LNG接收站港池水深扫测技术

液化天然气作为清洁能源,在能源行业正在迅猛发展。而LNG码头区域由于受到潮流等因素掀起的海底泥沙的影响,导致水下回淤严重,直接威胁到LNG接卸船通航的安全。本文以粤东LNG为例,系统阐述了港池水深扫测技术,并根据调查结果提出合理化建议,推动LNG产业高质量发展。

多种混合格式CAD水深数据的智能识别提取

在CAD水深测量成果图中,水深往往以分离的文本方式标注,其整数、小数、小数点、负号等各部分相互分离且形式多样,这给水深信息提取工作带来了很大的困难。本文基于空间数据关联规则挖掘思想,建立空间布局拓扑表,采用人工神经网络学习和分类识别方法,智能识别和提取水深数据。此方法无需预先指定格式及其他参数,创新性实现了多种混合格式水深数据的自动化、智能化识别提取,且准确率高、速度快,在工程领域具有一定应用前景和推广价值。

水深测量周期的研究

根据海底地形研究成果和历史测量数据 ,分析了近海地形的稳定性及其分类 ,对部分海域的地形变化速率进行了计算 ,初步划分了测量周期覆盖区域。指出了水深测线密度、地形测量信息及应用程度是影响测量周期的重要因素 ,对部分测绘技术的实施提出了一些建议。

水深遥感与潮滩地形冲淤变化分析

遥感及地理信息系统技术在海岸动力研究领域和工程规划设计方面的应用前景十分广阔。本文介绍了将这两种技术结合起来用于测量潮汐水道及湖滩水深，计算和分析淤泥质潮滩冲淤演变过程的方法，其测量手段的科学性、先进性，计算的精确性和模拟显示的直观性，都是以往方法无法比拟的。文章还以长江口南支和舟山两地研究的成果介绍了这一技术的应用情况。相信这一技术在海岸带开发利用以及近海工程、航运、水利、环保等方面都具有很大的社会效益和经济效益。

40万吨级VLOC满载通行渤海乘潮窗口期探索

通过介绍渤海深水航线的最新扫测数据、渤海潮汐特点及船舶乘潮窗口期,分析40万吨级超大型矿砂船(VLOC)满载乘潮实际通行渤海的航海实践,总结40万吨级VLOC满载西行渤海直靠曹妃甸港的重要突破和宝贵经验,为大型深吃水船舶,尤其是40万吨级VLOC满载通行渤海充分利用潮汐提供参考借鉴。

新一代全球海底地形模型BAT_WHU2020

本文利用由多源卫星测高资料计算的新版全球重力异常Grav_Alti_WHU,联合船测水深资料,构建了全球75°S—70°N范围的1′×1′海底地形模型BAT_WHU2020。以船测水深、现有模型和多波束测深数据为参考,对模型精度进行了分析评价。结果表明,在中国海域及邻区(104°E—160°E,0°N—50°N),本文模型与船测水深之差值的标准差约70 m,与SIO V19.1模型精度相当,优于ETOPO1、DTU10、GEBCO_08等模型,较此前发布的BAT_VGG模型精度提高了约30%,说明本文模型构建方法可靠、数据处理准确、精度较高。在全球范围内,BAT_WHU2020模型与船测水深之差值的标准差为50~65 m,差值在±200 m范围内的比率超过95%,与SIO V19.1模型精度相当,优于ETOPO1、DTU10、GEBCO_08等模型,较BAT_VGG模型精度提高了27%~36%。以SIO V19.1模型为参考,模型之差的标准差为90~110 m,约90%格网点差值在±200 m以内,约95%格网点差值在±300 m以内,两者一致性良好。最后,讨论了地壳均衡、Parker公式高次项等对成果精度的影响,模型的真实空间分辨率,以及以多波束测深为参考的模型精度问题。分析认为,BAT_WHU2020模型空间分辨率为10~18 km,在马里亚纳海沟、麦夸里海岭地区相对精度为5%~6%。

Determination of minimum cover depth for shallow tunnel subjected to water pressure

Prediction of the state of roof collapse is a big challenge in tunnel engineering, while the limit analysis theory makes it possible to derive the analytical solutions of the collapse mechanisms. In this work, an exact solution of collapsing shape in shallow underwater tunnel is obtained by using the variation principle and the upper bound theorem based on nonlinear failure criterion. Numerical results under the effect of river water and supporting pressure are derived and discussed. The maximum water depth above the river bottom surface is determined under a given buried depth of shallow cavities and the critical depth of roof collapse is obtained under a constant river depth. In comparison with the previous results, the present solution shows a good agreement with the practical results.

Multiple sub-array beamspace CAATI algorithm for multi-beam bathymetry system

This paper extends CAATI （Computed Angle-of-Arrival Transient Imaging） technique of Multi-angle Swath Bathymetry Sidesean Sonar （MSBSS） into Multi-Beam Bathymetry Sonar （MBBS） and presents a new Multiple Sub-array Beamspaee - CAATI （MSB-CAATI） algorithm. The method not only can achieve high resolution seafloor mapping in the whole wide swath, but also can work well in complex acoustic environments or geometries. Simulation results and processing results of sea-experiment data prove the validity and superiority of the algorithm.

A Fast Algorithm of Cartographic Sounding Selection

An effective strategy and framework that adequately integrate the automated and manual processes for fast cartographic sounding selection is presented. The important submarine topographic features are extracted for important soundings selection, and an improved "influence circle" algorithm is introduced for sounding selection. For automatic configuration of soundings distribution pattern, a special algorithm considering multi factors is employed. A semi automatic method for solving the ambiguous conflicts is described. On the basis of the algorithms and strategies a system named HGIS for fast cartographic sounding selection is developed and applied in Chinese Marine Safety Administration Bureau (CMSAB). The application experiments show that the system is effective and reliable. At last some conclusions and the future work are given.

Determining areas in an inclined coal seam floor prone to water-inrush by micro-seismic monitoring

The failure depth of the coal seam floor is one important consideration that must be kept in mind when mining is carried out above a confined aquifer.Determining the floor failure depth is the essential precondition for predicting the water-resisting ability of the floor.We have used a high-precision microseismic monitoring technique to overcome the limited amount of data available from field measurements. The failure depth of a coal seam floor,especially an inclined coal seam floor,may be more accurately estimated by monitoring the continuous,dynamic failure of the floor.The monitoring results indicate the failure depth of the coal seam floor near the workface conveyance roadway（the lower crossheading） is deeper and that the failure range is wider here compared to the coal seam floor near the return airway（the upper crossheading）.The results of micro-seismic monitoring show that the dangerous area for water-inrush from the coal seam floor may be identified.This provides an important field measurement that helps ensure safe and highly efficient mining of the inclined coal seam above the confined aquifer at the Taoyuan Coal Mine.

Evaluating the maneuverability of a new type of self-propelled barge

A new type of self-propelled barge was designed specifically for use on the Chishui River. This paper presents experimental results of its performance from tests in water of different depths,while bearing different loads. For test purposes,one of the best self-propelled barges from the Chishui River was used as a performance reference. The comparison showed that the new design has better maneuvering performance.

黄骅港航道大风淤积应急预报系统的应用研究

黄骅港航道受大风骤淤影响严重,目前的主要解决措施是在风后进行应急疏浚,但仍面临难题:常规的风后测图和数值模拟均需要较长的时间,无法立即得知航道骤淤情况,因此风后的应急疏浚具有一定的盲目性。文章根据黄骅港航道多年回淤研究成果,实现大风骤淤的准同步预报,结合风前航道水深测图,推算风后航道沿程维护方量,对黄骅港航道风后应急疏浚具有重要指导意义。

Civil3D在跨海大桥冲刷防护设计中的应用

本文针对跨海大桥的桥墩冲刷防护设计中地形断面图绘制工作难度大和工程量统计计算工作量大的问题,引入Civil3D的强大地形处理功能,结合二次开发的VBA程序,建立了跨海大桥冲刷地形文件,运用Civil3D纵断面图功能绘制跨海大桥冲刷地形断面图。通过Civil3D统计计算功能,自动汇算冲刷地形的防护工程量。.通过与传统算量软件HTCAD的土方量计算值、实际工程的土方量相比,Civil3D计算土方量误差较小,在工程允许范围内,可以直接用于工程量计算。本文利用Civil3D二次开发的成果完成了跨海大桥冲刷防护工程量的计算,计算成果应用于工程实际,取得良好的应用效果。因此本文研究成果为类似工程的工程设计提供参考。

Pull-out tests and slope stability analyses of nailing systems comprising single and multi rebars with grouted cement

The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.

Determining the Optimum Inflow Rates for Micro-flood Irrigation on the Tukulu Soil

The performance of micro flood irrigation （MFI） under different inflow rates was evaluated on 90 m closed ended furrows in the South African Tukulu soil. A single irrigation was used to characterise the surface and subsurface soil water distribution from the 20, 40, 80 and 160 L/min inflow rates treatments. Neutron access tubes were installed to a depth of 1 m at every 10 m distance interval starting at 5 m from the furrow inlet. Soil water content measurements were taken using the WaterMan neutron water meter. The HYDRUS-2D software was also used to provide insight on irrigated furrows soil water content and subsurface water distribution. The 20 L/min produced a stream flow that could advance up to the 60 m furrow distance. The stream flow from the rest of the inflow rates were able to reach the furrow end with the 180 L/min recording the fastest advance time of 23 min. The 20 L/min and 40 L/min had recession period of less than 7 min while the 80 L/rain and 160 L/min lasted more than an hour. Distribution uniformity （DU） at longer furrow distances was the highest from the 80 L/min and 160 L/min with the 20 L/min and 40 L/min recorded similar performances at shorter distances. The 40 L/rain was one of the smaller inflow rates that recorded the highest DU of 0.96 for the generated average infiltrated depth of the 30 m long furrow and therefore should be adopted for furrow distances of less than 60 m on the Tukulu soil.

A Field Investigation on the Effects of Background Erosion on the Free Span Development of a Submarine Pipeline

The safety of submarine pipelines is largely influenced by free spans and corrosions. Previous studies on free spans caused by seabed scours are mainly based on the stable environment, where the background seabed scour is in equilibrium and the soil is homogeneous. To study the effects of background erosion on the free span development of subsea pipelines, a submarine pipe- line located at the abandoned Yellow River subaqueous delta lobe was investigated with an integrated surveying system which in- eluded a Multibeam bathymetric system, a dual-frequency side-scan sonar, a high resolution sub-bottom profiler, and a Magnetic Flux Leakage （MFL） sensor. We found that seabed homogeneity has a great influence on the free span development of the pipeline. More specifically, for homogeneous background scours, the morphology of scour hole below the pipeline is quite similar to that without the background scour, whereas for inhomogeneous background scour, the nature of spanning is mainly dependent on the evolution of seabed morphology near the pipeline. Magnetic Flux Leakage （MFL） detection results also reveal the possible connec- tion between long free spans and accelerated corrosion of the pipeline.

Hydrophilic characteristics of soft rock in deep mines

A series of water absorption tests on dried soft rock have been conducted by the intelligent testing system for water absorption tests in deep soft rock, including tests of water absorption with and without pres- sure. The results show that the water absorbing capacity of rock with a certain pressure is larger than that of rock without pressure： however, the relationship between the water absorbing percentage and the time can be expressed by w（t） = a（l - e^-bt）. In hi-logarithmic coordinates, the hydrophilic relationship with time in tests with pressure could be characterized by linearity, while they present concave or convex in tests without pressure. Based on the hypothesis that each influential factor is irrelevant and they have a linear correlation with the water absorbing capacity, we calculated the weight coefficient of each factor according to experimental results under different conditions. The calculations demonstrate that the effec- tive porosity, content of smectite and kaolinite are all positively correlated with the water absorption capacity of rock; meanwhile, the fractal dimension of the effective pores presents a negative correlation with the water absorption capacity of rock. The water absorption capacity with pressure increases with increasing illite, chlorite and chlorite/smectite formation and a decrease in illite/smectite formation and the fractal dimension of the effective pores, while it is opposite in tests without pressure. The weight coefficient of smectite is smallest among positive factors, and the fractal dimension of the effective pores is the smallest amongst the negative factors.

基于OLI遥感影像的错戳龙错盐湖水深反演研究

传统的水深测量方法是利用测量船上安装的测深设备和定位设备测出水域各点的水深。用遥感方法进行水深反演,基于OLI遥感影像对错戳龙错盐湖进行水深反演研究,确定OLI4波段是研究错戳龙错盐湖遥感水深反演的最佳波段,建立了此盐湖的水深遥感模型。经过对遥感数据和实测点数据的回归分析,建立了拟合方程。根据拟合方程对水深进行反演,反演结果与实测结果基本一致,从而证明了遥感测水深方法的快速有效性,弥补了传统实测水深方法的不足。

Prediction of water table depths under soil water-groundwater interaction and stream water conveyance

Water table over an arid region can be elevated to a critical level to sustain terrestrial ecosystem along the natural channel by the stream water conveyance. Estimation of water table depth and soil moisture on river channel profile may be reduced to a two-dimensional moving boundary problem with soil water-groundwater interaction. The two-dimensional soil water flow with stream water transferred is divided into an unsaturated vertical soil water flow and a horizontal groundwater flow. Therefore, a prediction model scheme for water table depths under the interaction between soil water and groundwater with stream water transferred is presented, which includes a vertical soil water movement model, a horizontal groundwater movement model, and an interface model. The synthetic experiments are conducted to test the sensitivities of the river elevation, horizontal conductivity, and surface flux, and the results from the experiments show the robustness of the proposed scheme under different conditions. The groundwater horizontal conductivity of the proposed scheme is also calibrated by SCE-UA method and validated by data collected at the Yingsu section in the lower reaches of the Tarim River, which shows that the model can reasonably simulate the water table depths.

End Effect on the Twin-Wire Depth Probe

The end effect on the output voltage of a twin-wire depth probe was investigated both theoretically and ex- perimentally.It was found that the contribution of the end of the probe to the output voltage depends upon the distance between the boundary and the end of the probe and the geometrical configuration of the probe. By mounting a piece of plate to the end of the electrodes,the end effect can be reduced.However,the size of the plate required to eliminate completely this effect is much larger than that usually mounted on commercially available probes.Comparison between theoretical and experimental results was made.Reasonable agreement was obtained.