Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example t...Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.展开更多
Municipal civil engineering is the key content of municipal construction,and the construction scale is usually large.The quality of the project plays an important role in the development of urban economy.Due to the ra...Municipal civil engineering is the key content of municipal construction,and the construction scale is usually large.The quality of the project plays an important role in the development of urban economy.Due to the rapid increase of high-rise buildings,skyscrapers and underground buildings,the construction technology of deep foundation pit support has gradually become an indispensable construction technology.Therefore,the selection of foundation pit support construction technology is crucial in ensuring that whether the foundation is firm and stable,and whether the subsequent construction activities can be carried out smoothly.In view of this,the article discusses the application of deep foundation pit support construction technology in municipal civil engineering,aiming to provide reference for subsequent projects.展开更多
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 ...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.展开更多
为探究地铁深基坑施工安全风险因素动态作用规律,科学预防施工安全事故,针对目前缺乏因素系统识别、因果关系量化和动态推理分析等共性问题,提出一种基于决策试验和评估实验室(Decision Making Trial and Evaluation Laboratory DEMATEL...为探究地铁深基坑施工安全风险因素动态作用规律,科学预防施工安全事故,针对目前缺乏因素系统识别、因果关系量化和动态推理分析等共性问题,提出一种基于决策试验和评估实验室(Decision Making Trial and Evaluation Laboratory DEMATEL)与模糊认知图(Fuzzy Cognitive Map,FCM)的地铁深基坑施工安全风险分析方法。首先,通过理论分析与文献梳理,采用扎根理论识别风险因素;其次,结合专家调研与量化分析,利用DEMATEL方法分析风险因素的因果关系;再次,将DEMATAL决策矩阵转化为FCM模型的交互作用矩阵,展开风险因素的预测与诊断推理分析;最后,选取案例进行实证,验证模型方法的可用性与有效性。结果显示:因素X_(1)(人员安全风险意识)对其他因素的影响程度最高;因素X_(1)(人员安全风险意识)、X_(8)(安全施工组织设计方案)和X_(7)(施工安全风险管理措施)是排名前3的关键风险因素;完善安全施工组织设计方案是最有效的管控对策。展开更多
文摘Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.
文摘Municipal civil engineering is the key content of municipal construction,and the construction scale is usually large.The quality of the project plays an important role in the development of urban economy.Due to the rapid increase of high-rise buildings,skyscrapers and underground buildings,the construction technology of deep foundation pit support has gradually become an indispensable construction technology.Therefore,the selection of foundation pit support construction technology is crucial in ensuring that whether the foundation is firm and stable,and whether the subsequent construction activities can be carried out smoothly.In view of this,the article discusses the application of deep foundation pit support construction technology in municipal civil engineering,aiming to provide reference for subsequent projects.
基金supported by the Researches on the Control of Confined Water Drawdown and Subsidence in Foundation Pit Projects (Project No. JS-KY16R009-1)this project is funded by Shanghai Metro Line 18 Development Co., Ltd.
文摘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.
文摘为探究地铁深基坑施工安全风险因素动态作用规律,科学预防施工安全事故,针对目前缺乏因素系统识别、因果关系量化和动态推理分析等共性问题,提出一种基于决策试验和评估实验室(Decision Making Trial and Evaluation Laboratory DEMATEL)与模糊认知图(Fuzzy Cognitive Map,FCM)的地铁深基坑施工安全风险分析方法。首先,通过理论分析与文献梳理,采用扎根理论识别风险因素;其次,结合专家调研与量化分析,利用DEMATEL方法分析风险因素的因果关系;再次,将DEMATAL决策矩阵转化为FCM模型的交互作用矩阵,展开风险因素的预测与诊断推理分析;最后,选取案例进行实证,验证模型方法的可用性与有效性。结果显示:因素X_(1)(人员安全风险意识)对其他因素的影响程度最高;因素X_(1)(人员安全风险意识)、X_(8)(安全施工组织设计方案)和X_(7)(施工安全风险管理措施)是排名前3的关键风险因素;完善安全施工组织设计方案是最有效的管控对策。
