塑性混凝土咬合桩在临海基坑工程中的应用

以蛇口邮轮中心基坑支护工程为例,研究在临海抛石地基上基坑支护方案的选用。通过现场试验获取施工参数并计算渗透系数,根据结果选择塑性混凝土咬合桩结构方案。介绍塑性混凝土咬合桩的受力特点和计算方法,以及在止水帷幕中的应用,并与实测资料相验证,证明了在抛石地基临海基坑中采用塑性混凝土咬合桩是安全可行的。     

沉箱开孔对平均越浪量的影响

针对开孔沉箱对平均越浪量影响的问题,以国内某港区通用码头工程为基础,对比分析了直立式沉箱和开孔沉箱平均越浪量的多种经验公式计算方法,并和断面物理模型试验结果进行比较。公式计算结果显示,开孔沉箱与不开孔沉箱平均越浪量之比为25%~50%;断面物理模型试验结果显示,沉箱开孔与不开孔时越浪量之比为30%~82%。研究表明开孔沉箱能够有效降低海岸结构物的平均越浪量;国内学者提出的开孔沉箱越浪量计算方法所得结果更加接近物理模型试验结果。     

极地航行法规与准则现状

受全球气候变暖的影响,两极冰融现象日益加剧.北极冰层的大面积融化促进了北极航线的开发,南极的冰雪美景也吸引了越来越多的游客乘船观光.本文针对极地航行的特殊性和挑战性,从极地安全航行和环境保护的角度出发,阐述了现行的极地水域国家相关的法律法规、国际公约、IMO和IACS等国际性组织出台的一系列规则和要求,并分析了IMO强制性《极地水域船舶作业国际规则》对船舶及海上人命安全和极地海洋环境保护的要求.     

海洋生态系统及海岸工程生态影响预测模型研究进展

对海洋生态系统的研究已形成了以实验观测为基础、建立生态模型的方法。文章对已有的海洋生态模型研究成果进行了归纳总结,认为初级生产力模型是纯生态模型的主要发展方向,综合考虑物理生化作用的生态系统动力学模型将是未来海洋生态研究的必然趋势。同时,由于我国大规模海岸工程建设对近岸海域生态系统造成了较大影响,而相关的生态影响预测模型研究较少,为有效预测评价海岸工程建设对近岸海域生态系统的影响,进一步深入研究海岸工程建设对近岸海洋生态影响预测模型将显得尤为重要。     

沿海港口煤炭专业化运输系统适应性探讨

结合全国煤炭生产消费及调运情况,分析北方煤炭下水港布局、后方铁路通道规划建设及煤炭下水趋势对专业化煤炭下水港未来发展的影响,研究南方煤炭接卸港码头布局、外贸进口煤炭和煤炭中转基地建设及接卸港发展趋势对接卸港布局及建设的影响,对全国沿海港口煤炭专业化运输系统分区域、分结构的适应性进行探讨,并提出问题及建议。     

Adapting without Retreating: Responses to Shoreline Change on an Inlet-Associated Coastal Beach

Coastal barrier systems around the world are experiencing higher rates of flooding and shoreline erosion. Property owners on barriers have made significant financial investments in physical protections that shield their nearby properties from these hazards, constituting a type of adaptation to shoreline change. Factors that contribute to adaptation on Plum Island, a developed beach and dune system on the North Shore of Massachusetts, are investigated here. Plum Island experiences patterns of shoreline change that may be representative of many inlet-associated beaches, encompassing an equivocal and dynamically shifting mix of erosion and accretion. In the face of episodic floods and fleeting erosive events, and driven by a combination of strong northeast storms and cycles of erosion and accretion, the value of the average Plum Island residence increases by 34% for properties on the oceanfront where protection comprises a publicly constructed soft structure. Even in the face of state policies that ostensibly discourage physical protection as a means of adaptation, coastal communities face significant political and financial pressures to maintain existing protective structures or to allow contiguous groups of property owners to build new ones through collective action. These factors mitigate against adapting to shoreline change by retreating from the coast, thereby potentially increasing the adverse effects of coastal hazards.     

Shaping the Coast with Permits: Making the State Regulatory Permitting Process Transparent with Text Mining

This paper examines the California Coastal Commission's permitting process. Using several text mining techniques, including web scraping, information extraction, and supervised classification, I demonstrate how to retrieve empirical data from unstructured texts, namely public meeting agendas and staff reports. Contrary to the concern that the Commission routinely delays or rejects permitting requests, the data reveal that outright rejection of permit applications is rare. On average, eight of ten applications were approved. Single-family homes and commercial development projects were approved about 80% of the time; the rates were about 70% for seawalls and retaining walls, and 60% for land-use changes. Most applications were processed swiftly, with a median application length of 3 months. The agency's influence comes primarily from negotiating each application. Qualitative study of 50 cases pertaining to single-family home construction reveals that the agency adopts a “managed development” approach, that is, allowing development but scrupulously managing various aspects of development. These case studies illustrate how the agency interprets the broad, abstract state laws and translates the mandates into enforceable actions as permitting conditions. In areas where the state mandates conflict, particularly over development in receding shorelines, the agency has the largest leverage in creating and implementing its preferred policies. The text mining techniques demonstrated in this paper can be applied to study any governmental agency. These techniques help to extract information from a massive volume of papers and organize them into a database for analyses. The empirical data extracted from texts can significantly increase bureaucratic transparency.     

长江口软基围堤施工的加载速率效应

针对长江口某围堤施工软土堆载过程中的稳定性问题,进行不同加载模式下的应力路径试验,分析长江口软黏土的应力-应变关系、结构损伤特性、强度及应变率发展模式,为该围堤工程的施工速率选取及施工过程中的稳定性控制提供技术依据。结果表明:在不考虑固结的前提下,土体的不排水抗剪强度几乎不受加载模式影响;最终强度与达到破坏时的应变大小无关,但与分级加载时间和分级静置时间存在相互作用关系;土体失稳时的应变率与加载速率和静置时间均有一定关系,且加载速率的影响更大;当加荷超过不排水抗剪强度的80%时,或分级最大应变率逐渐偏离加载初期的线性变化,土样濒临破坏。     

护坡结构在Mirsarai海岸防护工程中的应用

传统的混凝土或生态型护坡结构均不能兼顾海岸防护对结构防浪消能、耐久性、生态性的需求。针对孟加拉Mirsarai海岸防护工程特点,并经方案比选,采用混凝土块体与生态组合型护坡结构,对其技术质量重难点、典型施工问题、基槽镇脚棱体和坡面块体的防浪稳定性、生态护坡与结构排水进行分析。结果表明,基槽与坡面块体稳定质量满足防浪要求,能够有效抵御汛期海浪冲击;植被生态型护坡利用根系加固土层,控制土粒及下部材料冲刷流失,并兼具生态与景观作用。     

把南通港建成长三角最具活力的亿吨强港

介绍了南通港口2006年货物吞吐量突破亿吨所取得的成绩,并从“沿江开发、江海联动”的发展战略着眼,提出了从“亿吨大港”,向“亿吨强港”进取,切实需着重抓好的几个方面的工作。