重庆某深基坑变形预测研究
发布时间：2019-06-22 18:31
【摘要】：基坑开挖会产生基坑变形,变形的发展又会使基坑存在安全隐患,甚至会造成基坑事故,因此为达到对基坑事故事前控制的目的,基坑变形预测变得尤为重要。然而基坑工程复杂多样,目前基坑的变形预测缺乏比较成熟的理论指导,理论体系尚不健全。本论文以重庆某深基坑项目工程GH-HI-IA-AA'-A'B段为研究对象,该区段内采用了三种不同的高压旋喷水泥土桩墙复合支护结构进行支护,结合ABAQUS有限元方法对基坑天然工况以及暴雨工况下基坑变形进行了预测,并把ABAQUS预测结果与基坑实际监测数据的差值作为输入因子,利用BP神经网络方法对基坑的IA-AA'段10m深处基坑侧向变形进行预测,主要研究内容如下:(1)总结了目前基坑变形预测方法的利弊,指出多种方法相结合成为了目前主要的研究方向,本论文就是结合有限元分析法和系统分析法进行基坑的变形预测。(2)结合重庆某深基坑项目工程GH-HI-IA-AA'-A'B段,利用ABAQUS有限元方法,对天然工况下的基坑周边地表沉降、基坑底部隆起以及基坑侧向变形进行了预测,对比分析了 GH-HI段加筋高压旋喷水泥土墙+锚拉桩支护、IA-AA'段加筋高压旋喷水泥土墙支护、A'B段加筋高压旋喷水泥土墙+肋板式挡土墙支护三段不同支护方式的预测结果,归纳总结加筋高压旋喷水泥土墙不同复合支护方式的基坑变形规律。(3)暴雨工况下考虑基坑的渗流作用,利用ABAQUS对基坑周边地表沉降、基坑底部隆起以及基坑侧向变形进行了预测,对比基坑天然和暴雨工况基坑的变形特征,指出了暴雨工况下基坑变形有较明显的增大。(4)利用ABAQUS的模拟计算值与实测值的差值作为BP神经网络输入因子,对基坑IA-AA'段10m深处进行变形预测,对比ABAQUS有限元方法与BP神经网络法,表明BP神经网络法对基坑变形预测精度高,但可预见性较差,而ABAQUS有限元方法对基坑变形预测精度较低,可预见性好。
[Abstract]:The deformation of foundation pit will occur in foundation pit excavation, and the development of deformation will make the foundation pit have hidden danger of safety and even cause foundation pit accidents. Therefore, in order to control the foundation pit accident in advance, it is particularly important to predict the deformation of foundation pit. However, the foundation pit engineering is complex and diverse, and the deformation prediction of foundation pit is lack of mature theoretical guidance, and the theoretical system is not perfect. In this paper, the GH-HI-IA-AA'-A'B section of a deep foundation pit project in Chongqing is taken as the research object, in which three different composite supporting structures of high pressure rotary jet cement pile wall are used to support the foundation pit. Combined with the ABAQUS finite element method, the deformation of the foundation pit under natural and rainstorm conditions is predicted, and the difference between the ABAQUS prediction results and the actual monitoring data of the foundation pit is taken as the input factor. The BP neural network method is used to predict the lateral deformation of the foundation pit at the depth of 10 m in the IA-AA' section of the foundation pit. The main research contents are as follows: (1) the advantages and disadvantages of the current foundation pit deformation prediction methods are summarized, and it is pointed out that the combination of various methods has become the main research direction at present. In this paper, the deformation prediction of foundation pit is carried out by combining finite element analysis and system analysis. (2) combined with the GH-HI-IA-AA'-A'B section of a deep foundation pit project in Chongqing, the surface settlement around the foundation pit, the bottom uplift of the foundation pit and the lateral deformation of the foundation pit under natural working conditions are predicted by using the ABAQUS finite element method, and the reinforced high pressure rotary jet cement-soil wall anchor and pull pile support in the GH-HI section is compared and analyzed. The prediction results of reinforced high pressure rotary spray cement-soil wall support in IA-AA' section and reinforced high pressure rotary spray cement-soil wall ribbed plate retaining wall support in section A / B are summarized. (3) considering the seepage effect of foundation pit under rainstorm condition, ABAQUS is used to settle the surface around the foundation pit. The uplift at the bottom of the foundation pit and the lateral deformation of the foundation pit are predicted. Compared with the deformation characteristics of the foundation pit under natural and rainstorm conditions, it is pointed out that the deformation of the foundation pit under the rainstorm condition is obviously increased. (4) using the difference between the simulated calculated value and the measured value of ABAQUS as the input factor of the BP neural network, the deformation prediction of the IA-AA' section of the foundation pit is carried out, and the ABAQUS finite element method and the BP neural network method are compared. It is shown that BP neural network method has high accuracy but poor predictability for foundation pit deformation prediction, while ABAQUS finite element method has low accuracy and good predictability for foundation pit deformation prediction.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753
本文编号：2504851
[Abstract]:The deformation of foundation pit will occur in foundation pit excavation, and the development of deformation will make the foundation pit have hidden danger of safety and even cause foundation pit accidents. Therefore, in order to control the foundation pit accident in advance, it is particularly important to predict the deformation of foundation pit. However, the foundation pit engineering is complex and diverse, and the deformation prediction of foundation pit is lack of mature theoretical guidance, and the theoretical system is not perfect. In this paper, the GH-HI-IA-AA'-A'B section of a deep foundation pit project in Chongqing is taken as the research object, in which three different composite supporting structures of high pressure rotary jet cement pile wall are used to support the foundation pit. Combined with the ABAQUS finite element method, the deformation of the foundation pit under natural and rainstorm conditions is predicted, and the difference between the ABAQUS prediction results and the actual monitoring data of the foundation pit is taken as the input factor. The BP neural network method is used to predict the lateral deformation of the foundation pit at the depth of 10 m in the IA-AA' section of the foundation pit. The main research contents are as follows: (1) the advantages and disadvantages of the current foundation pit deformation prediction methods are summarized, and it is pointed out that the combination of various methods has become the main research direction at present. In this paper, the deformation prediction of foundation pit is carried out by combining finite element analysis and system analysis. (2) combined with the GH-HI-IA-AA'-A'B section of a deep foundation pit project in Chongqing, the surface settlement around the foundation pit, the bottom uplift of the foundation pit and the lateral deformation of the foundation pit under natural working conditions are predicted by using the ABAQUS finite element method, and the reinforced high pressure rotary jet cement-soil wall anchor and pull pile support in the GH-HI section is compared and analyzed. The prediction results of reinforced high pressure rotary spray cement-soil wall support in IA-AA' section and reinforced high pressure rotary spray cement-soil wall ribbed plate retaining wall support in section A / B are summarized. (3) considering the seepage effect of foundation pit under rainstorm condition, ABAQUS is used to settle the surface around the foundation pit. The uplift at the bottom of the foundation pit and the lateral deformation of the foundation pit are predicted. Compared with the deformation characteristics of the foundation pit under natural and rainstorm conditions, it is pointed out that the deformation of the foundation pit under the rainstorm condition is obviously increased. (4) using the difference between the simulated calculated value and the measured value of ABAQUS as the input factor of the BP neural network, the deformation prediction of the IA-AA' section of the foundation pit is carried out, and the ABAQUS finite element method and the BP neural network method are compared. It is shown that BP neural network method has high accuracy but poor predictability for foundation pit deformation prediction, while ABAQUS finite element method has low accuracy and good predictability for foundation pit deformation prediction.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753
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