Analyses of Earth Pressure on Gridding Concrete Retaining Wall in the Excavation of Deep Foundation Pit in Soft Soil Area

2011 ◽  
Vol 52-54 ◽  
pp. 2181-2186
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu

This paper is mainly to study earth pressure on Gcrw used as a new kind of supporting structures in the excavation of deep foundation pits in soft soil region. On the basis of the simulation of step by step excavation by using big finite element software Abaqus/CAE and considering three-dimension elastoplastic stress state, the characteristics of different earth pressure are systematically discussed upon practical engineering. By comparing simulation results with calculated results based on calculation formula of Rankine Theory, it can be seen that the earth pressure in active zone is different from theoretic active earth pressure and earth pressure at rest while walls and soil in the gridding are regarded as a whole, which is greater than the former and somewhere similar to the latter, the earth pressure in passive zone is bigger than theoretic value of passive earth pressure, it is the tensive force from partition wall that prevent the front wall from overturning. These conclusions will be helpful for design and construction of new retaining wall.

2011 ◽  
Vol 243-249 ◽  
pp. 2266-2270
Author(s):  
Guang Zhu Zhou ◽  
Xu Wei ◽  
Chen Yu

As a new type of building envelope, Gcrw is mainly used for excavation of foundation pit. It can stand by itself without the help of bracing, especially in soft soil area. Its stressed characteristic hasn’t been known yet. By using advanced big finite element software Abaqus/Cae, a simulation was made on model of Gcrw under soil pressure when a foundation pit is dug, while the whole excavation is divided into three continuous independent excavation stages. The result shows that Gcrw is a rather good building envelope, Gcrw and soil in the gridding form an integral earth-retaining structure and keep balance under soil pressure before or behind the structure, and have little displacement in horizontal direction. It is like a gravity-type retaining wall in its entirety, but takes on an elastic characteristic. The soil pressure presents a linear change, but its value is less than the theoretical value of calculation. The front wall of Gcrw, like a sheet, is the main flexural construction element, which is subjected to the pressure from side wall of foundation pit and produce curve deformation. The back wall of Gcrw has little displacement and almost is built in the clay. The partition wall endures the effect of the tensile force, its horizontal deformation increases with the build-in depth’s increasing. The back wall and the partition wall play a very important role in dragging back the front wall, the role of them is similar to a pair of anchor tie. The soil in the gridding not only provides soil pressure, but also can fix the back wall, so it is seen as a part of Gcrw and in favor of the Gcrw’s anti-overturn.


2011 ◽  
Vol 261-263 ◽  
pp. 923-927
Author(s):  
Jian Zhou ◽  
Zi Han Wang

The characters on double-row pile retaining structures are affected significantly by spatial effects. In this paper, double-row pile retaining structures are simulated numerically in three-dimension by finite element software PLAXIS. The behavior differences among piles in different positions around the foundation pit are analyzed. The results show that the deformation and moment are biggest in the middle of long side of the foundation pit. It is suggested that the earth pressure between the rows above the pit bottom is close to active earth pressure.


2011 ◽  
Vol 243-249 ◽  
pp. 2732-2737
Author(s):  
Hong Bo Guo ◽  
Ke Sheng Ding ◽  
Yi Jia Zhang ◽  
Xu Li

The cover reverse construction excavation is one of the important construction methods which is used in digging extra-deep foundation system of underground continuous wall supporting. The earth pressure distribution and deformation is distinct from different construction methods. Even if the Construction methods and computer program is homogeneous, the earth pressure and deformation of the calculated showed various results because of different test parameters and different constitutive models, Through the application of practical engineering, The appropriate calculation parameters and constitutive model are found out in Abaqus program which is suitable for earth pressure and deformation of the diaphragm wall in the soft soil area.


2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Yousheng Deng ◽  
Zhihe Cheng ◽  
Mengzhen Cai ◽  
Yani Sun ◽  
Chengpu Peng

Bamboo is highly renewable and biodegradable with good short-term strength, which meets the requirement for temporal support structures in shallow foundation pits. Based on this, we conducted a laboratory model test on the dentate bamboo micropile support structure combined with environmentally friendly building materials and new type of piles, to explore the stress characteristics, stress change regularity, and the support effect of the system in soft soil foundation pits. The results show that the earth pressure on the pile sides above the excavation surface gradually decreases with an increase in the excavation depth. The bending deformation of the bamboo pile was also significant. The results also show that the earth pressure and the pile strain below the excavation surface change slightly during the excavation process. When the short sides of the foundation pit were loaded, the highest strain was recorded in the piles 4 and 11. A maximum strain of 358.93 με was recorded, and the maximum displacement of the pile in the top part was obtained to be only 2.14 mm. The most subsidence of dentate pile obtained is only 1.88 mm, whereas that of the single-row pile is 2.35 mm. Compared to the traditional single-row pile, the dentate piles can effectively reduce the horizontal deformation as well as the surface subsidence effectively. They can also support more external lateral load, and hence maintain the foundation stability and give better support. The results provide a theoretical basis for ecological bamboo support technology and have great value to be promoted.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yijun Zhou ◽  
Aijun Yao ◽  
Haobo Li ◽  
Xuan Zheng

In order to study the earth pressure and the deformation behavior of the double-row piles in foundation excavation, a large-scale physical model test was introduced to simulate deformation of double-row piles in foundation excavation based on the principle of similarity theory in this paper. Represented by the deep foundation pit engineering of Changchun, the strain and the displacement of the double-row piles and the earth pressure are calculated by the above-mentioned physical model test. Then a numerical simulation has been carried out to validate practicability of the physical model test. The results show that the strain and the displacement of the front-row piles are larger than the back-row piles. The earth pressure of the front-row piles appears to be “right convex,” correcting the specification of the earth pressure and putting forward the coefficient of β. The results in this paper may provide constructive reference for practical engineering.


2022 ◽  
Vol 2148 (1) ◽  
pp. 012051
Author(s):  
Ruibin Yang ◽  
Xinsheng Li ◽  
Dongzhou Xie ◽  
Hongte Meng

Abstract At present, in deep foundation pit engineering, on the one hand, practice is ahead of theory, and on the other hand, theory can not correctly reflect the actual construction process and environmental effects. In order to further study the distribution and change law of earth pressure and internal force of pile body in deep foundation pit pile-anchor supporting system, field monitoring test of earth pressure and pile body reinforcement stress was carried out. The monitoring results show that before excavation, the distribution of earth pressure has a great relationship with the layering of the soil, and it is distributed in sections along the depth. Compared with the theoretical static earth pressure, the measured data of the upper depth is relatively small; after excavation, the overall earth pressure is distributed along the depth in a “z” shape under the non-limiting state. As the excavation progresses, the magnitude of the reduction of the earth pressure varies from place to place, and the magnitude of the decrease of the soil with better properties is not large; after the excavation, the stress and earth pressure of the pile reinforcement correspond to each other, and the distribution is also nonlinear. The existence of anchor tension has an obvious effect on improving the internal force of the pile. The selected earth pressure calculation methods have some discrepancies in the calculation of the earth pressure value of the project, and they need to be further improved. The research in this paper can provide reference and reference for the calculation of earth pressure and support design of pile-anchor supported foundation pit.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zi-Tian Yu ◽  
Heng-Yu Wang ◽  
Wenjun Wang ◽  
Dao-Sheng Ling ◽  
Xue-Dong Zhang ◽  
...  

Excavations near an existing tunnel are often encountered in underground construction. The influence of the excavation on the adjacent tunnels is not yet fully understood. This study presented a centrifugal model test about excavation next to existing tunnels in soft soil foundation. The bending moment of diaphragm wall, surface settlement, tunnel deformation, and earth pressure around the tunnel were mainly studied. The influence of tunnel location is further studied by numerical simulation. During the stabilization stage of foundation pit, the diaphragm walls present convex deformation towards foundation pit, and the surface settlement outside the diaphragm wall appears to be the concave groove type. During the overexcavation stage, the diaphragm walls are almost damaged, and the shear bands are nearly tangent to the tunnels. The displacement of the tunnels and the surface settlement rapidly increase. The deformation of the diaphragm wall and the surface settlement are limited by the existing tunnel. The numerical results indicate that the change of tunnel location has little effect on the retaining wall but an obvious effect on the tunnel itself.


2013 ◽  
Vol 353-356 ◽  
pp. 3598-3605
Author(s):  
Xiao Dong Yi ◽  
Peng Huang ◽  
Zhi Chao Wang

Deep foundation pit supporting in soil-rock areas has been occurred commonly in Dalian. In the dual structure deep foundation pit in which platform is reserved, pile-anchor support as a typical form of foundation pit support, how to play its role effectively and make the design economical and safety is the subject which was explored continuously in recent years. Through a practical engineering case, this paper will use finite element software ABAQUS to simulate the whole process of pit excavation. Simulation results show that the boundary of the dual structure is the key position that caused the “sharp deformation” of the supporting structure. Compared with monitoring data, the results indicate that the reliability of the numerical model and the relevant deformation laws are verified, which can be used for the reference for the design, construction and monitoring of the deep foundation pit support in the similar location.


2015 ◽  
Vol 724 ◽  
pp. 79-83
Author(s):  
Xiao Qin Wang ◽  
Ting Ting Sun

The constitutive relations of soil in the super-large deep foundation pit project and the law of interaction between soil and the support structure were studied. The excavation of the foundation pit was simulated. The coupling of soil and the support structure and the change in earth pressure with the progress of excavation were analyzed, and the scope of influence of foundationsubsidence was obtained.


2014 ◽  
Vol 926-930 ◽  
pp. 712-715
Author(s):  
Li Qiao Cao

After a literature survey, the application of 3D seepage-consolidation coupling FEM model based on Biot theory and Cam-Clay model for simulating deep excavation dewatering in soft soil is studied. A foundation pit in East-China is taken as an example and 3D finite element method is used to simulate the dewatering and excavation. Through the 3D finite element analysis, the three-dimension numerical method can be applied to study the deformation behavior of foundation pit and surrounding soil. The numerical simulation experience and data presented in the paper can be refereed in the design, construction and research of similar projects.


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