The Analysis on the Deformation Predition of Pile-Anchor Retaining Structure in Deep Foundation Pit in Kunming

2012 ◽  
Vol 166-169 ◽  
pp. 1222-1225 ◽  
Author(s):  
Yin Hui Chen ◽  
Yu Wen Wang
Keyword(s):  
Horizontal Displacement ◽  
Deformation Characteristics ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Information Construction ◽  
Practical Engineering ◽  
Important Means

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.

Effect of Staged Excavation on Retaining Structure in Soft Soil Area

2012 ◽  
Vol 170-173 ◽  
pp. 633-636 ◽  
Author(s):  
Jie Liu ◽  
Xin Guang Xu
Keyword(s):  
Soft Soil ◽  
Horizontal Displacement ◽  
Structure Type ◽  
Operating Conditions ◽  
Deep Soil ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Geological Conditions

Based on a deep foundation pit in Tianjin, the authors introduced the retaining structure type, surrounding conditions, and the geological conditions of proposed field. According to the engineering characteristics, the excavation was divided into three typical operating conditions. Based on the monitoring of staged excavation of deep foundation pit, analysis on horizontal displacement, deep soil displacement, column settlement and bracing axial force was carried out. The general rules of the deformation and internal force of retaining structures induced by staged excavation were given, which will provide the references for similar engineering.

Study on the Deformation Characteristics of Supporting System of Deep Foundation Pit in Subway Station Construction

2011 ◽  
Vol 243-249 ◽  
pp. 546-551
Author(s):  
Hua Zhi Zhang ◽  
Yi Fang Feng
Keyword(s):  
Numerical Simulation ◽  
Horizontal Displacement ◽  
Subway Station ◽  
Deformation Characteristics ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Supporting System ◽  
Simulation Results ◽  
Metro Project

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.

Research on Deformation Control of Anchor Bolt Supporting Red Clay Deep Foundation Pit

2013 ◽  
Vol 639-640 ◽  
pp. 619-624
Author(s):  
Yong Liang Deng ◽  
Qi Ming Li ◽  
Ying Lu
Keyword(s):  
Lateral Wall ◽  
Horizontal Displacement ◽  
Deformation Characteristics ◽  
Red Clay ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Anchor Bolt ◽  
Deformation Control ◽  
Finite Element Software

In order to study the deformation characteristics of red clay deep foundation pit, the horizontal displacement of lateral wall and the subsidence of surrounding surface were analysed in the step-by-step excavation of red clay deep foundation pit in the construction process. Using finite element software and D-P model, the numerical simulation of a deep foundation project was done. On this basis of differentiated models, the deformation characteristics of different support schemes were further analysed. This study indicates that the spacing of anchor bolt affects the deformation most, followed by the length of anchor bolt and pre-stress. The result shows that selecting a rational scheme for design and construction according to special conditions is important, which can not only guarantee the foundation pit safety, but also save the engineering cost．

Mechanical Analysis of Enclosure Pile under Different Constraints

2011 ◽  
Vol 90-93 ◽  
pp. 485-489
Author(s):  
Li Guo ◽  
Peng Li He ◽  
Guang Jun Zhang
Keyword(s):  
Mechanical Analysis ◽  
Subway Station ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Cantilever Structure ◽  
Reinforcement Measures

The enclosure pile is extensively used as retaining structure in the foundation pit excavation. And it is always combined with other reinforcement measures. So it is unreasonable to a certain degree that the enclosure pile is analyzed as cantilever structure. Taken the deep foundation pit of a subway station in Hefei for instance, the effect of other reinforcement measures on restrained conditions of enclosure piles in the paper was taken into account. And the behavior of enclosure pile under various restrained conditions was analyzed. Based on that, some helpful suggestions for practical retaining structure of foundation pit were put forward.

scholarly journals Study on Flexural Bearing Capacity Calculation Method of Enclosure Pile with Partial Excision in Deep Foundation Pit

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
Jin Li
Keyword(s):  
Flexural Strength ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Theoretical Derivation ◽  
Deep Foundation Pit ◽  
Practical Engineering ◽  
Capacity Calculation ◽  
Partial Excision

During deep foundation pit construction, the structural clearance intrusion, which is caused by the complex formation conditions and the inefficient drilling equipment, is usually detected due to the vertical deviation of piles. To meet construction requirements, pile parts intruding into the structural clearance are supposed to be excised. However, the sectional flexural strength of the pile is bound to decrease with partial excision, which would reduce the bearing capacity of the enclosing structure during construction. In this paper, a theoretical derivation of the normal sectional flexural strength of the partially excised circular pile is proposed. The derivation adopts the assumption of the plane section and steel ring equivalence and can be solved by the bisection method. Furthermore, the calculation method is applied to the pile evaluation of a practical engineering; also, the method is verified by the numerical method. The application results show that the excision of rebar and pile’s sectional area will cause a rapid linear decline in the sectional flexural strength. After excising 18 cm radial thickness of the circular pile (ϕ800 mm) and 6 longitudinal rebars, the sectional flexural strength of the pile decreases to 58% from the origin, which cannot meet the support requirement. The analysis indicates that pile reinforcements must be carried out to maintain the construction safety.

Analysis on the Design and Application of Prestressed Concrete Supporting Piles

2010 ◽  
Vol 44-47 ◽  
pp. 173-176
Author(s):  
Dong Ming Yu ◽  
Zhi Qin Liu ◽  
Feng Guang Chen
Keyword(s):  
Prestressed Concrete ◽  
Deep Foundation ◽  
Engineering Project ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Concrete Piles ◽  
Adjacent Building ◽  
Practical Engineering ◽  
Concrete Materials ◽  
Actual Settlement

The supporting piles of deep foundation pits are usually made in reinforced concrete materials and rarely in prestressed concrete materials. But prestressed concrete materials have higher stiffness and less deformation and are suitable for controlling displacements or settlements. So, in this paper a practical engineering project as an example, the prestressed concrete supporting piles of the deep foundation pit are calculated and designed. Then, the settlement and inclination of the building adjacent the foundation pit with the prestressed concrete piles are calculated in the numerical software, FLAC. The results calculated in FLAC are compared with the actual settlement and inclination of the adjacent building during the foundation pit is excavated. The comparison confirms the feasibility of the supporting structure. This is a useful trial on the design of the prestressed concrete supporting piles.

scholarly journals Optimization Analysis of Deformation of Underlying Tunnel in Dewatering and Excavation of Phreatic Aquifer

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Jing Wang ◽  
Pengcheng Wang ◽  
Wenda Wang ◽  
Shouqiang Zhou ◽  
Xiang Fang
Keyword(s):  
Lateral Displacement ◽  
Beam Theory ◽  
Layer By Layer ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Deep Foundation Pit ◽  
Maximum Deformation ◽  
Phreatic Aquifer ◽  
Deformation Law

This paper theoretically analyzed the deformation law of the underlying tunnel caused by dewatering and excavation of deep foundation pit in the phreatic aquifer area, which is based on the Mindlin solution and the double-sided elastic foundation beam theory, and used the finite difference method and the fluid-solid coupling principle to conduct three-dimensional numerical simulation of dewatering and excavation of deep foundation pit with fluid-solid coupling by using FLAC3D5.00. This research shows that the layered and segmented excavation method from the middle to the end by dewatering the skip layer has a better effect on optimizing the deformation of the underlying tunnel through the simulation of three excavation methods and two dewatering schemes crossing each other, which is about 2.5% less than the layer-by-layer dewatering scheme. In addition, the deformation law of the simulated value is the same as the theoretical value, and the simulated value is slightly larger than the theoretical value. Underlying tunnel only just exists vertical deformation at the direct center of the foundation pit, and the maximum deformation is about 3.054 mm under the dewatering well of the jumping layer and W3. With the dewatering of jumping layer and the third excavation mode (W3), underlying tunnel only just exists lateral displacement at the position where is the retaining structure, and the maximum displacement is 1.606 mm.

Research on Deformation Law of Deep Excavation Supporting Structures in Beijing Metro Station

2011 ◽  
Vol 243-249 ◽  
pp. 2338-2344
Author(s):  
Qing Yuan Li ◽  
Yang Wang
Keyword(s):  
Horizontal Displacement ◽  
Internal Force ◽  
In Situ Monitoring ◽  
Deep Excavation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Metro Station ◽  
Deep Foundation Pit ◽  
Deformation Law

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.

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