Control of Artificial Recharge on Foundation Pit Deformation due to Dewatering

2012 ◽  
Vol 594-597 ◽  
pp. 1901-1904
Author(s):  
Hua Yuan ◽  
Yan Hong
Keyword(s):  
Artificial Recharge ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deformation Control ◽  
Adjacent Building ◽  
The Difference ◽  
Prevention Method ◽  
Deep Foundation Excavation ◽  
Controlling Measures ◽  
Control Principle

In this paper, the currently available, feasible controlling measures for the deformation of foundation excavation and its surrounding environment are summarized systemically, which is mainly embodied in pit collapse, adjacent building differential settlement as well as underground pipeline cracking. Then first from the two aspects: artificial recharge used as prevention method and management measure separately, the paper illustrates the control principle, operation method and matters needing attention during artificial recharge. In addition, the difference between pumping well and recharge well are discusses. The research results will provide direction for the deformation control of deep foundation excavation and the operation of artificial recharge.

Weight Analysis of Accident Factors in Deep Foundation Excavation Based on Analytic Hierarchy Process

2014 ◽  
Vol 711 ◽  
pp. 529-534
Author(s):  
Zi Sheng Yang ◽  
Jun Xia Liu ◽  
Yi Ren Wang
Keyword(s):  
Analytic Hierarchy Process ◽  
Deep Foundation ◽  
Accident Rate ◽  
Foundation Pit ◽  
Analytic Hierarchy ◽  
Weight Analysis ◽  
Deep Foundation Excavation ◽  
Hierarchy Process ◽  
Factor Set ◽  
Design Construction

For the past few years, great development has been achieved in deep foundation excavation. However, due to foundation excavation’s locality, individual diversity, complexity and uncertainty, the probability of accidents in foundation pit engineering tends to be greater than that in main works, and the accident rate may even reach about 20%, which makes the study on factors leading to foundation excavation accidents quite necessary and meaningful. By use of Analytic Hierarchy Process (AHP), this paper has figured out the ratio (weight) of the investigation, design, construction and other factors leading to foundation excavation accidents to the whole factor set, which is of great guiding significance to the study on prevention and treatment of foundation excavation accidents in future.

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.

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.

scholarly journals Impact of High-Rise Buildings Construction Process on Adjacent Tunnels

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Haifeng Guo ◽  
Aijun Yao ◽  
Jiantao Zhang ◽  
Yijun Zhou ◽  
Yanfei Guo
Keyword(s):  
Earth Pressure ◽  
Scale Model ◽  
Construction Process ◽  
Deep Foundation ◽  
Deep Side ◽  
Foundation Pit ◽  
High Rise ◽  
Shallow Side ◽  
Deep Foundation Excavation ◽  
The Impact

The demand for buildings constructed along subway lines is increasing, and analysis of the impact of foundation excavation and building construction on adjacent tunnels is critical. This study investigated the variation law of tunnel deformation and surrounding earth pressure on an existing tunnel resulting from deep foundation excavation and the load of buildings. Four groups of scale model tests and corresponding numerical simulation calculations were conducted in four different modes: over unloading-loading, shallow-side unloading-loading, middle-side unloading-loading, and deep-side unloading-loading, which are according to the different relative position of the foundation pit and the tunnel. The results show that when the tunnel stretches across different areas, corresponding deformation occurs owing to the different mechanical mechanisms during excavation and loading. The results can provide evidence for the further study on the impact of adjacent construction process on the tunnels.

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.

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°.

Manufacturing and Hoisting Technology for Reinforcement Cage of Deep Foundation Excavation Bored Piles

2014 ◽  
Vol 1044-1045 ◽  
pp. 633-637 ◽  
Author(s):  
Xin Zhou ◽  
Guang Xiu Fang ◽  
Ping Zhang ◽  
Yuan Qing Leng
Keyword(s):  
Steel Reinforcement ◽  
Detailed Calculation ◽  
Construction Technology ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Element Analysis ◽  
Bored Pile ◽  
Steel Processing ◽  
Deep Foundation Excavation ◽  
Set Up

Combined with the Beijing Business Center (CBD) core district Z14 plots commercial finance project (hereinafter referred to as the "CBD project") foundation pit construction, introduces the deep foundation pit of bored pile reinforcement cage fabrication and erection construction technology. In the construction process, through the site set up a special steel processing and production platform, the localization of the flange and other measures to solve the steel reinforcement cage positioning and connection construction difficulties. Combining the engineering fact, detailed calculation process of lifting steel cage hanging position, lifting machinery and hoisting rigging selection, and through the ANSYS software of finite element analysis and put forward specific measures to ensure the quality of steel reinforcement cage.

scholarly journals A Study on the Mechanisms of Interaction between Deep Foundation Pits and the Pile Foundations of Adjacent Skewed Arches as well as Methods for Deformation Control

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Kai Cui ◽  
Jun Feng ◽  
Chengyong Zhu
Keyword(s):  
Retaining Walls ◽  
Pile Foundations ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Reinforcement Scheme ◽  
Deformation Control ◽  
Complex Interactions ◽  
Pile Caps ◽  
Heavy Loads ◽  
Computational Analyses

The construction of deep foundation pits is characterized by heavy loads on pile foundations, complex interactions between the foundation pit and pile foundations, and stringent requirements for deformation control. In this work, FLAC3D was used to perform computational analyses on the displacement responses of pile caps and the retaining walls of foundation pits in a variety of cases and reinforcement schemes. The computational results indicate that the piles of skewed arches interact with the retaining walls of the foundation pits through soil masses. We also revealed the mechanism by which deep foundation pits interacted with the pile foundations of adjacent skewed arches. Based on the mechanisms of interaction between foundation pit excavations and the piles of skewed arches, we proposed three reinforcement schemes for controlling the deformations associated with these interactions. The arched wall reinforcement scheme could provide a satisfactory result in terms of the control of horizontal displacements in the pile foundations and project costs.

scholarly journals Study on Deformation and Stability of Rock-Like Materials Retaining Structure during Collaborative Construction of Super-Adjacent Underground Project

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Hongfu Qu ◽  
Lihua Wang ◽  
Chunlei Feng ◽  
Hualao Wang ◽  
Xuan Zhang
Keyword(s):  
Limit Equilibrium ◽  
Adjacent Area ◽  
Underground Engineering ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Retaining Structures ◽  
Retaining Structure ◽  
Collaborative Construction ◽  
Measured Deformation ◽  
The Difference

The collaborative construction of undercrossing tunneling of Gongchang Road and the adjacent Metro Line 6 extension station section in Shenzhen is difficult and of high risk. In view of these characteristics, this paper studied the deformation and stability of rock-like material retaining structures in the process of underground engineering collaboration by combining the measured deformation data and the circular slide theory based on the limit equilibrium method. The results show that due to the difference between the supporting systems of rock-like materials on both sides and other reasons, the upper part of the retaining structure and the limited soil in the adjacent area tilt greatly to one side at the same time, and the surface settlement in the limited soil area also increases with the increase of the excavation depth of the foundation pit. On the basis of measured deformation data analysis, the mechanical model for calculating the stability concerning the relationship between the adjacent distance L of the deep foundation pit and the vertical distance D ′ between the lowest support of the foundation pit and the bottom of retaining structures was established. Then, the calculation formula for the against basal heave stability covering different adjacent degrees was established. Besides, the applicability of the calculation method was verified by combining it with the actual engineering and related prediction theories, which further proves that the research results have certain theoretical value and engineering significance, and can provide a reference for the rock-like material retaining structures design and stability analysis of similar projects.

Research on the Influence of Deep Foundation Pit Excavation on Neighboring Buildings

2014 ◽  
Vol 1055 ◽  
pp. 131-134
Author(s):  
Wen Jing Chai
Keyword(s):  
Construction Projects ◽  
Deep Excavation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Excavation Process ◽  
Technological Level ◽  
Deep Foundation Excavation ◽  
Management Staff ◽  
The Impact

With the development of society and economy, China's investment in construction projects is increasing, which requires the construction and management staff to improve their professional level, to develop a more scientific construction plan to ensure construction quality, and ultimately to the construction goal. Especially in deep foundation excavation process, it not only needs to upgrade the technological level of the excavation, but also needs to enhance the impact of researches on the approaching buildings to make the appropriate preparations to reduce adverse effects on the surrounding buildings, which meets the actual needs of construction, to ensure building construction safety. By exploring the impact of deep excavation on adjacent buildings, the paper makes the construction workers deeply understand the importance of deep foundation construction work.

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