In-Situ Observation of Fluid Mud in the North Passage of Yangtze Estuary, China

Observations of fluid mud were made in the lower North Passage of the Yangtze Estuary in February 2000, on 10～11 August 2000, on 30～31 August 2000 (after two strong typhoons), on 21～24 August 2000 (neap tide) and on 3～6 September 2000 (mean tide) respectively. In situ data show that the fluid mud in this area consists of fine cohesive sediment (median size 7.23 μm). The formation and movement of fluid mud varied during the neap-spring and flood-ebb tidal cycle. Observations suggest that fluid mud phenomena in this area may be categorised in a three-fold manner as slack water, storm and saltwedge features. The thickness of the fluid mud layer of slack water during the neap tide ranged from 0.2 to 0.96 m, whereas during the mean tide, the thickness ranged from 0.17 to 0.73 m, and the thickness of the fluid mud layer was larger during slack water than at the flood peak. Shoals cover an area of 800 km2 with a water depth smaller than 5 m. Erosion of these extensive intertidal mudflats due to storm action provides an abundant sediment source. This is particularly significant in this estuary when the tidal level is lower than 5 m. The lower North Passage is a typical zone of saltwater wedging, so the saltwedge fluid mud has the most extensive spatial range in the estuary.

Modeling Near-Field Impulsive Waves Generated by Deformable Landslide Using the HBP Model Based on the SPH Method

Landslide-generated impulsive waves(LGWs)in reservoir areas can seriously threaten waterway safety as well as hu-man life and properties around the two side slopes.The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics,such as wave amplitude and run-up.However,near-field LGW involves complicated fluid-solid interactions.Furthermore,the wave characteristics are closely related to various aspects,including the geometry and physical features of the slide,river,and body of water.However,the empirical or analytical methods used for rough estimation cannot derive accurate results,especially for deformable landslides,due to their significant geometry changes during the sliding process.In this study,the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics(SPH)based on multi-phase flow.The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou(HBP)-based nonNewtonian rheology model.The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved.In this study,an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration.The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics,thus indicating the applicability and accuracy of the proposed method.Finally,the effects of the HBP model’s rheological parameters on the landslide dynamics and near-field wave characteristics are discussed,providing a parameter calibration method along with sug-gestions for further applications.

Sheltering effect of punched steel plate sand fences for controlling blown sand hazards along the Golmud-Korla Railway:Field observation and numerical simulation studies

Sand fences made of punched steel plate(PSP)have recently been applied to control wind-blown sand in desertified and Gobi areas due to their strong wind resistance and convenient in situ construction.However,few studies have assessed the protective effect of PSP sand fences,especially through field observations.This study analyzes the effects of double-row PSP sand fences on wind and sand resistance using field observations and a computational fluid dynamics(CFD)numerical simulation.The results of field observations showed that the average windproof efficiencies of the first-row and second-row sand fences were 79.8%and 70.8%,respectively.Moreover,the average windproof efficiencies of the numerical simulation behind the first-row and second-row sand fences were 89.8%and 81.1%,respectively.The sand-resistance efficiency of the double-row PSP sand fences was 65.4%.Sand deposition occurred close to the first-row sand fence;however,there was relatively little sand on the leeward side of the second-row sand fence.The length of sand accumulation near PSP sand fences obtained by numerical simulation was basically consistent with that through field observations,indicating that field observations combined with numerical simulation can provide insight into the complex wind-blown sand field over PSP sand fences.This study indicates that the protection efficiency of the double-row PSP sand fences is sufficient for effective control of sand hazards associated with extremely strong wind in the Gobi areas.The output of this work is expected to improve the future application of PSP sand fences.

广东地震地下流体监测网质量与效能分析

依据流体学科相关评价标准,从广东地下流体观测网观测环境、观测仪器、观测质量和预测应用方面着手,结合地下流体学科台网中心提供的台站网运行监控和质量监控情况,对地下流体观测网每个观测站的观测环境、仪器的运行情况、观测仪器产出的数据的质量及其预测应用情况进行了评估。结果显示,观测站观测环境满足二类台站居多;观测数据运行率为优秀者占比:水位、水温和氡各为77.8%、63.6%和100.0%;流体仪器数据完整率全部为优秀;预测应用效能井水位和氡均为良好,水温有88.9%为良好。通过评估,较全面地分析了广东地下流体观测网存在的问题,并针对存在的不足提出改进措施及建议。

2018年9月8日墨江5.9级地震云南普洱大寨流体异常特征及机理

文中梳理了2004年以来普洱大寨井连续观测的水化学离子和井-含水层渗透性异常特征。研究发现,在观测井周边250km范围内5.5级以上地震发生前,多次出现过可重复、可类比的异常变化,对地震具有较好的异常指示和预测意义。但相比以往震例,墨江5.9级地震发生前,无论是化学离子还是物理参数均出现了观测以来幅度最大的变化,异常状态较以往强烈很多,但发震的震级只有5.9级。为了研究这一现象产生的原因和机理,文中尝试从区域深部物质活动和区域应力水平2个方面对墨江5.9级地震前的异常演化过程开展讨论,得到以下认识:墨江5.9级地震前,流体异常整体呈现出较为显著的从深部到浅部、从背景到短期微观异常再到临震宏观异常的演化过程;墨江5.9级地震前,普洱大寨连续观测的水化学离子浓度异常和井-含水层渗透性的改变是由于区域内垂向剪切应力持续增强引起的含水层受挤压,从而形成了垂向的流体补给,最终引起不同含水层水体发生交替混合而产生的结果;本次异常形成初期还伴随深部物质剧烈活动的现象,较为显著的由深部到浅部的耦合作用过程可能是导致墨江5.9级地震前出现自观测以来地下流体异常幅度最显著的原因。因此,流体活动从深部开始,随着区域应力不断积累,不断向地表传递的演变过程是墨江5.9级地震前流体异常演化的本质特征;区域应力的作用方式和深部物质活动程度不同,是引起墨江5.9级地震前异常特征与研究区其他历史震例前明显不同的根本原因。文中研究为全面认识普洱大寨井地下流体异常的预测意义和地震前流体异常的深浅耦合演化过程提供了一定参考。

芍药甘草汤加味治疗儿童功能性便秘肠燥津亏证临床观察

目的:观察芍药甘草汤加味治疗儿童功能性便秘肠燥津亏证的疗效。方法:138例随机分为观察组70例和对照组68例。观察组予以芍药甘草汤加味,对照组予以乳果糖溶液。结果:观察组疾病总有效率为88.57%(62/70),中医证候总有效率为92.86%(65/70),疾病复发率为22.92%(11/48);对照组疾病总有效率为77.94%(53/68),中医证候总有效率为80.88%(55/68),疾病复发率为52.94%(9/17)。两组比较差异均有统计学意义(P<0.05)。结论:芍药甘草汤加味治疗功能性便秘肠燥津亏证疗效较好。

安徽省流体观测井水温测项观测效能评价与分析

水温观测数据主要反映地热场的变化,数据产品服务于安徽省及邻区中、短、临地震预测与科学研究。全面梳理和分析安徽省地下流体水温测项的观测效能,一方面为改进安徽省水温测项的观测技术、提升观测质量提供依据;另一方面为流体异常核实、异常分析和异常性质的判定提供参考,为科学研判安徽及其邻区的震情形势提供科学依据。

公路施工扬尘的传播扩散规律仿真模拟研究

为了解决在公路工程现场进行施工扬尘传播观测实验受环境条件影响严重的问题,采用仿真模拟试验与现场观测实验相结合的方法对公路施工扬尘的传播扩散规律进行研究。首先,根据依托工程土体取样参数与风力条件,通过计算流体力学(CFD)软件构建了施工扬尘仿真模型,分别模拟了风速为5 m·s^(-1)与3 m·s^(-1)下的车辆引起施工扬尘的传播扩散情况;然后,在公路工程现场通过仪器观测了工程车辆行驶引起的施工扬尘在长距离传播扩散过程中的浓度值变化情况;最后,通过现场观测实验验证基于CFD构建的施工扬尘仿真模型分析结果的合理性。研究表明:仿真风速为5 m·s^(-1)和3 m·s^(-1)时车辆引起的施工扬尘团传播速度分别为5 m·s^(-1)与2.9 m·s^(-1),在距停车位置45,65,85 m远处扬尘的峰值浓度为分别为228.1,194.2,162.5与515.8,449.9,395.7μg·m^(-3),现场的观测实验结果介于仿真结果之间。基于施工现场土样参数与风力条件构建的公路施工扬尘仿真模型具有较高保真度。

浅埋多煤层开采“两带”高度探测及覆岩力学性能分析

随着煤炭开采强度越来越高,采空区面积越来越大,“两带”高度的探测确定对于煤矿安全高效生产显得越发重要。采用钻孔冲洗液漏失量观测、钻孔水位观测、钻进异常现象观测、彩色钻孔电视观测等多种方法对青龙寺煤矿5^(-2)煤层上覆岩层破坏情况进行探测,综合分析确定青龙寺煤矿5^(-2)煤层综采工作面开采条件下的最大垮落带高度为17.0 m,垮采比为7.4,最大导水裂隙带高度为46.87 m,裂采比为20.4。同时对5^(-2)煤层上覆岩层的岩石力学性质测试并进行分析,将顶板覆岩岩性分为砂岩类岩层和泥岩类岩层两大类,在顶板以上70 m内,砂岩类岩层占比96.14%,自然状态下单轴抗压强度平均为67.82 MPa,覆岩属坚硬类型,具备坚硬顶板的特征。探测及力学分析结果可为青龙寺煤矿后续上行开采提供技术参考。

地震流体观测井防止积水倒灌装置的研究与应用

一些地震流体观测井受周边观测环境的影响,容易在汛期出现降雨积水干扰现象,严重影响观测数据质量,甚至造成数据传感器故障。本文针对天津市滨海地震监测中心站民园井在观测中出现的积水倒灌现象,设计两种可根据观测井孔实际情况“量身定制”的用于防止观测井在降雨积水时出现倒灌的连通装置,并将观测井的最大水位深度、井口形状、周围空间环境和可能出现的最大积水深度等因素与装置规格建立理论转换关系式。实际应用情况表明,该装置可有效保护流体观测设备,减少观测数据干扰,提高观测数据的连续率和完整率,同时具备很强的适应能力,易于在流体观测井中推广,以解决低洼地区或洪水高发地区观测井的积水倒灌问题,为地震预测预报工作提供连续、完整的观测数据。

The September 16, 2015 Mw 8.3 Illapel, Chile Earthquake： characteristics of tsunami wave from near-field to far-field

On September 16, 2015, an earthquake with magnitude ofMw 8.3 occurred 46 km offshore from Illapel, Chile, generating a 4.4-m local tsunami measured at Coquimbo. In this study, the characteristics of tsunami are presented by a combination of analysis of observations and numerical simulation based on sources of USGS and NOAA. The records of 16 DART buoys in deep water, ten tidal gauges along coasts of near-field, and ten coastal gauges in the far-field are studied by applying Fourier analyses. The numerical simulation based on nonlinear shallow water equations and nested grids is carried out to provide overall tsunami propagation scenarios, and the results match well with the observations in deep water and but not well in coasts closed to the epicenter. Due to the short distance to the epicenter and the shelf resonance of southern Peru and Chile, the maximum amplitude ranged from 0.1 m to 2 m, except for Coquimbo. In deep water, the maximum amplitude of buoys decayed from 9.8 cm to 0.8 cm, suggesting a centimeter-scale Pacific-wide tsunami, while the governing period was 13-17 min and 32 min. Whereas in the far-field coastal region, the tsunami wave amplified to be around 0.2 m to 0.8 m, mostly as a result of run-up effect and resonance from coast reflection. Although the tsunami was relatively moderate in deep water, it still produced non-negligible tsunami hazards in local region and the coasts of farfield.

Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River

Based on field hydrological,microstructural,and shipboard Acoustic Doppler Current Profiler data,we quantified the spatial and temporal variability of turbulent mixing in the near-field Changjiang(Yangtze)River plume.The surface dissipation rate(ε)changed by three orders of magnitude from near-field(10^-4 W/kg)to far-field(10^-7 W/kg)plumes,indicating a decrease with distance from the river mouth.Below the river plume,εchanged with depth to 10^-8 W/kg,and increased to 10^-6 W/kg at the layer where the Taiwan Warm Current(TWC)intruded.Thus,εin the near-field plume showed three layers:surface layer in the river plume,middle layer,and lower TWC layer.In the river plume,the strongestεand turbulent diffusivity(Kz)were greater than 10^-4 W/kg and 10^-2 m^2/s,respectively,during strong ebb tides.A three-orders-of-magnitude change inεand Kz was observed in the tidal cycle.The depth of the halocline changed with tidal cycles,and stratification(N 2)varied by one order of magnitude.Stratification in the TWC layer followed the distribution of the halocline,which is opposite to the dissipation structure.Tidal currents led to intrusion and turbulent mixing in the TWC layer.During ebb tides,εand Kz were as strong as those measured in the river plume,but did not last as long.The structure of the velocity shear was similar to the dissipation rate in both the river plume and TWC layer,whereas the velocity shear in the TWC layer did not match the stratification structure.In the high dissipation rate area,the gradient Richardson number was smaller than the critical value(Ri g<1/4).The Ri g structure was consistent with shear and dissipation distributions,indicating that turbulent mixing in the near-field plume was controlled by a combination of shear induced by the discharged river flow and tidal current.

The S to P convert wave from the bottom of sediment basin in the near-field seismic records

From the near-field records of aftershock of Datong earthquakes in October 1989 and March 1991,an extra phase between P and S arrivals is found. High-precision epicenter location shows that some of these records are obtained with the incidental angle less than the critical angle. This excludes the possibility that the extra wave phase is a refractive wave from ground surface. Particle motion analysis shows that the characteristic of the extra wave is similar to that of wave, so it is possible that the extra phase is an S to P convert wave from the bottom of sediment basin. Suppose a low velocity layer covers a high velocity basement. Successful simulation by the synthetic seismogram confirms that the extra phase is an S-P convert wave from the interface of the basin bottom. Modifying the depth of interface at each ray path to match the waveform, we obtain an interface distribution in space. In this way, a brief bottom image could be shown, and the Datong basin has a 'V' shaped bottom.

Soft Sensor for Inputs and Parameters Using Nonlinear Singular State Observer in Chemical Processes

Chemical processes are usually nonlinear singular systems.In this study,a soft sensor using nonlinear singular state observer is established for unknown inputs and uncertain model parameters in chemical processes,which are augmented as state variables.Based on the observability of the singular system,this paper presents a simplified observability criterion under certain conditions for unknown inputs and uncertain model parameters.When the observability is satisfied,the unknown inputs and the uncertain model parameters are estimated online by the soft sensor using augmented nonlinear singular state observer.The riser reactor of fluid catalytic cracking unit is used as an example for analysis and simulation.With the catalyst circulation rate as the only unknown input without model error,one temperature sensor at the riser reactor outlet will ensure the correct estimation for the catalyst circulation rate.However,when uncertain model parameters also exist,additional temperature sensors must be used to ensure correct estimation for unknown inputs and uncertain model parameters of chemical processes.

利用微水试验方法研究井-含水层水力参数及其与地震的对应关系

准确及时地获取井-含水层系统的水力参数,是当前地震地下水异常识别、异常核实分析面临的关键技术问题。文中基于山西地区8口地下流体观测井,利用微水试验方法估算了各井孔的观测含水层导水系数,对比分析了各井-含水层导水系数及其对井水位同震响应的影响,得到以下认识:1)导水系数大的井孔,同震响应多为震荡型;2)利用微水试验方法可动态获取井-含水层水力参数,捕捉含水层介质状态的细微变化,更准确地解释井水位动态变化;3)水位秒采样观测仪器的普及使用,使得利用微水试验方法测定地下流体含水层介质参数时更为方便实用。

The Co-seismic Response of Underground Fluid in Yunnan to the Nepal MS8.1 Earthquake

In this paper,statistics are taken on the co-seismic response of underground fluid in Yunnan to the Nepal M_S8. 1 earthquake,and the co-seismic response characteristics of the water level and water temperature are analyzed and summarized with the digital data. The results show that the Nepal M_S8. 1 earthquake had greater impact on the Yunnan region,and the macro and micro dynamics of fluids showed significant co-seismic response. The earthquake recording capacity of water level and temperature measurement is significantly higher than that of water radon and water quality to this large earthquake; the maximum amplitude and duration of co-seismic response of water level and water temperature vary greatly in different wells. The changing forms are dominated by fluctuation and step rise in water level,and a rising or falling restoration in water temperature. From the records of the main shock and the maximum strong aftershock,we can see that the greater magnitude of earthquake,the higher ratio of the occurrence of co-seismic response,and in the same well,the larger the response amplitude,as well as the longer the duration. The amplitude and duration of co-seismic response recorded by different instruments in a same well are different. Water temperature co-seismic response almost occurred in wells with water level response,indicating that the well water level and water temperature are closely related in co-seismic response,and the well water temperature seismic response was caused mainly by well water level seismic response.

结合CEEMDAN的改进小波阈值地下水温观测数据去噪方法

提出一种结合自适应噪声完备集合经验模态分解方法(CEEMDAN)的改进小波阈值降噪算法,用于地下水温观测数据的去噪。在利用该方法与传统的去噪方法分别对仿真信号进行降噪后发现,该去噪方法性能更优,并且在对实际采集到的含有噪声及异常突变的地下水温数据进行处理方面,也展现出比传统单一滤波手段更好的效果。

In situ observations of tungsten speciation and partitioning behavior during fluid exsolution from granitic melt

Most economically important tungsten(W)deposits are of magmatic-hydrothermal origin.The species and partitioning of W during fluid exsolution,considered to be the controlling factors for the formation of ore deposits,are thus of great significance to investigate.However,this issue has not been well addressed mainly due to the significant difference in reported partition coefficients(e.g.,from strongly incompatible to strongly compatible)between fluid and melt(D_(W)^(fluid/melt)).Here,we used an in situ Raman spectroscopic approach to describe the W speciation,and to quantitatively determine the Dfluid/melt of individual and total W species in granite melts and coexisting Na2WO4 solutions at elevated temperatures(T;700–800C)and pressures(P;0.35–1.08 GPa).Results show that WO_(4)^(2-)and HWO4are predominant W species,and the fractions of these two species are similar in melt and coexisting fluid.The partitioning behaviors of WO_(4)^(2-)and HWO4are comparable,exhibiting strong enrichment in the fluid.The total DW fluid/melt ranges from 8.6 to 37.1.Specifically,DW fluid/melt decreases with rising T–P,indicating that shallow exsolution favors enrichment of W in evolved fluids.Furthermore,Rayleigh fractionation modeling based on the obtained D_(W)^(fluid/melt)data was used to describe the fluid exsolution processes.Our results strongly support that fluid exsolution can serve as an important mechanism to generate W-rich oreforming fluids.This study also indicates that in situ approach can be used to further investigate the geochemical behavior of ore-forming elements during the magmatic-hydrothermal transition,especially for rare metals associated with granite and pegmatite.

用于气象站的地表气温观测仪器的设计与实验研究

大气科学研究对地表气温观测精度有高达0.1℃甚至0.05℃的需求。然而,现有的地表气温观测仪器受到太阳直接辐射、下垫面反射辐射、长波辐射和散射辐射等影响,辐射误差可达1℃。本文设计了一种基于导流装置的地表气温观测仪器。首先,利用计算流体动力学(Computational Fluid Dynamics,CFD)方法量化该仪器在各种环境条件下的辐射误差;然后,在此基础上,利用极限学习机(Extreme Learning Machine,ELM)方法拟合可针对多变量变化的辐射误差订正方程;最后,为验证该仪器的观测精度,进行了外场比对实验。在实验过程中,以076B型强制通风气温观测仪器的测量值作为温度基准。实验结果表明,该仪器的平均辐射误差和最大辐射误差分别为0.07℃和0.15℃。该仪器辐射误差的实验测量值与订正方程提供的辐射误差订正值之间的平均偏移量、均方根误差和相关系数分别为0.033℃、0.028℃和0.703。

基于CFD与BFGS的四加热湿度传感器设计

针对湿度传感器在高空气象探测时因表面覆盖水凝物引起沾湿误差的问题,提出了一种具有加热冷却功能的四加热湿度传感器。为实现对加热策略的优化设计,将传感器的工作周期分为4个阶段:加热阶段、稳定阶段、冷却阶段和测量阶段。首先,采用计算流体动力学(CFD)方法计算出4个阶段对应的时间;接着,利用拟牛顿法中使用较多的BFGS算法进行数据拟合,得到加热时间和冷却时间的修正公式;最后,以低气压风洞作为实验平台,开展外场喷雾实验进行对比验证。实验结果表明:四加热湿度传感器加热时间的修正值与实验值差值绝对值的平均值为0.112 s,均方根误差为0.133 s;冷却时间的修正值与实验值差值绝对值的平均值为0.801 s,均方根误差为0.959 s。开启加热时,传感器可以减小10%以上的测量误差,由此验证了该方法的可行性。