小应变本构模型在留有反压土的基坑开挖变形中的应用
发布时间：2019-01-19 14:49
【摘要】：基坑开挖一般是建筑物建设的第一阶段,对建筑物的稳定,邻近建筑物、基础设施的稳定也有着重要的影响,分析好基坑开挖的变形意义重大。目前应用最广、效果较好的是数值模拟计算方法。但数值分析方法中存在选取合适的本构模型这一问题,通过本文数值模拟发现,不同的本构模型得出的计算结果相差很大。本文利用数值计算软件PLAXIS 3D来模拟实际工程基坑开挖,重点说明了各种本构模型的理论基础和适用范围,得出在反映基坑开挖变形方面小应变本构模型有着一定的优势的结论。主要包含以下三个方面的内容:(1)全方位介绍了基坑开挖的变形模式及变形预测方法;比较了不同土体本构模型的理论基础、适用范围、优缺点,重点介绍了小应变本构模型。(2)介绍了数值分析软件PLAXIS 3D,利用PLAXIS 3D软件自带的小应变本构模型分析了基坑开挖预留反压土对基坑变形的影响。主要利用控制变量法,控制预留反压土的剖面形状、自身重量,对比不同情形下基坑开挖的变形。并将反压土重量分别增大10%和20%,增大的重量用于提高预留反压土台的稳定,具体措施是分别使其预留宽度和高度最大化、角度最小化,分析此时基坑变形,结果表明减小反压土的坡度对基坑稳定最好。(3)给出了得到小应变本构模型(HSS)参数的试验方法及参数意义,结合某工程实例,利用其实测数据与小应变本构模型和硬化土本构模型计算结果比对,也验证了小应变本构模型在模拟实际工程基坑开挖方面的优越性。
[Abstract]:Excavation of foundation pit is generally the first stage of building construction, which has an important influence on the stability of buildings, adjacent buildings and infrastructure facilities, and it is of great significance to analyze the deformation of excavation. At present, numerical simulation method is the most widely used and effective method. However, there is a problem of choosing suitable constitutive model in the numerical analysis method. Through the numerical simulation in this paper, it is found that the calculation results of different constitutive models are very different. In this paper, the numerical calculation software PLAXIS 3D is used to simulate the excavation of practical engineering foundation pit. The theoretical basis and applicable range of various constitutive models are explained, and the conclusion is drawn that the small strain constitutive model has some advantages in reflecting the deformation of foundation pit excavation. It mainly includes the following three aspects: (1) the deformation mode and deformation prediction method of excavation are introduced in all directions; The theoretical basis, application scope, advantages and disadvantages of different soil constitutive models are compared, and the small strain constitutive models are emphatically introduced. (2) the numerical analysis software PLAXIS 3D is introduced. In this paper, the small strain constitutive model of PLAXIS 3D software is used to analyze the influence of pre-pressure soil on the deformation of foundation pit. The control variable method is mainly used to control the profile shape and weight of the reserved backpressure soil and to compare the deformation of foundation pit excavation under different conditions. The weight of the backpressure soil is increased by 10% and 20% respectively, and the increased weight is used to improve the stability of the reserved backpressure soil platform. The concrete measures are to maximize the reserved width and height, minimize the angle, and analyze the deformation of foundation pit. The results show that the stability of foundation pit is best to reduce the slope of backpressure soil. (3) the test method and parameter significance of (HSS) parameters of small strain constitutive model are given. The comparison of the measured data with the calculation results of the small strain constitutive model and the hardening soil constitutive model also verifies the superiority of the small strain constitutive model in simulating the excavation of practical engineering foundation pit.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753
本文编号：2411471
[Abstract]:Excavation of foundation pit is generally the first stage of building construction, which has an important influence on the stability of buildings, adjacent buildings and infrastructure facilities, and it is of great significance to analyze the deformation of excavation. At present, numerical simulation method is the most widely used and effective method. However, there is a problem of choosing suitable constitutive model in the numerical analysis method. Through the numerical simulation in this paper, it is found that the calculation results of different constitutive models are very different. In this paper, the numerical calculation software PLAXIS 3D is used to simulate the excavation of practical engineering foundation pit. The theoretical basis and applicable range of various constitutive models are explained, and the conclusion is drawn that the small strain constitutive model has some advantages in reflecting the deformation of foundation pit excavation. It mainly includes the following three aspects: (1) the deformation mode and deformation prediction method of excavation are introduced in all directions; The theoretical basis, application scope, advantages and disadvantages of different soil constitutive models are compared, and the small strain constitutive models are emphatically introduced. (2) the numerical analysis software PLAXIS 3D is introduced. In this paper, the small strain constitutive model of PLAXIS 3D software is used to analyze the influence of pre-pressure soil on the deformation of foundation pit. The control variable method is mainly used to control the profile shape and weight of the reserved backpressure soil and to compare the deformation of foundation pit excavation under different conditions. The weight of the backpressure soil is increased by 10% and 20% respectively, and the increased weight is used to improve the stability of the reserved backpressure soil platform. The concrete measures are to maximize the reserved width and height, minimize the angle, and analyze the deformation of foundation pit. The results show that the stability of foundation pit is best to reduce the slope of backpressure soil. (3) the test method and parameter significance of (HSS) parameters of small strain constitutive model are given. The comparison of the measured data with the calculation results of the small strain constitutive model and the hardening soil constitutive model also verifies the superiority of the small strain constitutive model in simulating the excavation of practical engineering foundation pit.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753
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