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针对地下空间开发中深基坑减压降水地面沉降发育特征、沉降机制及防治对策等研究进展,以上海市为例,总结了近年来滨海地区深基坑减压降水地面沉降研究取得的主要成果。建立了深基坑减压降水地面沉降防治综合分区方法,探索了深基坑减压降水地面沉降防治原型试验设计方法,掌握了上海市浅部承压含水层深基坑减压降水地面沉降规律,提出了深基坑减压降水地面沉降-地下水位双控模式及控制指标,提出了深基坑减压降水地面沉降防治措施,构建了深基坑减压降水地面沉降管控体系。这些研究成果在特大型城市安全管理、重大市政工程建设及运营服务中得到应用,对同类地区地面沉降研究和防治工作具有借鉴意义。 相似文献
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上海地面沉降近年呈现出不均匀性特征,深基坑减压降水等工程活动是其主要原因之一.根据某地铁车站深基坑工程减压降水和地质环境监测结果,分析了深基坑工程的地面沉降效应.研究表明,减压降水是导致基坑周边地面沉降的主要因素,浅层地下水回灌可作为地面沉降控制的有效措施,而基坑围护与工程降水一体化设计是未来工程性地面沉降防治的重要方向.该研究成果可为工程性地面沉降防治提供科学依据和实践指导. 相似文献
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地面沉降是我国东部沿海平原地区城市化进程中资源与环境由对立走向统一的焦点之一。上海市区地面沉降系统的监测、研究与防治工作起步较早,所取得的成果与经验需要认真的总结与深刻反思。本文仅对其中的部分现象与问题提出了个人意见。 上海市地下水与地面沉降的动态监测已四十年,对地面沉降规律、机理与防治措施的研究取得显著的成果。现在,上海市地 相似文献
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为了精确模拟预测松散沉积层中深基坑降水引起的地下水渗流场和地面沉降的变化特征,考虑土体孔隙度、渗透系数、储水率随地下水位下降发生的动态变化,建立了深基坑降水三维变参数非稳定渗流与太沙基一维固结理论的地面沉降耦合模型,并采用有限元数值分析方法对模型进行求解。以南京地铁三号线浦珠路站深基坑降水为例进行模拟计算。结果表明：采用15口坑内抽水井,抽水井过滤器埋深为22.0～37.0 m,基坑围护连续墙底部埋深至41.5 m为最优降水方案;不仅使基坑内地下水位满足开挖要求,又使基坑外地面沉降在控制范围内。经验证,所建立的模型合理,计算结果可靠,研究理论用于模拟预测此类地区深基坑降水引起的地下水流场变化具有较高的可信度。 相似文献
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地面沉降是上海地区最主要的地质灾害类型,对上海市经济建设与可持续发展造成了较为明显的影响。解放后．上海市不断探寻科学有效的地面沉降防治措施。1965年,通过大规模压缩地下水开采、开展地下水人工回灌、调整地下水开采层次等措施,有效的控制了地面沉降的发展。但随着改革开放和经济建设的发展,地下水的开发利用规模不断加大,上世纪90年代末以来,地面沉降又呈现出微量增长的态势,为此,“十五”期间,上海市进一步采取措施,开展地下水专门回灌工作,并针对工程建设对地面沉降影响开展研究,进一步拓展了地面沉降研究领域并加强了地面沉降防治管理。要使地面沉降防治工作得到全社会的重视,没有相关的法律法规是难以实现的,“上海市地面沉降防治管理办法”的正式出台,标志着地面沉降防治工作将有法可依,将进一步规范地面沉降防治与管理工作。本文将结合“上海市地面沉降防治管理办法”,回顾上海市地面沉降防治管理措施开展所取得的效果,并对进一步加强地面沉降管理与法制建设提出建议。 相似文献
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上海地面沉降风险评价及防治管理区建设研究 总被引：3，自引：3，他引：0
在阐述地面沉降风险基本内涵及特征基础上,以上海市为例,详细介绍了地面沉降风险评价的工作流程、评价指标及评价方法。以地面沉降风险评价结果为基础,结合上海目前地面沉降防治工作体系,将地面沉降风险管理与地面沉降防治管理主体相结合,提出了＂十二五＂期间上海地面沉降风险管理区建设方案。 相似文献
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结合上海城区某深基坑工程,针对项目特点与场区地质条件,分析了工程建设可能引发的基坑水土突涌、基坑边坡稳定、砂土渗流液化、基坑开挖和降水过程中地基变形和地面沉降等环境地质问题,进行危险性评价,并提出了防治对策措施。 相似文献
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In terms of controlling groundwater in deep foundation pit projects, the usual methods include increasing the curtain depth, reducing the amount of pumped groundwater, and implementing integrated control, in order to reduce the drawdown and land subsidence outside pits. In dewatering design for confined water, factors including drawdown requirements, the thickness of aquifers, the depth of dewatering wells and the depth of cutoff curtains have to be considered comprehensively and numerical simulations are generally conducted for calculation and analysis. Longyang Road Station on Shanghai Metro Line 18 is taken as the case study subject in this paper, a groundwater seepage model is developed according to the on-site engineering geological conditions and hydrogeological conditions, the excavation depth of the foundation pit as well as the design depth of the enclosure, hydrogeological parameters are determined via the pumping test, and the foundation pit dewatering is simulated by means of the three-dimensional finite difference method, which produces numerical results that consistent with real monitoring data as to the groundwater table. Besides, the drawdown and the land subsidence both inside and outside the pit caused by foundation pit dewatering are calculated and analyzed for various curtain depths. This study reveals that the drawdown and the land subsidence change faster near the curtain with the increase in the curtain depth, and the gradient of drawdown and land subsidence changes dwindles beyond certain depths. In this project, the curtain depth of 47/49 m is adopted, and a drawdown-land subsidence verification test is completed given hanging curtains before the excavation. The result turns out that the real measurements basically match the calculation results from the numerical simulation, and by increasing the depth of curtains, the land subsidence resulting from dewatering is effectively controlled. 相似文献
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In terms of controlling groundwater in deep foundation pit projects, the usual methods include increasing the curtain depth, reducing the amount of pumped groundwater, and implementing integrated control, in order to reduce the drawdown and land subsidence outside pits. In dewatering design for confined water, factors including drawdown requirements, the thickness of aquifers, the depth of dewatering wells and the depth of cutoff curtains have to be considered comprehensively and numerical simulations are generally conducted for calculation and analysis. Longyang Road Station on Shanghai Metro Line 18 is taken as the case study subject in this paper, a groundwater seepage model is developed according to the on-site engineering geological conditions and hydrogeological conditions, the excavation depth of the foundation pit as well as the design depth of the enclosure, hydrogeological parameters are determined via the pumping test, and the foundation pit dewatering is simulated by means of the three-dimensional finite difference method, which produces numerical results that consistent with real monitoring data as to the groundwater table. Besides, the drawdown and the land subsidence both inside and outside the pit caused by foundation pit dewatering are calculated and analyzed for various curtain depths. This study reveals that the drawdown and the land subsidence change faster near the curtain with the increase in the curtain depth, and the gradient of drawdown and land subsidence changes dwindles beyond certain depths. In this project, the curtain depth of 47/49 m is adopted, and a drawdown-land subsidence verification test is completed given hanging curtains before the excavation. The result turns out that the real measurements basically match the calculation results from the numerical simulation, and by increasing the depth of curtains, the land subsidence resulting from dewatering is effectively controlled. 相似文献
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基坑开挖是建筑物基础施工的重要阶段,在软土地区常因地质条件的特殊性导致诸多环境地质问题,并可引发工程事故或安全隐患。结合某高层建筑基坑开挖与降水作业工程实例,分析了水土突涌、地面沉降等环境地质问题及其产生原因,提出了软土地区基础施工过程中地质灾害防治措施与对策建议。 相似文献
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长江三角洲地区深基坑降水复杂,且极易引起地面沉降地质灾害问题,传统的基于地下水动力学原理的解析解模型(Theis公式或Dupuit公式)已难以满足降水设计模拟计算的需要,尤其是无法预测降水引起的地面沉降问题,深基坑降水与地面沉降耦合模型将地下水渗流模型和土体应力-应变模型耦合起来,可根据基坑地下水位的控制要求,同时模拟计算出降水井的布局、各井的开采量和地面沉降量。据此确定出的基坑降水方案既能满足地下水位的控制要求,又能对降水引起的地面沉降进行最优化控制。 相似文献
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基坑降水引起地面沉降的实时预测 总被引：9，自引：1，他引：8
由于基坑降水引起周围土体应力的重新调整,造成基坑相邻建筑物地基不均匀沉降,情况严重则造成相邻建筑物破坏,因此对不均匀沉降量的预测具有现实意义。利用地下水动力学的非稳定流原理及土力学基本理论,介绍了基坑降水设计中引起周围地面沉降的实时预测方法,探讨了不同土层在降水过程中孔隙水压力消散对土层固结的影响,通过实例分析了公式中不同参数的取值合理性,编制了相关程序。该方法对分析、预测由于基坑降水所引起的周围地面沉降有一定参考价值。 相似文献
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Ye-Shuang Xu Huai-Na Wu Bruce Zhi-Feng Wang Tian-Liang Yang 《Environmental Earth Sciences》2017,76(9):351
Foundation dewatering has become a major cause of land subsidence in Shanghai. The burial depth of foundations in relation to geotechnical construction works is less than 75 m, and the corresponding groundwater includes phreatic, low-pressure artesian, and the first confined aquifers. Based on the geological and hydrogeological conditions beneath Shanghai, methods of dewatering may be divided into three modes and further five patterns according to the insertion depth of the dewatering-retaining system. The most common dewatering mode aims to reduce the water pressure in the confined aquifer by setting the dewatering wells inside the pit, whilst the retaining walls are buried in the confined aquifer and partially cut off the confined aquifer layer. To predict the settlement due to foundation dewatering, numerical models are generally adopted, which are similar to those used to predict land subsidence induced by regional groundwater withdrawal; however, since foundation dewatering is conducted along with the setting of retaining walls and foundation pit excavation, which differs from regional groundwater withdrawal, interactions between the retaining wall-dewatering well, the dewatering-excavation, and dewatering-recharge are important factors affecting the analytical model. Since the grading of the shallow soil layers is different, stratified settlement characteristics of the shallow soil strata and seepage erosion, which results in additional deformation, need to be given particular consideration. 相似文献
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浅层地下水人工回灌应用于上海市工程性地面沉降防治的试验研究 总被引：1，自引：0，他引：1
上海地面沉降主要由过量开采地下水资源和大规模工程建设等因素共同影响,工程性地面沉降引起的地面沉降漏斗严重影响了周边地区生命线工程的建设及运营安全。通过开展试验研究,将深部承压含水层中应用成熟的地下水人工回灌技术引入浅部含水层中,但由于浅部含水层砂层结构及水动力条件与深部含水层差异较大,回灌工艺及方法也存在差异。本次试验工作中,改进了地下水人工回灌工艺流程,并通过同步地面形变监测分析了浅层地下水人工回灌对控制地面沉降的作用效果。结合上海地区实际地层特征以及各种回灌工艺的实际效果,评价了浅层地下水人工回灌技术在防治工程型地面沉降中推广应用的可行性及适用性。 相似文献
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20世纪90年代上海中心城区的地面沉降在地下水开采量没有增加的情况下出现了新一轮的增长。与此同时,上海进行了大规模的城市化建设。通过对中心城区地面沉降量与工程建设进行相关性分析发现,近年来中心城区的地面沉降量与工程建设具有相关性。目前城市化建设引起地面沉降的现象已受到关注,但尚缺乏对城市化进程引起地面沉降机制的系统研究。针对上海市城市化进程引起地面沉降的因素进行分析探讨,城市化进程引起的沉降包括建筑物荷载及交通荷载等外荷载引起的沉降,基坑开挖、降水及隧道施工等工程施工引起的土体压缩,以及隧道渗漏,周边地区对地下水补给量的减小,地下构筑物挡水效应等引起的地下水位持续下降而诱发的沉降 相似文献
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X.-S. Zhang J.-X. Wang H. Wong C.-J. Leo Q. Liu Y.-Q. Tang X.-L. Yan W.-H. Sun Z.-Q. Huang X.-H. Hao 《Natural Hazards》2013,69(1):473-489
Land subsidence is presented in many factors in different areas with urbanization. Internal soil erosion, owing to pumping confined groundwater during the deep foundation pit construction, has contributed to land subsidence. Four governing equations are presented to describe the process of internal soil erosion based on the mathematical–physical model. The finite element computation results, based on practical deep foundation pit engineering consisted of 8 layers of soil of Shanghai area, demonstrate that internal soil erosion will cause the increment of land subsidence and deformation and is related to the hydraulic gradient and the characters of the soils. 相似文献