大汶口盆地岩盐对接井钻探施工工艺研究          下载免费PDF全文

岳盈括 《探矿工程》2020,47(3):31-37，43

大汶口盆地蕴藏着丰富的岩盐资源,岩盐矿矿层埋深较深,上覆地层为古近系巨厚的松散泥岩、砂岩,易发生遇水软化,施工难度较大。山东肥城海晶盐化有限公司实施100万t/年卤折盐采输卤工程,实施卤井7组,每组井深约3000 m。定向对接井要求精准定点造斜、连续造斜。本文介绍了对接井施工中采用的关键施工工艺及MWD无线随钻测斜仪在定向钻进中进行钻井轨迹控制的应用实例。对如何在岩盐地层钻进、螺杆钻具应用、定点造斜等关键技术措施进行了详细阐述,以期为同类型卤水对接井项目施工中提供参考。  相似文献   

基于非差观测量的BDS+GPS近实时钟差估计     

郑涛  徐爱功  唐龙江  徐宗秋  杨虎 《测绘通报》2019,(5):39-43,76

卫星钟差的难预测性是影响实时高精度定位的重要因素之一。为快速获得高精度位置或对流层等信息，在非差观测模型的基础上，本文提出了一种延迟量约1 h的近实时钟差估计策略，该策略主要包含超快速轨道解算和钟差估计两部分。经验证，预报部分第2~5 h的GPS轨道三维平均精度为3.85 cm，BDS GEO和IGSO+MEO轨道三维平均精度分别为81.4和21.74 cm。基于超快速轨道可获得近实时钟差精度GPS为0.054 ns，BDS为0.12 ns。最后通过BDS+GPS静态PPP试验验证了轨道和钟差的可用性。  相似文献   

Mechanical properties of granular materials: A variational approach to grain‐scale simulations     

R. Holtzman  D. B. Silin  T. W. Patzek 《国际地质力学数值与分析法杂志》2009,33(3):391-404

The mechanical properties of cohesionless granular materials are evaluated from grain‐scale simulations. A three‐dimensional pack of spherical grains is loaded by incremental displacements of its boundaries. The deformation is described as a sequence of equilibrium configurations. Each configuration is characterized by a minimum of the total potential energy. This minimum is computed using a modification of the conjugate gradient algorithm. Our simulations capture the nonlinear, path‐dependent behavior of granular materials observed in experiments. Micromechanical analysis provides valuable insight into phenomena such as hysteresis, strain hardening and stress‐induced anisotropy. Estimates of the effective bulk modulus, obtained with no adjustment of material parameters, are in agreement with published experimental data. The model is applied to evaluate the effects of hydrate dissociation in marine sediments. Weakening of the sediment is quantified as a reduction in the effective elastic moduli. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

准地转理论基本问题回顾与讨论   总被引：3，自引：1，他引：2  

周小刚  王秀明  陶祖钰 《气象》2013,39(4):401-409

准地转理论是大气动力学的中心问题之一,它提供了从大气动力学基本原理入手分析大尺度天气系统演变的方法。准地转理论有助于预报员理解中高纬度大尺度天气系统的三维结构,分析、预报天气系统的发展和移动,因此被称为短期天气预报的理论基础。准地转理论具有完整的理论体系,它包含了较多的基本假定,故容易导致对其中的一些基本问题的理解有混淆。本文从基础的动力学知识出发,对准地转理论的基本概念、基本近似、核心理论及其在实际天气预报过程中的应用作了回顾和讨论。内容包括:准地转运动与准地转近似定义、准地转运动理论的范畴、天气图上的大尺度运动、准地转运动理论与短期天气预报的关系、由斜压二层模式下的准地转理论对高空槽脊和地面气旋发展与移动的判断等。  相似文献   

Fast Periodic Transfer Orbits in the Sun–Earth–Moon Quasi-Bicircular Problem     

A. M. Leiva  C. B. Briozzo 《Celestial Mechanics and Dynamical Astronomy》2005,91(3-4):357-372

Starting from the identification and classification of a family of fast periodic transfer orbits in the Earth–Moon planar circular Restricted Three Body Problem (RTBP), and using analytic continuation techniques, we find two unstable periodic orbits in the Sun–Earth–Moon Quasi-Bicircular Problem (QBCP). The orbits found perform periodic Earth–Moon transfers with a period of approximately 29.5 days.  相似文献   

带反馈优先的M/M/c排队在通信网络中的应用     

厉莉  朱翼隽 《成都信息工程学院学报》2006,21(6):897-902

在具有Bernoulli反馈的单队列单服务台排队模型的基础上，考虑通信网络中赋予反馈信元优先权的情况，将单个服务台推广到多个服务台，建立了具有反馈优先的M／M／c排队模型．在该排队模型中，信元的到达遵循泊松过程，服务时间服从指数分布，通过构造拟生灭过程和运用谱展开方法给出了平稳队长分布的算法，具体给出了C=2时平稳队长分布的显式表达式，以及在反馈优先和反馈非优先两种策略下的排队指标，并作出了相应的指标性能分析，得出信元在反馈优先策略下的平均逗留时间较短，进而说明了该排队模型在通信网络中有广泛的应用价值。  相似文献   

青藏高原中部似大地水准面精化的应用研究     

王革胜  曹学成  高海容  李辉 《测绘与空间地理信息》2014,(7):187-189,196

介绍了精化似大地水准面的常用方法。采用青海和西藏三级GPS大地控制网测量数据,利用移动曲面法、改进的移动曲面法、二次曲面拟合法和改进的二次曲面拟合法对青藏高原中部似大地水准面进行了拟合计算。结果表明,利用改进的移动曲面法和改进的二次曲面法能有效地提高本地区似大地水准面的精化效果,精度优于0.5 m。  相似文献   

ADS80影像在甘肃省地理国情普查正射影像生产中的应用     

曹正响 《东北测绘》2014,(6):125-126,130

结合甘肃省第一次地理国情普查数字正射影像生产工作,介绍了ADS80影像数据在正射影像生产中的应用,并对关键技术环节进行了阐述。  相似文献   

随钻测量信号中继器的设计与实现   总被引：2，自引：0，他引：2  

王岚 《煤田地质与勘探》2013,41(1):82-83

为解决随钻测量系统信号在传输中衰减的问题,设计研制了随钻测量信号中继器,在钻孔到达一定深度测量系统信号衰减严重时,在两根中心通缆式钻杆间接入中继器继续测量,有效地解决了信号衰减问题,增强了信号驱动能力,延长了信号的传输距离,保证了随钻定向测量系统的正常工作。   相似文献   

Force–displacement mixed control for collapse tests of multistory buildings using quasi‐static loading systems          下载免费PDF全文

Peng Pan  Gang Zhao  Xinzheng Lu  Kailai Deng 《地震工程与结构动力学》2014,43(2):287-300

In quasi‐static tests for structures with multi‐DOF, the forces exerted to the structures commonly follow a prescribed force profile, for example, triangular pattern and/or uniform pattern. Therefore, force control is the natural choice. However, force control is no longer applicable when the specimens sustain significant stiffness and strength degradation, particularly in collapse tests. To solve this problem, a force–displacement mixed control algorithm is proposed, which is able to achieve stable control in quasi‐static tests following prescribed force profiles. On the basis of the FlexTest IIm platform of the MTS Systems Corporation (14000 Technology Dr, Eden Prairie, MN 55344 United States), a test program named Tsinghua University mixed control test program, which uses a mixed control algorithm, was developed. The algorithm was initially applied to an elastic test of a cantilever column to verify its accuracy and stability and then to a collapse test of a multistory RC frame to investigate its effectiveness. In the collapse test, the effects of major control parameters, that is, the number of iterative rounds and the loading time of each round on the control accuracy, were also studied. The test results show that the test program applying the mixed control algorithm can achieve stable control of the collapse tests maintaining the expected force profile. Increasing the number of iterative rounds and the loading time of each round can improve the control accuracy. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献