| In recent decades,the economic level of Chinese cities has developed rapidly.The impact of this is the continuous increase of urban population and the continuous expansion of urban size.With the expansion of the city,many cities have built a number of high-rise and super high-rise buildings.At the same time,in order to alleviate the traffic congestion caused by the increase in population,many cities have also built subway projects.Therefore,in major cities,the number of deep foundation pit projects has become more and more.With the continuous development of deep foundation pit engineering,the depth of foundation pit excavation is deepened,and the area is also increased.The safety of deep foundation pit excavation has gradually attracted people's attention.Supporting engineering is one of the most important links in deep foundation pit engineering.The support methods of deep foundation pits increase with the continuous development of deep foundation pit engineering.Nowadays,the environment around the deep foundation pit project is becoming more and more complex,and the surrounding uncertainties have also increased a lot.Therefore,the design and construction difficulties of the deep foundation pit project increase with the surrounding complex environment and various uncertain factors.There are many factors that need to be considered in the design of deep foundation pit engineering,not only the safety of foundation pit engineering,but also whether it can save materials and the rationality of construction.In the current various deep foundation pit support methods,pile-anchor support is widely used in many deep foundation pit support projects due to its good stability,low cost and low requirements for the foundation pit support environment.This article takes the deep foundation pit project of Liuzhou,Guangxi Zhuang Autonomous Region as an example,uses the finite element software Midas GTS for numerical simulation,and analyzes the horizontal and vertical displacements of the foundation pit and the soil body during excavation Bulge.Comparing the data obtained through numerical simulation analysis with the on-site monitoring data,it is found that the data obtained through simulation is correct and effective.In the finite element software simulation analysis,it can be predicted in advance that the location of the foundation pit displacement and the amount of soil uplift is large when the foundation pit is excavated.These analyses can provide a reference for monitoring units to deploy monitoring points.By laying monitoring points in advance and using the data provided by the monitoring points,it is possible to guide the excavation of the foundation pit and prevent collapseaccidents during the excavation of the foundation pit.The data obtained can also provide data support for subsequent similar engineering cases.The main contents of this article are as follows:(1)This paper introduces the background of topic selection of pile-anchor support for deep foundation pits,the history and development of deep foundation pit engineering research at home and abroad,as well as some foundation pit collapse accidents in the development of deep foundation pit engineering in my country,and summarizes the experience and lessons.At the same time,it explains the significance,content and technical route of the research.(2)The basic earth pressure theory and classic earth pressure theory and their calculation formulas are described.The calculation theory of the pile-anchor supporting structure is introduced to make the numerical analysis of the pile-anchor supporting in this paper have a theoretical basis.(3)Introduce actual engineering cases,and select the appropriate support scheme through the geological conditions of the project location and the surrounding environment.Introduced several commonly used foundation pit support types and application scopes,and gave a mechanical analysis of pile-anchor support,explaining the reasons for choosing pile-anchor support scheme in this project.(4)A brief introduction to the application of the finite element method,as well as the characteristics,analysis functions and basic operation flow of Midas GTS software.The excavation steps were simulated and analyzed using Midas GTS software,and the horizontal displacement and vertical displacement deformation and soil uplift during foundation excavation were also predicted.Through the software post-processing mode,the calculation results and calculation cloud map are derived,and the horizontal displacement and vertical displacement of the foundation pit and the position where the soil uplift is the largest in the cloud map are analyzed.(5)The purpose and significance of foundation pit monitoring and the orientation of foundation pit monitoring points are introduced.Comparing the data obtained by numerical simulation with the site pit monitoring data verifies the rationality of the supporting scheme,and at the same time,the analyzed results can provide reference for similar projects in the later period.Figure:[31] table:[7] reference:[60]... |
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