Study on the Deformation of Supporting Structure for Foundation Pit in Strata with Rock-Soil Combination

2012 ◽  
Vol 446-449 ◽  
pp. 1797-1803
Author(s):  
Ai Jun Yao ◽  
Xin Dong Zhang ◽  
Xian Jun Zou

Taking the deformation of row pile supporting structure of foundation pit in strata with rock-soil combination as the research target and taking an open cut metro deep foundation pit as an example, by in-site monitoring and numerical simulation, analyze the horizontal displacement of retaining piles and the change law of steel support axial force in the strata with rock-soil combination, and summarize the change law of row pile supporting structure in the process of excavation under the conditions of this strata, so that to provide experience and guidance for similar engineering design and construction. The results show that: the structure of foundation pit has obvious effects on deformation and internal force of supporting structure, the result obtained from numerical simulation fits well with the tendency of monitoring data changing. In which, the deformation of row pile supporting structure in the middle and upper part of soil strata is larger, the deformation of middle and lower part of soil strata is comparatively smaller, the lateral deformation of row piles to basement has a tendency of gradual decreasing by taking the interface of rock-soil as a boundary.

2014 ◽  
Vol 937 ◽  
pp. 433-437
Author(s):  
Yi Zheng

Based on test data of the prestressed anchor cable composite soil nailing wall deformation and internal force of structure of Shenzhen Holiday Plaza foundation pit, the numerical simulation model of foundation pit is established by FLAC3D software. Through the reasonable selection of soil constitutive model and structural unit, the numerical simulation model is consistent with the project practice. The simulation results on horizontal displacement of foundation pit, the internal force of the structure, the surface layer stress and damaged form are reasonable. This does not only provide a strong basis for the optimum design of the foundation pit, but also provide a scientific guidance for engineering application.


2011 ◽  
Vol 243-249 ◽  
pp. 2338-2344
Author(s):  
Qing Yuan Li ◽  
Yang Wang

Taking deep excavation engineering in North Region of Senlin Park Station of Beijing Olympic Subway branch as engineering background, deformation law of enclosure structure of deep excavation are studied by the in-situ monitoring means .It shows that the maximum horizontal displacement of retaining pile is closely related with excavation depth and time. When the deep foundation pit is excavated to a certain depth, and steel brace hasn’t been erected, horizontal displacement of the pile tops is maximum. The location of the maximum horizontal displacement shifts down with foundation pit excavation and steel brace erection. With steel brace application, steel axis force decrease, so steel brace can effectively control horizontal displacements of retaining pile and internal force of steel in the pile. In addition, temperature has a certain effect to axis force of steel brace.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Huifen Liu ◽  
Kezeng Li ◽  
Jianqiang Wang ◽  
Chunxiang Cheng

Based on the deep foundation pit project of Laoguancun station of Wuhan rail transit line 16 and according to the engineering characteristics of the construction conditions and the site surrounding the environment, the method of combining field monitoring and finite element numerical simulation is adopted to analyze the law of stress and deformation of the deep foundation pit during excavation and support construction; it includes the horizontal displacement of the underground diaphragm wall, supporting axial force, and the ground surface settlement, which can be compared with measured data. Finally, some suggestions for monitoring and construction of the deep foundation pit in the subway station have been put forward and have certain reference value and practical guiding significance for the design and construction of similar engineering projects. The deformation monitoring of the retaining structure at the middle of the long side of the foundation pit should be strengthened during the construction process.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhongjing Hu ◽  
Qingbiao Wang ◽  
Shuo Yang ◽  
Zhenyue Shi ◽  
Bo Liu ◽  
...  

Advancing urbanization in China requires large-scale high-rise construction and underground transportation projects. Consequently, there is an increasing number of deep foundation pits adjacent to water bodies, and accidents occur frequently. This study uses a numerical simulation method to study the stability of the deep foundation pit near water based on the Biot three-dimensional seepage-stress coupling model, with the open-cut section on the south bank of the Jinan Yellow River Tunnel Project as the engineering field test. This indicates the following: (1) the maximum horizontal displacement of the diaphragm wall occurred in the fifth excavation stage, and a horizontal brace effectively controlled the inward horizontal displacement of the foundation pit; (2) considering the effect of seepage in the soft soil foundation, the maximum vertical displacement of the ground surface at each excavation stage occurred adjacent to the underground continuous wall. As the depth of the foundation pit increased, the vertical surface settlement decreases gradually in the direction away from the excavation face; (3) considering the seepage conditions, within each interval of excavation of the foundation pit, the horizontal displacement of the continuous underground wall and ground settlement declined; and (4) the numerical simulation and field monitoring data were in good agreement. Under the conditions of accurate model simplification and parameter selection, numerical simulations can adequately forecast conditions of the actual project.


2014 ◽  
Vol 638-640 ◽  
pp. 614-619
Author(s):  
Bo Liu ◽  
Qing Nan Liu ◽  
Yi Yan Zhao ◽  
Bing Hui Chen

Dismantling the inner support of deep foundation pit is a risk point.It is of great importance to guarantee the safety of foundation pit when removing the inner support, and the deformation monitoring and analysis in the process of dismantling inner support is crucial. In this paper, a super deep foundation pit engineering as the research background.Through monitoring and analyzing the law of a deep horizontal displacement of the supporting structure,ground settlement, vertical settlement and axial force of support in the process of support demolition,which can be obtained that: the settlement of surface ground around the foundation shows spatial and temporal clearly and the distribution of deep horizontal displacement of supporting structure is similar to the parabolic which the maximum point constant upward shift with supporting continuous removed.Soil pressure of supporting shared with support removing process is changing, and the earth pressures support sharing is increasing. From the monitoring results, the demolition scheme is reasonable and effective and meets the requirements of design and environment.


2011 ◽  
Vol 243-249 ◽  
pp. 546-551
Author(s):  
Hua Zhi Zhang ◽  
Yi Fang Feng

Taking Jiyu Bridge Station of Wuhan Metro Project as example, the deformation characteristics of supporting system of deep foundation pit was studied by means of numerical simulation (FLAC3D) in consideration of construction order. The deformation fields of different excavation depths of diaphram wall were obtained and analyzed in order to gain the maximum horizontal displacement value and settlement value. By comparison with the monitoring data, the simulation results can basically reflect the deformation characteristics. Moreover, the simulation results showed that the application of diaphram wall was feasible for foundation pit supporting in Jiyu Bridge Station, meanwhile, the results can be based on to guide the construction.


2012 ◽  
Vol 594-597 ◽  
pp. 2906-2914
Author(s):  
Chang Wen Chen

On the basis of a typical engineering, a foundation of soil nailing walls supporting simulation model of soil nailing on the structure of the excavation is established with FLAC, the construction process of the supporting structure is analyzed in the dynamic simulation. The deformation characteristics of the supporting structure are analyzed during the construction process, the law of the supporting body deformation with the difference of excavation steps is summarized. The situ test data of the deep foundation horizontal displacement and vertical displacement are obtained by testing in situ. Some useful conclusions are summarized by comparative analyzing the numerical simulation value and situ test data, providing guidance for the design and construction of the pit soil nailing wall.


2021 ◽  
Vol 283 ◽  
pp. 01046
Author(s):  
Zhang Yu ◽  
Yu Li ◽  
Liu Weichao

The foundation pit engineering is a work with large amount of use and high difficulty coefficient. It is necessary to ensure the deformation of soil in the control range and the safety of the whole structure of the foundation pit. In this paper, the foundation pit support project in Shijiazhuang City, Hebei Province is taken as the research object, and the numerical analysis method is used to simulate the pile-anchor support in the First Section of the fourth section of the foundation pit. In this paper, the horizontal displacement value of deep foundation pit and the settlement value of the top edge of foundation pit are analyzed, It provides reference for future projects.


2014 ◽  
Vol 580-583 ◽  
pp. 636-640 ◽  
Author(s):  
Xu Tao Zhang ◽  
Qiang Yong Zhang ◽  
Chao Wang ◽  
You Fa Wang

The horizontal displacement of pit top and horizontal displacement in deep soil of underground garage deep foundation pit in Radio and TV centre of Shandong province was analyzed. Combing the deformation control value of foundation pit, we thought that the supporting structure was safe and reliable. The supporting structure could not only meet the strength requirements but also meet the deformation control requirements. This deep foundation pit was a successful case under complex conditions. Analyzing the variation rules between monitoring data and construction time, the instructive conclusions were obtained. The deformation of foundation pit external corner was largest. The external corner should be avoided in foundation pit. The dynamic loads around foundation pit had a great influence on the safety and stability of pit. The rainfall was disadvantage factors, so the construction of foundation pit should keep away from the rainy season. The foundation pit floor could limit soil deformation and improve the safety of pit. The pit floor should be constructed as early as possible.


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