Study on Effect of Excavation Depth on Internal Force of Retaining Structure of Arc Row Piles with Arc Ring Beam on the Pile Top

2014 ◽  
Vol 919-921 ◽  
pp. 762-768
Author(s):  
Zhi Wei Zhang ◽  
Rong Gui Deng ◽  
Ze Shuo Chen

In order to control deformation of foundation pit effectively and guarantee safety of building around, utilizing the stress characteristics of arch, use the new spatial retaining structure of arc row piles with arc ring beam on the pile top. The arc ring beam can provide constraint to pile top, so internal force of pile body distribution is uniform, and improve the integrity stability of piles. The ring beam with compression mainly can give use of high compression capability of concrete. According to the high order statically indeterminate characteristics of the retaining structure, calculation model of ring beam and pile respectively is established by the redundant forces between beam and pile top. By using deformation compatibility to set up flexibility equation of the retaining structure, and solve the redundant forces, then calculate the internal force and displacement of ring beam and piles. Through calculating the practical engineering, research the effect of excavation depth on internal force and displacement of piles and the arc ring beam on the pile top.

2012 ◽  
Vol 204-208 ◽  
pp. 72-78
Author(s):  
Yu Wang ◽  
Yan Ting Yang ◽  
Feng Yu ◽  
Guang Lei Hu

Double-row piles retaining structure has been widely used in the project now, but the stress mechanism of double-row pile is more complex; Its internal force and deformation are affected by many factors. Understanding and mastering its effects has an important significance for the design and the optimization of double-row pile supporting structure. According to the comparison of the measured data and theoretical calculation about original support scheme and optimized support plan and combined with the soil test data, this paper takes the Jinan Cultural Arts Center(Theatre) stage bin foundation pit as an example to analyse the main effects of optimization design about double-pile supporting structure. The results show that soil shear strength, soil arch effect, influence of CFG composite foundation, pile-beam synergy effect and space effect of foundation pit play an important role for optimization design about double-pile supporting structure.


2014 ◽  
Vol 638-640 ◽  
pp. 884-887
Author(s):  
Yong Gang Du ◽  
Jing Cao ◽  
Zu De Ding

Based on the project of a foundation pit engineering adjacent to existing tunnel of Kunming metro line 1, a 3D calculation model is established in consideration the interaction of foundation pit support structures, tunnel structure and soil. In this paper, the authors have simulated the foundation pit excavation process in three conditions, and analyzed the changing laws of the lateral displacement and internal force of the tunnel induced by adjacent excavation under different conditions. Calculation results show that the distributions and the values of the displacement and internal force of the tunnel are obviously different under three different construction technologies, and the “jump dig” is the optimum excavation scheme due to the restriction in the excavation of foundation pit, and the lateral deformation of tunnel structure is smallest in this condition. The conclusion can provide a theoretical basis for similar excavation engineering construction.


2011 ◽  
Vol 90-93 ◽  
pp. 446-452
Author(s):  
Chang Jie Xu ◽  
Zhi Yuan Luo

For the current simplified calculation of pile-brace support structure can not calculate the displacements of pile and brace, the authors try to start from the deflection differential equation of beam on elastic foundation, considering the deformation compatibility of pile and brace, and obtains the internal forces and displacements of pile by using Finite Difference Method. Meanwhile, Finite Element Method is used to analyze and calculate the horizontal displacements of pile. The results show that the values obtained by this article are closer to the measured values than that obtained by Finite Element Method. The method is accurate, reliable and simple. Besides, this author also analysis the different horizontal displacements of pile under different parameter conditions of support structure, which can provide some valuable suggestions for the design of foundation pit.


2021 ◽  
Vol 248 ◽  
pp. 01036
Author(s):  
Xin Wang ◽  
Xie Hui Luo ◽  
Wan xue Long ◽  
Bo Jiang

In order to understand the deformation law and internal force distribution characteristics of the pile-anchor retaining structure in deep foundation pit engineering, the stress of the pile-anchor retaining system in the process of foundation pit excavation was tested by using the distributed optical fiber sensing technology of BOTDA. It uses the supporting pile cloth to set up the strain cable to collect the strain from the excavation process to the stability of the foundation pit, which analyzes the stress and internal force distribution. The results show that the overall deformation of the foundation pit is small and in a stable state. It uses the monitoring strain energy to truly reflect the distribution and transmission law of the pile internal force. It is shown that the bending moment is the maximum at the action position of the anchor cable on the pile anchor structure and 2.5m below the bottom of the pit. The design needs to reinforce the construction of such locations. At the same time, the distribution form of earth pressure calculated in reverse is different from the conventional one. When there are multiple rows of prestressed anchor cables, the earth pressure applied on the support is less than the calculated value of classical earth pressure theory. This pile anchor structure design theory and engineering application has reference value.


2012 ◽  
Vol 170-173 ◽  
pp. 195-198
Author(s):  
Qing Ke Zhu

We established a calculation model for retaining structures with double-row piles by using the midas GTS finite-element software, considering the interaction between pile and soil and adopting the contact element method, on the basis of a practical engineering application. We then determined a reasonable elastic modulus of reinforced soil bodies, thereby enabling the study of the influences of the reinforcement depth and width in the interpile soil on the internal force and displacement of the retaining structure with double-row piles. We present suggestions for reinforcement depth and width. The study results provide valuable reference for engineering design, construction, and cost control.


2012 ◽  
Vol 256-259 ◽  
pp. 507-513
Author(s):  
Shou Ze Cheng ◽  
Wei Hua Wang ◽  
Chang Jie Xu

Incremental method, as one of the practical calculation methods in retaining structure design of foundation pit, has been widely used. When incremental method is applied, the earth pressure, acting on the retaining structure on each incremental step, is considered as static earth pressure. Actually, the state of earth pressure changes constantly with the increase of soil displacement in the process of excavation. This paper introduces the relation of displacement and earth pressure based on the soil stress-strain state, and makes corrections for the earth pressure of the incremental method. By comparing with the measured data of the engineering, the calculation results, which consider earth pressure modification, are in good line with the practical engineering condition. The method in this paper can provide certain reference for related engineering design.


2014 ◽  
Vol 580-583 ◽  
pp. 474-480
Author(s):  
Yan Liu ◽  
Jun Yan Liu ◽  
Tao Liu

In the excavation process of Foundation Pit in Soft Soil area, it will cause the large uplift of stand column, and may cause the instability and failure of foundation pit in case of being serious; but the additional internal force of support system caused by the uplift and sinking of stand column currently has no practical calculation model in the foundation pit design. This article discusses the reason and mechanism for uplift of stand column in the foundation pit, proposes the simplified calculation method of estimating the additional bending moment of inner support through uplift of stand column in allusion to two main influence factors of bottom heave and vertical load caused by the excavation of foundation pit, inversely calculates the permissible additional bending moment of inner support based on this, verifies by combining the monitoring data for uplift of stand column in the actual project, and finally, further proposes the project measures corresponding to the uplift of stand column, hoping to provide beneficial reference for the similar project.


2012 ◽  
Vol 166-169 ◽  
pp. 1222-1225 ◽  
Author(s):  
Yin Hui Chen ◽  
Yu Wen Wang

This article from deformation characteristics of deep foundation pit which support by the pile anchor, then using neural network and Matlab software to establish the time series model to prediction and analysis the deep horizontal displacement of soil. The prediction results show that the overall shape of the curve is similar to "bow” ,and with the depth of excavation the maximum displacement occurred by the beginning of the location of 0.5 m from the surface to move to about half of the excavation depth That is the H/2 up and down position. The results have some reference to the practical engineering in a certain extent, this explain that the prediction is a kind of important means to realize information construction.


2013 ◽  
Vol 477-478 ◽  
pp. 503-508 ◽  
Author(s):  
Shi Min Zhang ◽  
Xing Ming Jia ◽  
Teng Kun Yuan ◽  
Wei Guo Liu ◽  
Yin Jun

The problem always exist in foundation pit engineering that the support axial force can not be regulated in the pit system in real time.According to setting the axial force compensation system,the problem would be solved perfectly and efficiently,realizing the fact control and adjust the support axial force and stability. The axial force compensation system which is constituted by jacks distributed in the pit has been confirmed the significant role to control foundation pit deformation and internal force monitoring combined with practical engineering


2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.


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