用试桩值反演分析不同土体预应力砼管桩参数          下载免费PDF全文

陈良州 《探矿工程》2004,31(7):1-4

通过3个场地试桩资料反演分析，取得不同土体管桩参数选取原则与方法初步成果：砂性土侧阻力、端阻力可据实测标贯击数加5击后的密实度按桩基规范选取，且具有桩端进入持力层越深端阻力越大的特点，甚至可将砾砂的端阻力提高到卵石挡选取；上更新统粘性土侧阻力、端阻力亦可据实测液性指数提高一挡或半挡按桩基规范选取；全新统粘性土、上更新统粉土侧阻力可据实测液化指数或密实度直接按桩基规范选取。  相似文献   

某越江隧道顶管工作井基坑降水方法应用     

袁修锦  潘启章等 《中国煤田地质》2002,14(2):49-52

位于上海浦东地区的越江隧道顶管工作井施工基坑距黄浦江防风墙45m,距煤气公司煤气井仪表室1.20m。基坑开挖底界(深度32.45m)为场地内第⑦土层承压含水层顶部(静止水位-6.40m)。为保证基坑施工及临近建筑物的安全,避免基坑降水造成砂土流失而引起的地面沉降问题,在降水井的施工中,根据含水介质的颗粒级配选择相应规格的过滤砂作为过滤层填料,并保证过滤层具有一定的厚度,使降水时的含砂量控制在1/10万以下;采用非稳定流控制水位跟踪作业降水法,尽量减少基坑降水的影响范围,取得了良好的预期效果。  相似文献   

用管棚实现超前支护的实践   总被引：2，自引：0，他引：2  

王东鸣 《四川地质学报》2002,22(Z1):34-35

介绍在隧道严重塌方段，采用管棚实现一次20m超前支护的实践经验。  相似文献   

砂钻的双管冲击内管取心工艺     

李树海 《黄金地质》2002,8(2):58-61

为提高砂矿勘查的施工效果，将取样内管立在套管钻头的内台肩上，冲击钻进1个回次后，将内管提升至地面采集样品。套管及内管分别采用φ152和127mm的地质钢管。钻头用35CrM钢锻造，内径大于110mm。吊锤重量300kg。一般孔内故障用抽筒、吊锤和劈刀即可排除。采集的样品基本保持原生结构。只要严格按照规程施工，钻孔的各项指标均能满足地质要求。  相似文献   

高密度电法在金矿找矿中的应用   总被引：6，自引：1，他引：6  

王文龙  杨拴海  张慧玉  马德锡  肖力  陈瑞林 《黄金地质》2002,8(3):53-56

以岩（矿）石的导电性和激电效应差异为基础，沿测线同时布设几十到几百根电极，仪器按选定的供电，测量排列方式自动采集电位值，并进行滤波，地改，计算等处理，可探测深度在150m以上的电阻率和充电率的精细结构，用以推断精细的地质和电子型导电矿物结构，在不同地区，不同类型的已知金矿床的试验表明，高密度电法异常与矿体在空间位置上十分吻合，在未知区，在异常区施工QZ14-2钻孔，发现了地下38m的盲矿体，取得了满意的试验和找矿效果。  相似文献   

城市地下管线普查数据处理系统设计     

张国林 《测绘与空间地理信息》2002,25(3):50-51,56

主要阐述一套比较完善的城市地下管线外业普查数据处理系统的实现过程。  相似文献   

钻孔灌注桩设备及机具选择与设计     

丁兴敏  卢予北 《地质与勘探》1995,31(6):54-57

在收集大量资料基础上，根据多年实际经验结合国内现有设备，提出了不同情况下合理选择设备的原则，对灌浆导管、灌浆装置和钻头设计，提出了新的看法和改进措施。  相似文献   

The effects of drag reduction by ribbons attached to cylindrical pipes   总被引：1，自引：0，他引：1  

S. H. Kwon  J. W. Cho  J. S. Park  H. S. Choi 《Ocean Engineering》2002,29(15):1945-1958

This study proposes a drag reduction device that uses three ribbons attached 120 degree apart to vertical pipes. Experiments were conducted in a circulating water channel to investigate the effects of the ribbon length and the direction of the flow on various current velocities. Drag on a vertical cylinder was measured by a resistance dynamometer. Flow visualizations were conducted using laser sheet beams. Laser Doppler Velocimetry (LDV) was used to measure the velocity field in the wake. This experiment demonstrates that attached ribbons can be used to reduce the drag force on vertical pipes for various directions of incoming flows. The ribbon-type device is very simple and easy to fabricate for field applications. The results are promising for the application to offshore structures.  相似文献   

A study of spar buoy floating breakwater     

Nai-Kuang Liang  Jen-Sheng Huang  Chih-Fei Li 《Ocean Engineering》2004,31(1):43-60

A floating breakwater produces less environmental impact, but is easily destroyed by large waves. In this paper, the spar buoy floating breakwater is introduced with a study on the wave reflection and transmission characteristics and mooring line tension induced by the waves. Mei (The Applied Dynamics of Ocean Surface Waves, Wiley, New York (1983) 740 p) proposed a theoretical solution for the reflection and transmission coefficients as the wave propagates through a one-layer slotted barrier. For a multiple-layer fence system, the analytical solution is proposed linearly. The results show that the theoretical computations agree well with the experimental trends. For a multiple-layer fence system, the transmission coefficients become maximal as the layer spacing to wavelength ratio moves to 1/2. Conversely, the coefficients become minimal, as the ratio moves to 0.3. To estimate the maximum tension of the mooring line, both numerical calculations and laboratory experiments were executed. The numerical calculation results were similar to the experimental results.  相似文献   

Regular wave pressures and forces on submerged pipelines near a sloping boundary     

K. A. Roopsekhar  V. Sundar 《Ocean Engineering》2004,31(17-18):2295-2317

The hydrodynamic pressures induced by regular waves around the circumference of a pipeline normal to the wave direction and near a rigid bed of slope 1:10 have been investigated in a wave flume. The pressures were integrated to obtain the force time history, from which the peak horizontal and vertical forces are evaluated. The maximum and root mean square horizontal and transverse force coefficients are correlated with the Keulegan–Carpenter (KC) number. The effect of the distance between the sloping bed and the pipeline on the force coefficients is discussed. The force coefficients are found to decrease with an increase in KC number and with the decrease in the relative clearance of the pipeline from the boundary. In addition, the reflection characteristics of the sloping bed in the presence of the pipeline as a function of surf similarity parameter and their comparison with the results from existing literature are also reported. The details of the model setup, experimental procedure, results and discussion are presented in this paper.  相似文献