上海地面沉降及其对城市安全影响

地面沉降是上海最主要的地质灾害.半个多世纪以来,地面沉降已使上海区域地貌形态发生显著变化,目前中心城区高程普遍小于3.5m.监测资料表明,累计地面沉降总量对城市防汛产生重大影响,而地面沉降在空间上的发育不均匀性,对穿越不同地面沉降速率空间的线性城市基础设施的安全运营影响是严重的.     

地面沉降控制论初论：以上海地面沉降为例

本文首次运用控制论的原理和方法，初步建立了控制地面沉降灾害的新理论新方法－地面沉降控制论。认为控制地面沉降的实质是控制灾害性地面沉降的发生，由此将在规划时期内市政设施所容许的地面沉降量，作下水运动与地面沉降耦合模型，预测年度地面沉降量。通过与年度容许地面沉降量的比较，运行反馈模型调整地下水采灌量，再运行耦合模型，直至找到最佳的地下水采灌量方案。     

上海城市可持续发展与地面沉降防治管理

上海的地面沉降在国内外具有典型性。沉降洼地的形成与发展在城市防汛、城区地面积水、重大线型工程差异沉降影响等方面对上海城市的可持续发展带来不利影响。地面沉降也通过洪涝、潮汛等显性灾害的成灾风险与致灾频率的增加，而体现出缓变型灾害的本质。上海目前已对全市地下水资源的开发利用实施有序管理，建立了覆盖全市整个陆域与第四纪地层的地面沉降监测网络体系，并融入了自动化测控与GPS监测等高新技术手段。同时密切结合城市总体建设发展规划，开展针对性的专题研究，深化城市地质工作，并注重与长江三角洲地区的联动。以科学有效的管理，落实可持续发展战略，使地区经济发展与地质生态环境保护协调统一。     

上海地面沉降监控中心

1 前言 上海自二十世纪六十年代初开始系统的开展地面沉降研究工作,至今已积累了大量的监测数据资料,近年来地面沉降监测设施不断完善,至2000年底已建成了覆盖全市范围的具有高新技术全新的地面沉降监测网络。     

上海地面沉降研究综述

对上海50余年的地面沉降研究工作进行了回顾与初步总结。     

市科委重大科研项目“上海市地面沉降灾害经济损失评估”通过专家评审

2002年9月16日下午,上海市科学技术委员会邀请有关专家,在灵石路930号地质大厦六楼学术报告厅,组织召开了上海市科委重大科研项目“上海市地面沉降灾害经济损失评估”报告的成果评审会。 来自国内相关领域的共11位专家学者组成了评审委员会,他们分别是南京大学中国科学院薛禹群院     

我国城市地面沉降概况

本文通过对上海,天津、宁波、北京、苏锡常地区、西安、太原、阜阳等城市地面沉降的形成、发展及其治理过程的介绍和初步归纳,并根据我国经济、技术条件,提出:加强规划和指导、以“法”治沉,以及加强地下水资源合理开发利用等治理对策,从而达到减缓我国主要城市地面沉降速度和减轻其危害的社会,经济效果。     

我国地面沉降现状及防治对策研究

文章以长江三角洲、华北平原及汾渭地堑地区为重点提出开展全国地面沉降防治的建议。地面沉降主要是由于不合理开采地下水引发的一种区域性的缓变地质灾害，成灾慢，但损失大，不易治理。同时，在上述三大地区由于地面沉降还伴发了地裂缝灾害。粗略统计，1949年以来，我国地面沉降造成的损失累计高达4500—5000亿元，其中，年均总损失为90～100亿元，年均直接损失8～10亿元。文章建议：利用10～15a时间，综合研究第四系结构、含水层结构及地下水环境、基底地形与断块构造特征，建立三维可视化数字平台；查明全国地面沉降灾害分布状况和演化规律，开展地灾风险评估及地质环境安全功能区划；建成全国地面沉降现代化监测控制网络；开展地面沉降防治，严格控制地下水开采，实施以控制地面沉降为目标的含水层修复等减灾工程。文章总结了禁采或限采地下水、优化地下水开采层位、浅层地下水开发利用、地下水人工回灌与含水层修复等地面沉降防治经验。     

上海城区建筑密度与地面沉降关系分析

工程建设逐渐成为上海近年来新的地面沉降制约因素.本文选择4个典型的高层建筑及多层建筑密集区段,分析了建筑密度与地面沉降的关系,探讨了其时空变化特征.建筑规模及其增长速度直接导致工程性地面沉降同步增长,集中建设较分散建设、新区建设较旧城改造、高层建筑较多层建筑地面沉降效应明显.建筑密度越大,建筑容积率越高,地面沉降越显著.城市规划宜选择低密度、低容积率的建设模式,降低建筑高度、扩大建筑间距.提出了沉降控制条件下适宜的建筑容积率应在0.9～1.2之间,从而为城市规划提供了决策性技术指标.     

Land subsidence caused by ground water withdrawal in urban areas

At least eight urban areas in the world have encountered significant economic impact from land subsidence caused by pumping of ground water from unconsolidated sediment. The areas, most of which are coastal, include Bangkok, Houston, Mexico City, Osaka, San Jose, Shanghai, Tokyo, and Venice. Flooding related to decreased ground elevation is the principal adverse effect of the subsidence. Lesser effects include regional tilting, well-casing failures, rising buildings, and ground failure or rupture. Subsidence of most of these urban areas began before the phenomenon was discovered and understood. Thus, the subsidence problems were unanticipated. Methods to arrest subsidence typically have included control of ground water pumping and development of surface water to offset the reductions of ground water pumping. Ground water recharge has also been practiced. Areas threatened by flooding have been protected by extensive networks of dikes and sea walls, locks, and pumping stations to remove storm runoff.     

Land subsidence in China

Land subsidence in China occurs in different regions. It is primarily caused by excessive groundwater withdrawal. Other reasons for the subsidence include the oil, warm groundwater withdrawal and the neotectonic movement. The common characteristics of land subsidence in China are slow, accumulative, irreversible, and other unique properties. The range of subsidence still keeps extending and the accumulative subsidence increasing though some measures taken. Adjustment of the aquifer exploitation practice is a subsidiary way to control land subsidence, but it cannot solve this problem completely. In a specfic way of groundwater changing, the contribution of a certain soil layer to the total subsidence depends on its compressibility and thickness. Besides the elasticity, both cohesive soil layers (aquitards) and sand layers (aquifers) are observed to be plastic and creep when the groundwater level fluctuates in a specific way, which often leads to subsidence delay.     

Land subsidence of Jakarta (Indonesia) and its relation with urban development

Jakarta is the capital city of Indonesia with a population of about 9.6 million people, inhabiting an area of about 660 square-km. In the last three decades, urban development of Jakarta has grown very rapidly in the sectors of industry, trade, transportation, real estate, and many others. This exponentially increased urban development introduces several environmental problems. Land subsidence is one of them. The resulted land subsidence will also then affect the urban development plan and process. It has been reported for many years that several places in Jakarta are subsiding at different rates. The leveling surveys, GPS survey methods, and InSAR measurements have been used to study land subsidence in Jakarta, over the period of 1982–2010. In general, it was found that the land subsidence exhibits spatial and temporal variations, with the rates of about 1–15 cm/year. A few locations can have the subsidence rates up to about 20–28 cm/year. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil, and tectonic subsidence. It was found that the spatial and temporal variations of land subsidence depend on the corresponding variations of groundwater extraction, coupled with the characteristics of sedimentary layers and building loads above it. In general, there is strong relation between land subsidence and urban development activities in Jakarta.     

上海城市地下空间权利设置与土地管理研究

随着城市地下空间的大规模开发利用,地下建筑物确权登记的需求越来越紧迫。地下空间土地权利是确定地下建筑物产权的基础,通过研究地下空间土地权利设置以及土地管理方法,可以为建立地下建筑物产权制度奠定基础,对保障地下空间合理开发,提高地下空间利用效率,维护城市规划建设秩序具有重要意义。     

Land subsidence in Tianjin,China

Land subsidence has been affecting Tianjin for the past 50 years. It leads to comprehensive detrimental effects on society, the economy and natural environment. Overpumping of groundwater is the main cause. In 2008, the maximum cumulative subsidence reached 3.22 m and the total affected area nearly 8,000 km². The subsidence reached its most critical state in the early 1980s when it occurred at a rate as high as 110 mm/year. At the same time, groundwater extraction had also reached a maximum of 1,200 million m³. By importing the Luan River to Tianjin and restricting exploitation of groundwater, hydraulic heads gradually recovered after 1986 in all aquifers, and this has continued to the present in the second aquifer. The subsidence rate in urban areas dropped to 10–15 mm/year. The area of groundwater extraction expanded to the suburban area with economic growth in the 1990s, and it was shifted to the third and fourth aquifers. At present, with a subsidence rate of 30–40 mm/year, four new suburban subsidence centers have been formed. Several measures were adopted to mitigate and prevent land subsidence disasters. These included restricting groundwater exploitation, groundwater injection, prohibiting use in the specific zone, a pricing policy for water resources, advocating water-saving technology, and strict enforcement of groundwater laws. Although the subsidence area is still increasing slowly, the subsidence rate is being controlled.