长江口南汇东滩水动力条件变化的数值预测

南汇东滩紧邻长江口主要排沙通道南槽而成为泥沙沉降的一个重要部位,为促淤围垦提供了有利的滩地和来沙条件,是上海市规划围垦的重点区域。目前上海已在南汇东滩开始实施围垦工程,围垦工程改变了长江口南汇岸线,也改变了南汇东滩的水动力条件。为了解围垦工程实施后水动力条件的变化,采用二维潮流数学模型模拟南汇东滩促淤围垦工程实施前后流场的变化,探讨围垦工程对邻近水域水动力产生的影响,为预测圈围工程实施后南汇东滩变化提供水动力学依据。     

上海南汇东滩(五期)促淤圈围岩土工程勘察实例分析

上海海岸带位于长江三角洲的前缘。由于长江每年携带大量泥沙,在潮汐动水力作用下,使海岸不断向外伸涨成滩涂。随着上海土地资源的紧缺,开发与利用滩涂,成为上海的当务之急。目前在卢潮港等地正在对滩涂兴起大规模的促淤圈围,而圈围前期的岩土工程勘察尤其重要。对圈围场地的工程地质条件,对围堤的稳定及沉降;对吹填沙源均需进行分析评价。该文对南汇东滩圈围场地的岩土工程地质勘察进行了总结。     

近三十年长江口横沙岛潮滩湿地地貌演变对河口工程的响应

由于人类活动的不断加剧和入海泥沙的日益减少,我国部分河口潮滩湿地已面临严重的侵蚀退化风险,给沿岸城市发展带来巨大威胁,实现河口潮滩湿地的科学管理和合理利用极为紧迫。本研究利用1990—2017年多期长江口深水航道北导堤工程与横沙岛成陆-促淤工程前后区域海图地形数据,使用ArcGIS地理配准、等深线数字化、数字高程模型建立和叠加分析等功能分析长江口横沙岛潮滩湿地地貌、等深线形态与地形冲刷-淤积厚度的时空变化过程。研究结果表明,长江口深水航道北导堤工程与横沙岛成陆-促淤工程的实施,改变了横沙岛潮滩湿地周边水域的水文泥沙动力条件,使得地貌冲淤时空特征发生变化：1）深水航道北导堤工程与横沙岛成陆-促淤工程的实施极大地推动了特征等深线的向外延伸,其中0、2和5 m等深线包络面积年均最大增长率（2009—2013年）分别是工程前（1990—1998年）的42.13、280.73和235.65倍,0~1、1~2、2~3、3~4及4~5 m等深线包络体积整体呈现1990—1998年、1998—2009年、2009—2013年增加,2013—2017年较为明显减少,潮滩湿地"长高不长大"的趋势;2）冲刷-淤积频率特征表现为工程前微淤（1990—1998年）、工程后微淤（1998—2009年）、淤积增加明显（2009—2013年）及微冲（2013—2017年）,长江入海泥沙通量的减少对2 m等深线以深区域的潮滩发育可能产生一定影响。     

动力排水固结法加固浦东机场促淤地基试验研究

基于浦东国际机场快件处理中心促淤场地的加固处理实践,介绍采用动力排水固结法处理促淤饱和软粘土地基的工艺对吹填粉细砂上试夯区的试验研究,结果表明采取低能量“少击多遍”的强夯施工工艺,并辅以竖向塑料排水板的方法来加固处理饱和促淤软粘土是可行的,促淤地基的力学性能和变形性能显著提高,并实现了用吹填粉细砂代替中粗砂作为强夯垫层,大大降低了工程成本。通过对大面积强夯施工处理效果的检测表明,动力排水固结法加固处理促淤地基效果明显。     

基于遥感和GIS的上海市滩涂湿地资源近期变化分析

利用多期Landsat-5 TM影像,结合植被分带信息、地物波谱特征和实地调查数据,提取上海地区滩涂湿地分布及其覆盖信息;在ArcGIS软件支持下,综合多期遥感影像解译结果和相应时段的水下地形信息,对上海市滩涂湿地空间分布及其变化进行分析。结果表明,近15年来上海市滩涂围垦量在不断增加;尽管滩涂湿地仍在继续淤涨,但淤涨速度明显减缓,且慢于围垦速度,这导致中高潮滩涂面积不断减少。     

长江口北支河槽容积变化特征的定量分析

北支河槽容积变化是北支河道演变趋势在定量上的直接表现,河道边界条件和河床泥沙运动是影响河槽容积变化的主要因素。收集1986—2013年长江口北支河道年实测地形资料,利用GIS技术建立不同时期水下数字高程模型,进行北支河槽容积变化和河床冲淤变化特征分析。结果表明,北支岸线圈围和泥沙淤积导致了1986年以来河槽容积萎缩。北支河槽0m线以下容积共减少约7.110亿m3,岸线圈围引起河槽容积减少4.000亿m3,占比56.3%;泥沙淤积引起的河槽容积减少3.110亿m3,占比43.7%。具体而言,北支上段河槽容积萎缩主要是泥沙淤积所致,其航道开发综合利用应遵循上段的泥沙运动规律特点;中段则是边滩圈围和沙洲并岸引起,边界调整后束流作用加强,河床冲刷,断面形态调整后水深条件更加有利于中段的航道利用开发;下段是泥沙淤积和边滩圈围共同影响所致,泥沙淤积影响略大,但下段沿北岸-5m深槽始终存在且稳定,具备航道开发利用的河势基础,且南侧河道边界仍具有可圈围的余地。     

长江口12.5 m深水航道回淤年际变化及成因

长江口12.5 m深水航道回淤量大,影响因素复杂。利用2011-2017年长江口航道水下地形、水文测验和航道回淤等系列资料,研究了12.5 m深水航道回淤的年际变化过程和原因。结果表明:① 12.5 m深水航道回淤总体呈现稳中下降的变化特征。②南港-圆圆沙段因航道滩槽高差的缩小和上游底沙输沙量的减少,回淤呈逐年减少态势。③北槽段因南坝田挡沙堤加高工程的实施和台风影响偏弱,2016-2017年回淤较此前有所减少;径流影响北槽最大浑浊带的发育部位,进而影响北槽航道回淤的部位,2016-2017年长江口径流量偏大是北槽航道主要回淤部位较往年偏下的主要原因。④流域减沙对12.5 m深水航道回淤的影响已开始显现。未来受其影响,南港-圆圆沙航道回淤有望进一步下降并维持较低量值,北槽航道回淤有望维持稳中下降态势。     

长江口岸带冲淤及后备土地资源的沉降效应——以上海崇明东滩为例

长江口入海泥沙的淤积是上海后备土地资源的重要来源，分析岸带冲淤的演变．有助于对岸带经济圈特别是围垦促淤地区因经济工程活动引发的地面沉降问题的剖析。本文以上海崇明东滩为例，分析30年来的冲淤变化及未来趋势，并据此对新近沉积土的地面沉降效应作简要阐述。     

碎石盲沟排水对黄河放淤固堤工程淤背体固结影响

为了分析排水措施对淤背体固结特性影响,以黄河山东某堤段为研究对象,数值模拟研究在淤区设置碎石盲沟排水方案,淤背施工过程中以及施工完成后放淤固堤工程孔隙水压力消散过程,探讨淤背体排水固结规律。研究结果表明,与无排水方案相比,该排水方案可以加速淤背土体固结,减小水分对黄河大堤堤背的渗入,降低围堤内的浸润线。在与试验区相似的施工工况条件下,建议3m左右淤土厚度布置一层排水盲沟,排水效果较好。数值计算结果与实际情况相吻合,可为黄河放淤固堤工程加快淤背体排水提供参考。     

钻孔灌注桩事故防范与桩基质量控制

在钻孔灌注桩施工过程中，对经常发生的工程事故，介绍了几种防范措施和钻孔灌注桩施工中的重要指标桩底回淤量的控制方法，通过防范工程事故、控制回淤量，从而达到提高桩基质量的目的。     

Groundwater quality as a geoindicator of organochlorine pesticide contamination after pesticide tomb reclamation: a case study of Franciszkowo, northwestern Poland

The need of surface soil removal during reclamation of the former underground landfills makes environmental monitoring difficult to perform. Environmental quality assessment after reclamation is very important because it provides information about: (1) the efficiency of remediation, (2) the rate of biodegradation of contaminants which were not removed during reclamation works and (3) the possible migration of contaminants from soil and permeable host rocks to surface waters and groundwaters. The concept of geoindicators, which was introduced to facilitate the assessment of environmental changes, can help assess environmental quality at sites previously subjected to reclamation. The groundwater quality is usually used as a geoindicator of inorganic contaminants. This concept was applied to find changes in organochlorine pesticide concentrations in groundwaters after toxic pesticide burial ground reclamation. The aim of this study was to monitor the concentrations of organochlorine pesticides and their metabolites in groundwaters at the former pesticide landfill site after its remediation. The study showed that very high concentrations of organochlorine pesticides and their metabolites in a contaminated soil had a small influence on pesticide concentrations in groundwaters and that this influence decreased in time. It has been 2 years since reclamation of the landfill took place, and the concentrations of organochlorine pesticides in groundwaters dropped to acceptable levels within the current environmental quality standards.     

Characteristics of Singapore Marine Clay at Changi

Singapore marine clay at Changi is a quartenary deposit that lies within valleys cut in the Old Alluvium. It is locally known as Kallang formation. The pre-reclamation site characterization and laboratory testing was carried out by conducting marine sampling boreholes, in situ dissipation tests and field vane test. In situ dissipation tests were conducted with the piezocone, flat dilatometer, self-boring pressuremeter and BAT permeameter. The purpose of the site characterization was to determine the consolidation characteristics, strength characteristics, stratigraphy, and mineralogy of Singapore marine clay. The consolidation properties of marine clay are required prior to land reclamation activities in order to predict the magnitude and rates of settlement with the expected fill load and future service load as well as for the design of soil improvement works. The shear strength properties are required for slope stability analyses during reclamation and for the stability analyses of shore protection works. Clay mineralogy tests and photographic identification of the marine clay was carried out to determine the mineralogical properties and to visually record the marine clay colour and texture.     

巨石、中粗砂填海区风动潜孔锤引孔钻进工艺应用的研究

通过成功地解决深圳市好湾电厂（二期）基础工程H型桩沉入困难问题，使用各种风动潜孔锤在巨石、中粗砂填海区进行了引孔钻进工艺的试验研究及应用，对风动潜孔锤钻进工艺及其机具的使用作了进一步的分析研究，提出了风动潜孔锤使用过程中工艺方面的改进措施。     

淮北海孜煤矿采煤塌陷区煤矸石充填复垦条件分析

为了增加塌陷区耕地资源,有效地提高土地利用率,减少环境污染,本文通过对海孜煤矿塌陷区进行实地勘查,室内测试和实验,分析塌陷区煤矸石充填复垦条件。分析结果表明:塌陷区的地形地貌条件有利于土地复垦工程的实施,较高的地下水位可以为重构土壤提供充足的水分;塌陷区塌陷深度小,且绝大部分塌陷区已达到稳沉状态,有益于煤矸石充填复垦;大量的煤矸石为充填复垦提供了充足的物质基础,煤矸石中有害元素含量低,复垦后不会对地下水和土壤造成显著的污染,且煤矸石的块度组分有利于水分的保持和上移。     

Ground Investigations for Changi East Reclamation Projects

Geotechnical ground investigation is important in all construction works particularly, land reclamation projects. The Changi East reclamation project is a mega project that involves creation of land space as large as 3,000 hectares in multiple phases between 1991 and 2005. Ground investigation plays a critical role in the Changi project which involved substantial amount of ground improvement works after reclamation by sand filling. One important aspect of the investigation was to evaluate the geotechnical characteristics of the underlying compressible soils beneath the original seabed for the selection of suitable methods of ground improvement. The other important aspect of the investigation was to characterize and verify the compactness of the reclaimed sand fill. Many types of in situ tests were extensively used in the project. The field vane shear test provides correlations between the undrained shear strength and depth for the upper and the lower marine clay strata in the Northern part and the Southern Part of the reclaimed site. Combined with laboratory undrained shear strength tests, the field vane strength profiles allow the derivation of the undrained shear strength over effective stress ratios for the upper and the lower marine clays. In addition, results from three other in situ tests, the piezocone cone penetration test, the flat dilatometer test, and the self boring pressuremeter test provided useful verification of these correlations. A field-performance based method of assessing degree of consolidation in the underlying clay was developed by combining field monitoring, laboratory testing and conventional as well as specialized in situ testing. An effective use of in situ testing methods for assessment, the outcome of ground improvement and for fill quality control in the densification of granular soils is illustrated with field observation data collected at the project site.     

对目前煤炭资源勘查与开发利用中存在的一些问题的思考

煤炭资源勘查和开发利用中,存在着一些值得思考与探讨的问题,如资源储量划分、勘查区境界的依据、资源分类与勘查程度的关系、回采率问题、共伴生矿床的勘查、煤层气勘查与瓦斯抽放、水文地质工程地质及开采技术条件勘查、采矿废弃物资源化、基础性地质工作的管理等。针对上述问题,结合煤炭资源勘查实践,提出了相应的建议。     

肥城煤田白庄煤矿土地复垦适宜性评价方法探讨

土地复垦适宜性评价是土地复垦方案编制过程中至关重要的环节,该文以白庄煤矿为例,在分析土地复垦相关因素的前提下,遵循一定的评价原则,制定了土地复垦适宜性评价的方法和步骤,并最终确定了复垦区各单元的复垦方向,对同类地区土地复垦方案的编制具有一定的参考价值。     

Coastal Reclamation and Saltmarsh Carbon Budget: Advances and Prospects

As an important carbon pool and fragile eco-system of earth system, more and more coastal saltmarshes have been reclaimed for releasing population pressure and promoting food safety and economic development, especially in developing countries. During reclamation, original soil carbon cycling pattern and pathway in saltmarshs would be changed, which furthermore could change global carbon budget. In this study, a great amounts of literature and data were summerized to generalize the changes of soil organic carbon, carbon sequestration rate and carbon flux in three main kinds of saltmarshes (Mangrove saltmarsh, Estuary saltmarsh and coastal saltmarsh) during reclamation. The results are as shown: ①The conclusions collected from Europe and America are not suitable to eastern Asia’s coast and more attention should be paid to eastern Asia’s coastal reclamation; ②Mangrove saltmarshes have higher Soil Organic Carbon (SOC) and carbon sequestration rate, followed by estuary saltmarshes and coastal saltmarshes. Soil clay, aggregate, burial rate usually have positive effect on SOC sequestration in coastal areas. Flood frequency, salinity and underground water level generally have negative effect on it. After reclamation, coastal SOC first shows a decrease followed by an increase. Nearly 30 years of reclamation is the turning point where paddy fields can significantly promote SOC; ③CH₄ and CO₂ are the main ways of carbon emission in coastal areas of which CO₂ flux usually is the largest. Mangrove saltmarshes’ carbon emissions are the highest. In natural sites, the carbon emissions in Spartina alterniflora Loisel. and Phragmites australis are higher than those in bare flat areas. Carbon fluxes in flood tide usually are lower than those in other periods. Otherwise, carbon fluxes in natural saltmarshes are far lower than those in reclamation zones, especially upland tillage zones. The results acquired from field monitoring, saltmarshes are the carbon sinks and become the carbon sources when reclamation activities happen. Finally, three main aspects of coastal study were given as follows: much more attention should be paid to carbon budget inventory in saltmarshes; the effect of reclamation activity (i.e., anthropogenic activity, tillage practice, land use, etc.) on carbon cycling in ocean-inland system; the study of land use and reclamation process simulation and its impact on carbon cycling in coastal zone should be strengthened.     

编制矿山土地复垦方案值得注意的几个问题

在编制矿山土地复垦方案过程中,要认真调查、了解和掌握矿山的自然环境条件及矿山开采历史与现状,以及拟开采布局和复垦资源情况,才能确定合理的复垦方向、制定复垦目标,编制出质量较高、可操作性强的矿山土地复垦方案。     

天津滨海新区围海造陆对沿海低地浅层地下水环境的影响

天津滨海新区被提到国家总体发展战略后,随着经济持续发展、城市化进程不断加速及产业转移,进行了大规模围海造陆,在拓展土地空间的同时,也造成了相当多的环境问题。利用滨海新区由陆到海的3条水文地质剖面获取的地下水动态变化监测数据和土壤含盐量测试结果,开展了围海造陆对沿海低地浅层地下水环境的影响研究。结果显示:1受围海造陆影响,对应的沿海低地浅层水位已经出现由陆到海逐渐增高的现象,造成地下水位反向倾斜,阻碍了地下水径流和排泄;2由陆到海浅表土壤全盐量出现逐渐增高的特征,在浅层地下水反向径流作用下,东部区域大量的盐分将被携带至沿海低地,使沿海低地盐渍化程度加重,严重影响到湿地保护和生态建设;3围海造陆对海岸带生态环境的影响是一个长期缓慢的过程,应持续监测近岸海域和陆域沿海低地生态环境的变化情况,以便提出合理的修复建议。