方法对比等效法,滑面处位移、滑面处转角、剪力最大值、弯矩最大值分别增大25.76%、18.04%、14.90%和4.16%,而滑动面处桩侧应力较等效法减小44.91%。该研究成果对滑坡为不同岩性的岩体进行抗滑桩设计具有指导意义。  相似文献   

Experimental study on the settlement of marine deposits of Anzali under cyclic loading by laminar box apparatus     

Hadi Ahmadi  Abolfazl Eslami  Mahyar Arabani 《Marine Georesources & Geotechnology》2017,35(3):330-338

The central Alborz mountain range, located in northern Iran, neighboring the Caspian Sea and where the two Persia and Eurasia plates meet, is known as a seismologically active area. In this regard, investigation of the behavior of saturated sand deposits located in this area may be of particular interest. Saturated sand deposits are subjected to instabilities owing to liquefaction or volume change due to earthquake shakings. A particular type of saturated sand deposits is Anzali sand which is abundant in Anzali port and other cities located in this area in northern Iran. This type of sand is a representative for most sands found in this area, i.e., the southern coastal line of Caspian Sea. This research is solely focused on the volume change behavior of marine deposits of Anzali area, often characterized as Anzali sand, in terms of the settlement of a model footing located on the surface of the sand by the aid of a transparent laminar shear box apparatus. Effects of a number of factors such as the frequency of the cyclic loading, the initial density of the sand, and the sample preparation method have been investigated. Observations indicated that the density index and the frequency of loading which are proportional to the energy of an earthquake have direct effects on the accumulation and amount of the final settlement of Anzali sand.  相似文献   

Sponge disease in the Adriatic Sea     

Cristina G. Di Camillo  Igor Bartolucci  Carlo Cerrano  Giorgio Bavestrello 《Marine Ecology》2013,34(1):62-71

A mass mortality episode involving three marine dyctioceratid sponges, Ircina variabilis, Sarcotragus spinosulus and Spongia officinalis, was observed on ‘Scoglio del Trave’ (Conero Promontory, North Adriatic Sea) in late summer 2009. In this area, calm sea and high temperatures throughout summer created unfavorable environmental conditions, leading to the outbreak of the disease. Affected specimens showed evident necrotic areas and portions with bare skeleton, and many specimens of S. spinosulus were covered with a white mat of cyanobacteria. In September 2009, about 22% of these demosponges suffered from this disease. The mortality event ceased when sea temperature dropped below 20 °C. Small specimens turned out to be more sensitive to the diseases, whereas the damaged tissues of large specimens were able to recover. In October, the damaged specimens were detached by the rough sea and more than 900 beached sponges were found along the 1‐km‐long beach, showing the seriousness of the phenomenon, which probably involved not only the area studied but also areas adjacent to it.  相似文献   

超急性期脑梗塞的影像学诊断   总被引：6，自引：0，他引：6  

张在沛 《CT理论与应用研究》2003,12(4):31-35

目的：脑梗塞是严重威胁人类健康的常见病，临床上往往需要早期诊断脑梗塞以便选择治疗方案。方法：查阅中外相关文献资料并结合临床工作实际。结果：客观评价超急性期脑梗塞的影像学诊断方法及其应用价值。结论：提出多层螺旋CT和功能性MRI是目前诊断该病的最佳方法。  相似文献   

牛顿内摩擦定律和达西定律的改进     

熊道锟 《岩土工程技术》2004,18(6):275-278

根据物体运动的摩擦力定律和物体变形破坏的库仑定律对牛顿内摩擦定律作了改进 ,进而改进了达西定律。用改进的达西定律与实验资料进行拟合 ,阐述了达西定律与实际偏离的原因。  相似文献   

脑卒中与天气过程的关系   总被引：6，自引：1，他引：6  

印佩芳  马辛宇  袁军  张淑云  袭建强  许显福 《气象》1993,19(12):44-47

根据浙江人民医院急诊科１９８５－１９８９年１８４例脑卒中病例，结合杭州市气象要素和浙江省气象台历史天气图资料，以综合的动态观点，采用统计及合成分析方法，得出脑卒中易发时段与天气过程的基本关系，建立起概念模式，进而普查造成天气过程的主要天气系统和发病日的天气形势，可供在气象预报的基础上预测脑卒中易发时段，为医学气象预测咨询提供依据。  相似文献   

刚度可调层状多向剪切模型箱的研制及性能测试     

郑森  李伟华  崔杰  李亚东 《岩土力学》2022,43(Z2):616-625

为满足不同场地条件下岩土工程振动台试验的需求,在总结国内外振动台试验土箱经验的基础上,研制了刚度可调的层状多向剪切模型箱。该剪切箱由系列空心环形钢框架堆叠而成,层间由滚珠和螺杆相连,高度可根据试验工况改变,通过调节螺杆的刚度、数量和排列方式等,实现其刚度变化。利用ABAQUS软件分析得出各种组合模型箱的特征频率,验证了箱体刚度可调的特性。运用该模型箱开展了自由场振动台试验,分析了不同高度、距箱侧壁不同距离处观测点的加速度时程及其相应反应谱,并采用2-范数偏差指数对边界效应进行量化。结果表明,新研制的层状剪切箱无明显的边界效应,能较好地实现自由场地在平面内的动力响应。  相似文献   

酒泉盆地下白垩统藻纹层分布特征及其与油气的关系   总被引：1，自引：1，他引：0  

马立元  程克明  刘大锰  熊英 《沉积学报》2007,25(1):147-153

酒泉盆地下白垩统纹层状泥质白云岩和白云质泥岩中有机纹层（藻纹层）结构发育,但非均质性很强,主要表现在相同层位不同地区及同一钻井不同深度藻纹层的含量悬殊。藻纹层的分布与发育都受到沉积相及相变的控制。藻纹层主要是由浮游藻类及其降解产物组成,藻类以绿藻门绿枝藻科的圆球藻为主要属种。藻纹层含量与源岩的生烃潜力呈正相关关系。酒西坳陷已发现的大部分原油主要源于下白垩统下沟组藻纹层泥质白云岩,表明藻纹层是酒泉盆地很重要的一种生烃物质,与酒泉盆地的油气具有密切的成生联系。富含有机质纹层的湖相碳酸盐岩不仅是优质的烃源岩,而且由于其生烃物质的层状富集,在生、排烃过程中,更有利于间隙微裂缝的形成和排烃。  相似文献   

磁共振成像早期诊断激素诱导股骨头缺血性坏死     

尹晓明  邓刚  李宝平  常鑫  王军  李萍  曾庆玉 《CT理论与应用研究》2006,15(1):29-32

目的探讨激素诱导股骨头缺血性坏死早期磁共振成像特征,和激素应用剂量,时间长短与股骨头缺血性坏死之间关系。材料和方法对108例患者有短期大量激素应用史患者行双髋关节平片及磁共振成像检查,分析图像特征,并应用统计学方法评价股骨头坏死与激素的关系。结果108例平片检查均为阴性,磁共振成像出现异常征象者35例,激素总量,日最大剂量及应用时间与股骨头坏死有统计学意义。结论:磁共振成像可以早期诊断激素诱导股骨头缺血性坏死,影像上单线征和双线征具有特异性;激素可以导致股骨头缺血性坏死。  相似文献   

十足类甲壳动物受精细胞学研究进展   总被引：6，自引：2，他引：4  

杨万喜  姜乃澄 《海洋学研究》1998,16(4):57-63

结合作者近期的研究工作,从精卵识别、顶体反应、皮层反应、雌雄原核的形成和结合等方面综述了近年来十足类甲壳动物受精细胞学方面的研究成果,并展望了这一领域的研究与应用前景。  相似文献