The application of a Grey Markov Model to forecasting annual maximum water levels at hydrological stations

Compared with traditional real-time forecasting,this paper proposes a Grey Markov Model(GMM) to forecast the maximum water levels at hydrological stations in the estuary area.The GMM combines the Grey System and Markov theory into a higher precision model.The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values,and thus gives forecast results involving two aspects of information.The procedure for forecasting annul maximum water levels with the GMM contains five main steps:1) establish the GM(1,1) model based on the data series;2) estimate the trend values;3) establish a Markov Model based on relative error series;4) modify the relative errors caused in step 2,and then obtain the relative errors of the second order estimation;5) compare the results with measured data and estimate the accuracy.The historical water level records(from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin,China are utilized to calibrate and verify the proposed model according to the above steps.Every 25 years’ data are regarded as a hydro-sequence.Eight groups of simulated results show reasonable agreement between the predicted values and the measured data.The GMM is also applied to the 10 other hydrological stations in the same estuary.The forecast results for all of the hydrological stations are good or acceptable.The feasibility and effectiveness of this new forecasting model have been proved in this paper.     

Pollution Source Investigation and Water Quality Management in the Carp Lake Watershed,Taiwan

In this study, a full survey of pollutant sources and water quality was conducted, followed by the application of a water quality model (Water Quality Analysis Simulation Program, WASP) to establish strategies of water quality control in Carp Lake, Taiwan. Results of the field investigation show that both point and non‐point source (NPS) pollutants were responsible for the poor water quality. The contributions of biochemical oxygen demand (BOD) from point source and NPS pollution were 45.9 and 55.1%, respectively. About 80% of total phosphorus (TP) were contributed by NPS. Additionally, point source and NPS pollution discharged 55.5 and 44.5% of NH₃–N load, respectively. The Carlson's Trophic State Index ranged from 61.9 to 69.2 showing serious eutrophic problems in Carp Lake. The calculated BOD, NH₃–N, and TP carrying capacity were approximately 2.8, 0.42, and 0.15 kg per day, respectively. However, the current pollutant loadings are approximately 3.0–5.5 times the calculated carrying capacity. With the help of the calibrated WASP model, remedial strategies for the lake water from short‐term to long‐term were developed. The completion of the small local sewer system to remove 80% of the point source pollution can serve as a short‐term goal while 40–60% of NPS removal by natural treatment systems may serve as a mid‐term goal. Furthermore, 80% of both source point and NPS pollution removal can be considered as a long‐term strategy. Results of heavy metal analysis show that the enriched sediment would be safe for agricultural applications.     

黔南坳陷及邻区盆地演化和海相沉积的后期改造

黔南坳陷是扬子克拉通内由3组不同方向的断裂围限的一个相对稳定的区块。分4个阶段（新元古代,早古生代,晚古生代—三叠纪,侏罗纪—古近纪）重塑了贵州南部及邻区与周边造山作用耦合的盆地演化。广西运动形成北东向构造,是海相沉积建造阶段中的一次重要改造。印支运动使贵阳—镇远断裂和紫云—罗甸断裂反转,奠定了其成为黔南坳陷的北界和西南界断裂的基础。中侏罗世后的逆掩—冲断可分为两期：早期称燕山运动,以北东走向的断裂向北西逆冲和扩展为特征;晚期称燕山末期—喜马拉雅运动,区域上表现为北北东走向的断裂向南东东逆冲,铜仁—三都断裂成为黔南坳陷的东界,印支运动形成的近南北向—北北东向断层向西（偏北）逆冲,构成铜仁—三都断裂的背冲构造。近南北向断层上盘发育的开阔背斜是黔南坳陷内海相油气勘探的最有利靶区。     

填充墙对框架结构侧移及层间位移角影响分析

为了研究填充墙对框架结构侧移和层间侧移角的影响特点,给结构设计提供参考和建议,建立了29个带填充墙的框架结构有限元分析模型,输入3种不同的地震波进行了时程分析。填充墙体对框架结构抗侧移大小和层间侧移角的影响不容忽略,影响其大小的因素主要有填充墙体材料、数量、位置以及计算时地震波的选用。为避免由于填充墙体布置不当造成所谓的"薄弱层",建议本层填充墙体数量不得小于其上部楼层的60%。最后,给出了考虑填充墙体作用的结构刚度计算公式。     

多伦县沙质草原植被的变化趋势分析

在多伦县1984年草原普查资料的基础上,2001年又在28个样点上进行了较详尽的野外考察,比较了相隔17a的草原植被变化。结果表明:潜在沙漠化土地的面积占有相当大的比例;中度、重度退化的比例从50%又有了扩大的趋势,这说明多伦县沙漠化的潜在隐患十分严重;近年来实施的草原保护起到一定的作用,表现在一些退化的样点有了恢复,最典型的例子就是黑山嘴乡胜利村(沙质栗钙土,冷蒿+寸草苔+杂类草,重度退化)沙质草原中的冷蒿群落在封育保护下已经恢复为以大针茅为建群种的群落;而不合理的利用,继续使一些样点上的群落退化。总的趋势仍是局部好转,总体恶化;挖掘和开垦则具有剧烈性的破坏作用,植被表面形成的"破口"在风蚀、水蚀的作用下,沙漠化的进程将会迅速发展。     

碳酸盐岩破裂过程中管道—裂隙水非线性流动特性试验研究

本文聚焦碳酸盐岩微观渗流特性与破裂机制的研究,开展了岩石破裂过程中管道-裂隙水流动可视化试验,基于岩石块体尺度试验结果定量分析管道流体向裂隙流体过渡的流态演化过程,研究多级荷载对管道-裂隙水流动特性的影响。试验结果表明:碳酸盐岩流态稳定性与破裂状态相关,管壁破坏初期管道流主要以层流为主,局部管壁劈裂造成管道流体时域性流态交替,管道流体向裂隙流体转变的前兆特征主要表现为过渡流态临界转换点。碳酸盐岩破裂过程中管道流体向裂隙流体过渡过程具有分数演化特征,分数指数能够定量刻画管流和裂隙流的临界过渡过程。      

哈尔滨荒山岩芯重矿物特征对松花江第四纪水系演化的指示

松花江水系演化研究对于理解该区域的构造-气候-地貌演化具有重要意义,但其研究相对较为薄弱,特别是对于第四纪松花江中上游流向是否存在反转,一直存在争论,也没有确切的证据。河流沉积物是河流地质过程的产物,是研究水系演化的重要地质档案。对哈尔滨荒山岩芯(深度101.11 m,底界年龄1.68~1.70 Ma)沉积物进行了古地磁、磁化率和重矿物分析,结果表明:岩芯62.3 m(0.94 Ma)深度的上、下地层的磁化率和重矿物特征存在明显不同。62.3 m以下地层的磁化率极低(甚至为0),且重矿物特征和依兰方向的河流相近;而62.3 m以上地层的磁化率突然增大,并呈现出周期性的高低变化,重矿物特征与松原方向的现代河流相似。磁化率和重矿物组合特征反映的沉积物物源变化指示了松花江中上游水系的反转。早更新世早期,松花江肇源-依兰段的水流从依兰方向向西注入松嫩湖盆;早更新世中晚期,佳依分水岭不断抬升,三江平原和松嫩平原不断下降,导致分水岭两侧河流溯源侵蚀加剧;在0.94 Ma B.P.,佳依分水岭被切穿,松花江水流发生反转,自西向东流经佳依峡谷进入三江平原。     

碎屑岩储集层成岩作用研究进展与热点问题讨论

近10年来, 碎屑岩储集层成岩作用研究发展迅速, 总结国内外成岩作用研究进展、前沿研究热点和关键问题, 具有重要的学术探索意义。在归纳前人研究成果与认识基础上, 结合国内外典型研究实例, 讨论了近年来碎屑岩储集层成岩作用研究进展以及未来研究热点或发展趋势。认为成岩作用研究在物源对砂岩类型及其成岩演化路径的制约, 流体-岩石相互作用及其产物、热动力学与超压背景对成岩作用与孔隙发育的影响, 油气充注成藏过程与储集层低渗-致密化时序等研究方面取得了长足进展, 正在向将微观尺度成岩作用研究与盆地流体、盆地动力学与热动力学过程等宏观大尺度背景相结合的由源到汇的沉积作用过程、埋藏、烃类成熟与油气充注成藏、构造演化与流体活动、流体-岩石相互作用的成岩作用系统及其时空动态及定量演变机制研究方向发展。本文旨在抛砖引玉, 与业内相关领域的专家学者和同行一起, 在成岩作用研究精细程度、研究深度与广度、最先进的分析测试技术与方法之应用、以及多学科交叉融合方面共同努力, 以期推动中国碎屑岩储集层成岩作用研究的进程。     

隧道工程横向贯通误差的影响因素及其误差分析

影响隧道贯通误差的因素主要有洞内起始方位角、测角精度和测边精度,本文分析起始方位角、测边、测角对隧道贯通误差的影响,得到曲线型、直伸型两种隧道的公式,尤其是分析不同长度、不同精度、不同导线边长条件下横向贯通误差的变化,得出一定规律来指导实践。     

A stochastic optimization model based on adaptive feedback correction process and surrogate model uncertainty for DNAPL-contaminated groundwater remediation design

A stochastic optimization model based on an adaptive feedback correction process and surrogate model uncertainty was proposed and applied for remediation strategy design at a dense non-aqueous phase liquids (DNAPL)-contaminated groundwater site. One hundred initial training samples were obtained using the Latin hypercube sampling method. A surrogate model of a multiphase flow simulation model was constructed based on these samples employing the self-adaptive particle swarm optimization kriging (SAPSOKRG) method. An optimization model was built, using the SAPSOKRG surrogate model as a constraint. Then, an adaptive feedback correction process was designed and applied to iteratively update the training samples, surrogate model, and optimization model. Results showed that the training samples, the surrogate model, and the optimization model were effectively ameliorated. However, the surrogate model is an approximation of the simulation model, and some degree of uncertainty exists even though the surrogate model was ameliorated. Therefore, residuals between the surrogate model and the simulation model were calculated, and an uncertainty analysis was conducted. Based on the uncertainty analysis results, a stochastic optimization model was constructed and solved to obtain optimal remediation strategies at different confidence levels (60, 70, 80, 90, 95%) and under different remediation objectives (average DNAPL removal rate ≥?70,?≥?75,?≥?80,?≥?85,?≥?90%). The optimization results demonstrated that the higher the confidence level and remediation objective, the more expensive was remediation. Therefore, decision makers can weigh remediation costs, confidence levels, and remediation objectives to make an informed choice. This also allows decision makers to determine the reliability of a selected strategy and provides a new tool for DNAPL-contaminated groundwater remediation design.