The Influence of Engineering Pile on the Bottom Upheaval of Foundation Pit

2012 ◽  
Vol 193-194 ◽  
pp. 624-632
Author(s):  
Xi Zhen Zhang ◽  
Quan Mei Gong ◽  
Shun Hua Zhou
Keyword(s):  
Element Model ◽  
Correction Method ◽  
Inhibitory Effect ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Pile Spacing ◽  
Deformation Control ◽  
Pile Diameter ◽  
Pile Length

In foundation pit engineering, the presence of pile plays an important role on the pit stability and deformation control. The bottom upheaval of deep foundation pit is a key criterion of judging the foundation stability and deformation. This paper built the 3D finite element model to analyze the influence of different factors (pile diameter, pile length and pile spacing) on the bottom upheaval, and concluded that: when pile length and pile spacing is constant, changing the pile diameter can hardly affect the bottom upheaval; as the pile length increased, the inhibitory effect to the bottom upheaval grew stronger with a gradually decreased growth rate; increasing pile spacing can significantly reduce the bottom upheaval, and the smaller the pile spacing, the smaller the upheaval. The concept of upheaval inhibition rate was defined to evaluate the influence of different factors of pile layout on the bottom upheaval. A correction method of calculating the bottom upheaval of foundation pit with engineering pile was proposed. An engineering instance of Shanghai Natural History Museum foundation pit was studied, and the result showed that the bottom upheaval calculated by the correction method is less than the upheaval calculated by method of residual stress, which was more close to the monitoring data. The influence of engineering pile on bottom upheaval of foundation pit should not be neglected where a large number of piles were present in deep foundation pit.

Numerical Analysis of a Pile-Anchor Retaining Structure of Deep Foundation Pit Engineering

2014 ◽  
Vol 638-640 ◽  
pp. 496-502
Author(s):  
Ying Wang ◽  
Jiang Bo Shi
Keyword(s):  
Earth Pressure ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Deformation Control ◽  
Maximum Value ◽  
Negative Moment ◽  
Dip Angle ◽  
Pile Length

Based on a deep foundation pit engineering of Tangshan, considering the interaction of pile-anchor-soil, the finite difference software FLAC3D is adopted in this paper to simulate and analyze the effect of dip angle of anchor and the embedded depth of pile on the horizontal displacement and the variation laws of earth pressure, horizontal displacement of pile with the process of excavation. The results show that the maximum value of horizontal displacement and positive moment of pile appear in 0.85H (H stands for the depth of excavation) and the negative moment appears in 1.3H after the excavation; the maximum value of active and passive earth pressure appear in 1.3H rather than the bottom in the range of pile length; the requirements of deformation control and overall stability of foundation pit can be satisfied with 0.5H which as the embedded depth of the pile, and the dip angle of anchor is appropriate when it ranges from 5°to 25°but less than 30°.

Determination of Spacing between Anchored Piles in Row for Deep Foundation Pit

2012 ◽  
Vol 204-208 ◽  
pp. 2736-2739
Author(s):  
Guang Qian Du ◽  
Shi Jie Wang ◽  
Yan Ting Qin ◽  
Chang Zhi Zhu
Keyword(s):  
Strength Criterion ◽  
Strength Analysis ◽  
Soil Arching ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Pile Spacing ◽  
Soil Arch ◽  
Uniformly Distributed Loads

Based on the pile - anchor structure soil between piles,the unified strength theory is introdued in the strength analysis of soil arching between the piles, and parabolic soil arching computational model is uniformly distributed loads ,which are given to meet the soil between piles arch static equilibrium conditions and intensity of conditions , pile spacing formula. Compared with calculations based on the pile spacing of the Mohr-Coulomb strength criterion , the proposed method can consider the contribution of the intermediate principal stress on the strength of the soil arch , the results are more in line with the actual characters of the supporting structure .

Research on Seepage Characteristics of Deep Cut Canal under Dewatering Well

2013 ◽  
Vol 438-439 ◽  
pp. 588-592
Author(s):  
Kai Yun Yang ◽  
Xiang Yu Li ◽  
Lin Hao Li ◽  
Quan Long Li
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Saturation Line ◽  
Deep Foundation ◽  
Seepage Field ◽  
Foundation Pit ◽  
Element Analysis ◽  
Deep Foundation Pit ◽  
Geological Conditions ◽  
Seepage Characteristics

In view of the problems of complex geological conditions with high underground water level, large permeability coefficient of soil and the presence of large seepage hazard of deep cut canal and deep foundation pit project of South-to-North Water Transfer Project, China, research on seepage characteristics of digging canals under dewatering well is carried out by finite element analysis, and the FORTRAN procedure is programmed. The three-dimensional finite element model of a digging canal is built, and the seepage field of the different conditions of the canal is simulated, the water head distribution, saturation line and leakages are obtained, and the rules and characteristics of steady seepage field under design impervious system are analyzed. The results indicate that the method can exactly determine the key overflow point and saturation line of canal, and well predict seepage field in canal. The results should be of guiding significance to design and construct retaining engineering in deep cut canal and deep foundation pit.

scholarly journals Investigation of the Axial Force Compensation and Deformation Control Effect of Servo Steel Struts in a Deep Foundation Pit Excavation in Soft Clay

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Honggui Di ◽  
Huiji Guo ◽  
Shunhua Zhou ◽  
Jinming Chen ◽  
Lu Wen
Keyword(s):  
Axial Force ◽  
Soft Soil ◽  
Control Effect ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Deformation Control ◽  
Retaining Structure ◽  
Hydraulic Servo ◽  
Ordinary Steel

This study presents a comparative analysis of the deformation control effect of the hydraulic servo steel struts and ordinary steel struts of a foundation pit based on the measured axial force of the steel struts, lateral wall deflection, and ground surface settlement due to pit excavation. The results indicate that ordinary steel struts installed via axial preloading exhibit a disadvantageous axial force loss with a maximum value equal to 86.7% of the axial preloading force. When compared with ordinary steel struts, the hydraulic servo steel strut exhibits a superior supporting effect. The hydraulic servo steel strut adjusts the axial force in real time based on the deformation of the retaining structure and the axial force of the struts. Thus, the ratio of maximum lateral deflection to the excavation depth of a deep foundation pit in soft soil is less than 0.3%. Concrete struts undergo unsupported exposure during the excavation process, leading to sharply increasing deformation of the retaining structure. Therefore, regarding a foundation pit with strict requirements for deformation control, the use of hydraulic servo steel struts rather than concrete struts is recommended.

The Stability Analysis of Deep Foundation Pit Engineering Support and Field Testing Research

2011 ◽  
Vol 105-107 ◽  
pp. 1456-1459
Author(s):  
Xiang Dong Zhang ◽  
Zhi Liu ◽  
Xi Jun Liu
Keyword(s):  
Field Testing ◽  
Element Model ◽  
Transverse Displacement ◽  
Simulation Design ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Displacement Effect ◽  
Deep Foundation Pit ◽  
Supporting Structure ◽  
The Stability

In order to study the foundation pit supporting structure displacement of the change rule and different parameters on the transverse displacement effect of pile. My research based on supporting structure engineering of Shenyang Washington. We use the software ADINA as a research tools to establish a finite element model. We simulated and analyzed the displacement with and without anchor. Results show that adding anchor supporting played a very good supporting effect, and the simulation results and actual test results compared and analyzed proved reasonable and simulation design scheme was feasible, this excavation has some guidance for the engineering and a certain reference for similar deep foundation pit bracing. [1]

Construction Monitoring and Post Analysis of a Deep Foundation Pit

2012 ◽  
Vol 482-484 ◽  
pp. 52-57
Author(s):  
Rui Mei Zhang ◽  
Jing Cao ◽  
Zhi Gang Song
Keyword(s):  
Design Theory ◽  
Safety Management ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Construction Monitoring ◽  
Deep Foundation Pit ◽  
Deformation Control ◽  
Supporting Structure ◽  
Safety Assurance ◽  
Pressure Water

Construction monitoring of excavation engineering is important in verifying design theory and guiding field construction. It plays a significant role in safety management of construction, deformation control of supporting structure and safety assurance of surrounding buildings. A construction monitoring of a deep foundation pit in urban village is carried out. The observation datum are reviewed and analyzed. It is found that the process of high pressure water-rushed hole by single tube and poor piling result in silt are two main reasons for large deformation observed in supporting structure and surrounding ground.

Basal Heave Stability Analysis of Deep Foundation Pit in Soft Soil

2013 ◽  
Vol 405-408 ◽  
pp. 233-236
Author(s):  
De Sen Kong ◽  
Yan Qing Men
Keyword(s):  
Stability Analysis ◽  
Soft Soil ◽  
Element Model ◽  
Critical Value ◽  
Critical Conditions ◽  
Plastic Range ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Basal Heave

In order to avoid the limitations in traditional methods of basal heave stability analysis for deep foundation pit, numerical analysis was adopted by establishing a two-dimensional elasto-plastic finite element model. Resistant heave stability safety factor was calculated using the fitting formula acquired from the simulated results, and then the upheaval value and plastic range under critical conditions were studied. The results show that the soil stress will be redistributed with the increasing of excavation depth until upheaval damage taken place. The upheaval value will be larger, the plastic range will be greater, and the basal heave stability will be worse with the decreasing of plastic parameters. Meanwhile, the basal upheaval peak position will transform gradually from excavation center to diaphragm neighborhood with the decreasing of plastic parameters. There is a critical value associated with supporting parameters for soil plastic parameters and the possibility of upheaval destruction increases significantly if the plastic parameters are less than the critical value.

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．

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