空气潜孔锤钻进技术在豫西抗旱找水打井施工中的应用          下载免费PDF全文

陈鑫发  牛建设 《探矿工程》2011,38(10):37-39

空气潜孔锤在豫西山区、严重缺水的基岩地区抗旱找水打井施工中发挥出了优越性。介绍了空气潜孔锤钻进技术工艺在豫西抗旱找水打井工程施工中的实际应用及其操作要点、钻进技术优势。同时分别对断裂破碎带地层和较完整地层中的空气潜孔锤钻进技术的应用效果进行了深入探讨和总结。  相似文献   

基于Geddes公式计算新型带肋预应力管桩的沉降     

熊厚仁  牛志荣  蒋元海  吴祥松  杨建永 《岩土力学》2011,32(12):3630-3636

在Geddes应力公式的基础上,对新型带肋预应力管桩的环状凸肋产生的影响做了假设:环状凸肋的受力可等效为对其下部土的挤密作用,即产生附加应力;为了方便计算,把该种附加应力简化沿环状凸肋两倍下部长度矩形分布的桩侧摩阻力,并推导出了适合新型带肋预应力管桩单桩沉降的计算公式;然后用Matlab软件进行编程计算。计算结果与现场试验结果相近,可做为工程估算。  相似文献   

弯曲河段床面分形特征及床面阻力试验研究   总被引：1，自引：0，他引：1       下载免费PDF全文

江磊  陈立  周银军  闫涛 《水科学进展》2011,22(4):502-508

根据概化水槽试验的结果,引入河床表面分形维数(以下简称BSD)用于河床表面形态的量化研究,并对BSD的计算方法、弯曲河道的分形特征及BSD值的大小与床面阻力的关系进行了探讨.结果表明,BSD的大小在大尺度上能够反映河段在纵向上的深泓起伏程度和横向的滩槽差,在小尺度上能反映河床表面相对的冲淤幅度,即弯曲河段床面具有明显的...  相似文献   

Differential herbivory of invasive algae by native fish in the Mediterranean Sea     

F. Tomas  E. Cebrian  E. Ballesteros 《Estuarine, Coastal and Shelf Science》2011

The potential role of generalist herbivores to serve as a source of biotic resistance against algal invasion in marine ecosystems has been poorly examined. The present study investigates the capacity of Mediterranean herbivorous fishes to consume three of the most invasive seaweeds of the Western Mediterranean (Caulerpa racemosa, Lophocladia lallemandii and Womersleyella setacea) and examines vertical and temporal variations of such consumption. Our results show that although fish feed throughout the depth gradient examined (5–35 m), they concentrate in shallow waters, and can consume high amounts of C. racemosa. Such high ingestion of C. racemosa does not appear to be random, since this alga is consistently chosen when offered in pairs with several native species. Conversely, L. lallemandii and W. setacea are barely eaten by fish even though they can be very abundant in the field throughout the year. Our results suggest that fish could be an important controlling agent that has been overlooked in temperate marine invasions, and they may be able to provide certain resistance to C. racemosa invasion. In contrast, they are unlikely to exert any important control effects on L. lallemandii or W. setacea.  相似文献   

堆内构件检测ROV设计与实现     

衣瑞文  张宝军  吴超  李文涛  葛彤 《海洋工程》2011,29(4):125-129

根据核堆内构件检测的需求,设计研发了一款超小型无人遥控潜水器(ROV)。从总体、结构、电控等方面,论述了该潜水器面临的问题和设计特点。着重论述了核环境下系统器件材料的耐辐照要求,并对关键器件进行了耐辐照性试验,结果表明所选器件能够满足辐照环境下的应用要求。最后给出了系统的水池实验结果,证明该系统具有良好的操纵性和稳定性。  相似文献   

ISO2394:2015 Annex D (Reliability of Geotechnical Structures)     

K.K. Phoon  J.V. Retief 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(3):125-127

ISO2394:2015 contains a new informative Annex D on “Reliability of Geotechnical Structures”. The emphasis in Annex D is to identify and characterize critical elements of the geotechnical reliability-based design process, while respecting the diversity of geotechnical engineering practice. This paper highlights the main features of Annex D and gaps for future work.  相似文献   

大直径深层钻孔灌注桩拔除工艺研究          下载免费PDF全文

裴迅  芮大虎  吴庆红  葛执礼 《探矿工程》2015,42(1):68-71

结合郑州南站连接线明挖隧道（拔桩区间）拟拔桩基直径大、桩长的特点,对桩体受力特征和拔桩工艺进行了研究。通过拔桩过程中桩周土破坏模式和桩体自身的抗拉强度分析计算,选取有效的减阻方法并应用于工程实践,取得良好效果。最后总结出大直径深层钻孔灌注桩拔除工程中桩身局部扩大、桩侧摩阻力过大和断桩等问题及相应的解决方法,供今后类似工程借鉴。  相似文献   

PDC钻头切削齿布齿设计的新思路          下载免费PDF全文

金永男  陈宗涛  由昌英  段隆臣 《探矿工程》2015,42(5):72-76

切削齿布齿设计是PDC钻头设计的关键。为提高PDC钻头的钻进效率,综合考虑PDC钻头切削齿的设计特点和切削先后顺序等因素,并且通过对PDC钻头单切削齿实验结果进行分析,提出了以冠部轮廓法线为基准的切削齿布齿设计方法。  相似文献   

岩质路堑边坡施工监测及稳定性分析     

王晓静 《测绘与空间地理信息》2015,(7)

以某高速公路岩质路堑边坡为例,通过施工现场监测及稳定性分析,结果显示初始设计状态下坡体深层位移和坡面位移接近滑动临界值。采取变更设计后,利用现场监测结合蒙特卡洛数值模拟的方法对该路堑边坡的加固效果进行稳定性和可靠性分析。经过加固后的边坡能较好地维持稳定,支护措施可靠。这种现场监测结合蒙特卡洛数值模拟的方法为路堑边坡的动态设计提供了依据,并能及时作出趋势性预测,为路堑岩质边坡的合理支护提供一种新的思路。  相似文献   

An Experimental Study on A Trapezoidal Pendulum Wave Energy Converter in Regular Waves     

王冬姣  邱守强  叶家玮 《海洋工程》2015,29(4):623-632

Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method (AM) was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator (RAO), primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0?1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%.  相似文献