深基坑喷锚支护体系的优化设计及稳定性分析

发布时间：2018-03-24 21:28

本文选题：喷锚支护　切入点：数值模拟　出处：《中国石油大学(华东)》2014年硕士论文

【摘要】：喷锚网支护是近年来应用于深基坑边坡支护中的一种新技术。该技术是在土内打入一定数量的锚杆,使其与土体共同作用,增加强度和土体的整体性能。该方法稳定可靠,具有造价低、工期短、使用范围广等特点。因此,开展对深基坑喷锚支护技术设计和稳定性的研究是十分有必要的。本文主要是基于校内工科实验楼E座基坑支护工程,利用FLAC3D有限差分软件分析了工程中喷锚支护各结构参数对基坑稳定性的影响另外,本文还分别研究了含水量变化及罐车和泵车工作时产生的振动载荷对基坑变形的影响。主要内容如下:1)根据实际工况的相关参数,运用FLAC 3D有限差分软件分析了基坑分层开挖过程中的土体变形,结果表明水平位移随开挖次数逐渐增加,但增加率却在不断减小。且在开挖过程中,由于喷锚支护结构的锚固作用,基坑土体的位移变形得到了有效控制。2)利用FLAC 3D有限差分软件分析了锚杆长度、竖向间距和倾角对基坑变形的影响,分析结果表明:当锚杆的长度增加,特别是锚固段长度增加时,基坑壁的水平位移和地表沉降呈现一个减小的趋势。锚杆竖向间距的减小,锚杆倾斜角度的增大,都能限制基坑土体的位移,提高锚杆的加固能力,使土体的整体性得到提高。3)通过模拟分析施工过程中含水量的变化,得出了含水量变化与基坑变形之间的关系曲线,结果表明,同一深度位置处,土体的位移变形随着含水量的增加而变大;同一含水量处,随着开挖深度的增加,土体的位移变形也越大。4)通过对模型施加不同计算周期的振动荷载,及对不同计算周期内的基坑位移变化情况的分析,基坑位移随计算周期的增加而增加,并且在基坑靠近边缘荷载处的变形最大,中间基本无变化;在边缘处,基坑位移在前10个计算周期内变化比较明显,后10个计算周期位移也有增加,但增加速率开始减小,使得基坑变形在后期趋于平稳。
[Abstract]:Shotcrete-anchor mesh support is a new technique used in slope support of deep foundation pit in recent years. This technique is to push a certain number of anchor rods into the soil, make it interact with soil, increase the strength and the overall performance of soil, and this method is stable and reliable. Therefore, it is necessary to study the technical design and stability of shotcrete anchor support for deep foundation pit. The influence of structural parameters of shotcrete anchor support on the stability of foundation pit is analyzed by FLAC3D finite difference software. The influence of the variation of water content and the vibration load of tank car and pump car on the deformation of foundation pit is also studied in this paper. The main contents are as follows: 1) according to the relevant parameters of actual working condition, FLAC 3D finite difference software is used to analyze the deformation of soil in the course of delamination excavation of foundation pit. The results show that the horizontal displacement increases gradually with the times of excavation, but the increasing rate is decreasing. Because of the anchoring effect of shotcrete anchor support structure, the displacement and deformation of foundation pit soil are effectively controlled. 2) the influence of bolt length, vertical spacing and inclination angle on foundation pit deformation is analyzed by using FLAC 3D finite difference software. The results show that when the length of anchor rod increases, especially the length of anchoring section increases, the horizontal displacement and ground subsidence of foundation pit wall show a decreasing trend. Can limit the displacement of foundation pit soil, improve the reinforcement ability of anchor rod, and improve the integrity of soil. 3) by simulating and analyzing the change of water content during construction, the relationship curve between the change of water content and deformation of foundation pit is obtained. The results show that the displacement deformation of soil increases with the increase of water content at the same depth, and increases with the increase of excavation depth at the same water content. The larger the displacement deformation of soil is, the more the displacement of foundation pit increases with the increase of calculation period by applying the vibration load of different calculation periods to the model and analyzing the variation of foundation pit displacement in different calculation periods. And the deformation near the edge of the foundation pit is the largest and the middle is basically unchanged. At the edge, the displacement of the foundation pit changes obviously in the first 10 calculation cycles, and the displacement of the last 10 periods also increases, but the increasing rate begins to decrease. The deformation of foundation pit tends to be stable in the later stage.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU473.2

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