深基坑周边环境沉降变形及监测研究
发布时间：2018-07-16 13:43
【摘要】：近年来，随着城市建设步伐日益推进，基坑工程的数量在不断增长，基坑开挖的深度越来越深，而周边环境相邻建筑物、地下管道相距很近，导致在开挖和支护过程中遇到的问题十分复杂，深基坑周边环境沉降变形是其中突出的技术难点之一，本文结合实际工程对基坑设计和监测环节中出现的问题展开研究。 通过构建有限元模型，对基坑的开挖卸荷及降水过程展开数值模拟，得到了基坑周边环境变形情况的计算结果，为科学判断邻近基坑工程受沉降影响程度提供了依据，为基坑变形监测工作开展提供了前提条件，同时也验证了复杂工况下深基坑支护方案的正确性。 在大量变形监测数据的基础上，以各监测点的最大沉降速率值为研究对象，采用统计分析法对基坑周边环境沉降变形数据进行信息挖掘，根据绘制的百分比饼图和柱形图，发现监测数据与预先设定的报警值有较大差别，高频段沉降速率出现的概率很低。因此，对沉降速率报警值进行了修正，建立了二级预警机制，并应用于工程实际。 利用指数曲线模型、双曲线模型和灰色模型，基于误差绝对值加权和最小的准则，借助MATLAB软件计算加权平均数，创建出预测精度更高的加权组合模型，，对深基坑周边建筑物的沉降变形进行预测分析。借助周边建筑物沉降变形速率预测值与报警值的比对结果，确定了沉降观测周期的长短。
[Abstract]:In recent years, with the increasing pace of urban construction, the number of foundation pit engineering is increasing, the excavation depth of foundation pit is getting deeper and deeper, and the adjacent buildings in the surrounding environment, underground pipelines are very close to each other. The problems encountered in excavation and support are very complex, and the settlement and deformation of the surrounding environment of deep foundation pit is one of the prominent technical difficulties. This paper studies the problems in the design and monitoring of foundation pit combined with practical engineering. By constructing the finite element model, the numerical simulation of excavation unloading and dewatering process is carried out, and the calculation results of the surrounding environment deformation of the foundation pit are obtained, which provides the basis for scientifically judging the degree of settlement influence on the adjacent foundation pit engineering. It provides a prerequisite for foundation pit deformation monitoring and verifies the correctness of deep foundation pit support scheme under complex working conditions. On the basis of a large number of deformation monitoring data, taking the maximum settlement rate value of each monitoring point as the research object, using the statistical analysis method to mine the settlement and deformation data of the surrounding environment of foundation pit, according to the percentage pie chart and the column chart drawn, It is found that there is a great difference between the monitoring data and the pre-set alarm value, and the probability of settlement rate in high frequency band is very low. Therefore, the warning value of settlement rate is revised, and the secondary warning mechanism is established, which is applied to engineering practice. Using exponential curve model, hyperbolic model and grey model, based on the criterion of weighted and minimum absolute value of error, a weighted combination model with higher prediction accuracy is established by using MATLAB software to calculate the weighted average. The settlement deformation of buildings around deep foundation pit is predicted and analyzed. The length of settlement observation period is determined by comparing the prediction value of settlement deformation rate with the warning value.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU433
本文编号：2126574
[Abstract]:In recent years, with the increasing pace of urban construction, the number of foundation pit engineering is increasing, the excavation depth of foundation pit is getting deeper and deeper, and the adjacent buildings in the surrounding environment, underground pipelines are very close to each other. The problems encountered in excavation and support are very complex, and the settlement and deformation of the surrounding environment of deep foundation pit is one of the prominent technical difficulties. This paper studies the problems in the design and monitoring of foundation pit combined with practical engineering. By constructing the finite element model, the numerical simulation of excavation unloading and dewatering process is carried out, and the calculation results of the surrounding environment deformation of the foundation pit are obtained, which provides the basis for scientifically judging the degree of settlement influence on the adjacent foundation pit engineering. It provides a prerequisite for foundation pit deformation monitoring and verifies the correctness of deep foundation pit support scheme under complex working conditions. On the basis of a large number of deformation monitoring data, taking the maximum settlement rate value of each monitoring point as the research object, using the statistical analysis method to mine the settlement and deformation data of the surrounding environment of foundation pit, according to the percentage pie chart and the column chart drawn, It is found that there is a great difference between the monitoring data and the pre-set alarm value, and the probability of settlement rate in high frequency band is very low. Therefore, the warning value of settlement rate is revised, and the secondary warning mechanism is established, which is applied to engineering practice. Using exponential curve model, hyperbolic model and grey model, based on the criterion of weighted and minimum absolute value of error, a weighted combination model with higher prediction accuracy is established by using MATLAB software to calculate the weighted average. The settlement deformation of buildings around deep foundation pit is predicted and analyzed. The length of settlement observation period is determined by comparing the prediction value of settlement deformation rate with the warning value.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU433
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