Analysis in Stability of Monitoring Network for Deep Foundation Pit Based on Mean Spacing Method

2014 ◽  
Vol 1073-1076 ◽  
pp. 1895-1901
Author(s):  
Xiao Lei Sun ◽  
Wen Chun Zhang ◽  
Wei Dong Li
Keyword(s):  
Monitoring Network ◽  
Control Points ◽  
Population Variance ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Network Information ◽  
F Distribution ◽  
The Stability ◽  
Spacing Method

Based on establishing monitoring network in accordance with the requirements of criterion, monitoring network for deep foundation pit in the people's hospital of jilin province has been taken as research object to collect multi-period network information. Based on free net adjustment method, the combined adjustment has been carried out in multi-period plane network. Choosing displacement variation of two control points as mean spacing in plane network, and using mean spacing method program in MATLAB platform to calculate sample and population variance of observed value, structure F distribution and analyze the stability of monitoring points. The results show that using mean spacing method can rapidly distinguish the stability of monitoring network and points, which offers reliable gist for monitoring project.

Research of Controlling for Pile-Anchor Joint Supporting Structure on Deformation of Deep Foundation Pits

2011 ◽  
Vol 261-263 ◽  
pp. 1809-1813
Author(s):  
Jin Biao Chen ◽  
Qiang Hu ◽  
Yuan Wu Zhou
Keyword(s):  
Soil Properties ◽  
Deformation Mechanism ◽  
Geotechnical Engineering ◽  
Reliability Theory ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Supporting Structure ◽  
Foundation Deformation ◽  
The Stability

The excavation of deep foundation pit is very complex in the field of geotechnical engineering, how to control the deformation of deep foundation pit and protect the environment is of great significance. This paper analyzed the deformation mechanism of pile-anchor joint supporting structure in detail, established a model for deformation controlling based on the reliability theory, and then analyzed the sensitivities of prestressed, pile stiffness, spacing and soil properties to foundation deformation. Combined with an engineering example, this paper verifies the stability and effectiveness of the model for deformation controlling. This study will provide some reference to similar projects.

Monitoring and Analysis on the Supporting Structure for Deep Foundation Pit

2014 ◽  
Vol 580-583 ◽  
pp. 787-790
Author(s):  
Hai Xia Sun ◽  
Ke Zhang ◽  
Si Li Chen
Keyword(s):  
In Situ Monitoring ◽  
Monitoring Data ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Metro Station ◽  
Deep Foundation Pit ◽  
Supporting Structure ◽  
Deformation Features ◽  
The Stability

This article mainly expounds the importance of in-situ monitoring on the construction process of deep foundation pit. Taking the deep foundation pit of some Shenyang metro station for example, the deformation features of the supporting structure and the internal and external of foundation pit is analyzed, according to the monitoring data of the fender pile displacement during the excavation of deep foundation pit. The conclusion is obtained that the timely and accurate in-situ monitoring information is necessary to guaranteeing construction safety. We should pay more attention to the excavation speed and exert the interior support timely during the excavation of foundation pit to avoid large deformation and danger. The analytical results of monitoring data shows that the whole stage of foundation pit excavation is stable and the fender pile with internal supports can guarantee the stability of foundation pit.

Stability on Supporting Structure of Deep Foundation Pit with Infiltration

2012 ◽  
Vol 170-173 ◽  
pp. 223-226 ◽  
Author(s):  
Xue Song Gao ◽  
Jian Jun Dong ◽  
Xu Zhao ◽  
Peng Yang Yin ◽  
Shao Hua Lv
Keyword(s):  
Bending Moment ◽  
Rainfall Infiltration ◽  
Deep Excavation ◽  
Initial State ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Building Foundation ◽  
Internal Forces ◽  
The Stability

The FLAC3D was used to the fluid-solid coupling numerical simulation of considering the initial state of unsaturated to soil for the deep foundation pit engineering under different rainfall infiltration conditions. By comparing the bending moment, the shearing stress and internal forces of support under the infiltration conditions between non-rainfall and rainfall, the paper focus on the stability of deep foundation pit. Research on the stability of deep excavation under rainfall conditions was a useful attempt. From the detail study of the stability of a foundation pit of Qinhuangdao under rainfall infiltration conditions, the paper have drawn some useful conclusion on the design of building foundation pit, which can be the basis of excavation design and construction under rainfall conditions.

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]

Study on Measures to Retain the Deep Foundation Pit for Soil-Rock Composition with Weak Intercalated Layers

2013 ◽  
Vol 405-408 ◽  
pp. 373-377
Author(s):  
Jing Wang ◽  
Feng Ming Sun ◽  
Jin You Chen ◽  
Chang Jie Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Balance Method ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Rock Composition ◽  
Deep Foundation Pit ◽  
Retaining Structure ◽  
Geological Conditions ◽  
The Stability

Aiming at a deep foundation pit in soil-rock composition with weak intercalated layers, in this paper, using the limit-balance method and finite element method to analyze the stability and deformation. The safety factor of foundation pit under the absence of retaining is much less than 1 through the limit-balance method, but through some retaining measures can guarantee its safety. According to the excavation of the foundation pit in special geological conditions, it takes pile-anchor retaining structure in upper and soil nailing in the lower part. Using the finite element to carry out dynamic simulation for the whole project, the results show that: this form of retaining can be very good to ensure the excavation of the foundation pit in the geological conditions, and it may be helpful for similar projects

Reinforcement Scheme and Numerical Simulation for Sequential Excavation of the Deep Foundation Pit

2012 ◽  
Vol 204-208 ◽  
pp. 359-365
Author(s):  
Rui Li Lu ◽  
Qing Hui Jiang
Keyword(s):  
Numerical Simulation ◽  
Middle Part ◽  
Deformation Monitoring ◽  
Soil Nailing ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Reinforcement Scheme ◽  
Deep Foundation Pit ◽  
Simulation Results ◽  
The Stability

The deep foundation pit engineering of Wanda Plaza in Yinchuan city is taken as a case study and the corresponding numerical model has been built. The deformation and stability of the foundation pit during sequential excavation has been analyzed by using of the FLAC3D software. The weak positions which may lose the stability are predicted by the results from the numerical simulation. A soil-nailing reinforcing scheme has been proposed to maintain the stability of the foundation pit. To analyze the support effects of the soil-nailing, the Cable structure elements have been adopted to simulate the interaction between soil and soil-nailing. The calculation results show that the maximum horizontal displacement occurs in the middle part of the pit wall and the minimum occurs in corner part of the pit wall. The soil nailing support significantly decreases the deformation of foundation pit by dispersing internal stress of soil. The reliability of the simulation results has been verified by the comparative analysis between the numerical simulation results and the deformation monitoring data of foundation pit. The proposed reinforcement scheme is not only helpful to ensure the safety of Wanda Plaza foundation pit，but also provides valuable experiences for the reinforcement of similar foundation pit engineering.

Analysis of Locking Value of Anchor Cable in Pile Anchor Supporting Structure

2013 ◽  
Vol 838-841 ◽  
pp. 203-208
Author(s):  
Jie Chen ◽  
Dong Wang ◽  
Chun Lei Feng
Keyword(s):  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Supporting Structure ◽  
Anchor Cable ◽  
The North ◽  
Relaxation Loss ◽  
Geological Conditions ◽  
Treatment Measures ◽  
The Stability

This paper analyses the problem of locking value of anchor cable of pile anchor supporting of a deep foundation pit in the north of Kunming city. There are many influencing factors of locking value of anchor cable such as relaxation loss of anchor cable materials, tensioning system, pre-stress loss caused by anchorage friction, geological conditions and so on. And the author put forward the corresponding treatment measures for achieving the stability of supporting structure.

Influence of C and Φ Values on Slope Supporting by Soil Nailing Wall in Thick Miscellaneous Fill Site

2013 ◽  
Vol 706-708 ◽  
pp. 504-507 ◽  
Author(s):  
Di Wu ◽  
Peng Wang ◽  
Guo Qiang Liu
Keyword(s):  
Internal Friction ◽  
Great Influence ◽  
Friction Angle ◽  
Soil Nailing ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Angle Of Internal Friction ◽  
The Stability ◽  
Slice Method

In recent years, soil nailing wall supporting technology is widely applied in the design of pit supporting. However, in the design of deep foundation pit supporting in miscellaneous fill site, the values of cohesion and angle of internal friction, that is c and φ, are too conservative to be chosen, so the security and economy cannot be obtained together. To study the influence of c and φ values on deep foundation pit supporting design in miscellaneous fill site, Lizheng-FSPw60 was the analysis software, and the circular sliding simple slice method was the theory. It is concluded that cohesion and internal friction angle of the soil have great influence on the stability of the soil nailing wall. Analysis and practice show that if c and φ values are reasonably chosen, the slope supported by soil nailing wall in thick miscellaneous fill site will be much safer, and the project will be less wasteful.

scholarly journals Combined Application of Optical Fibers and CRLD Bolts to Monitor Deformation of a Pit-in-Pit Foundation

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Chun Zhu ◽  
Kai Zhang ◽  
Huan Cai ◽  
Zhigang Tao ◽  
Bo An ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Slip Surface ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Combined Application ◽  
Wide Range ◽  
Constant Resistance ◽  
The Stability ◽  
The Many

“Pit-in-pit” foundations, where the overall pit is divided into inner and outer pits, present a wide range of engineering problems and yet have received little detailed study. Among the many factors that affect the stability of a deep foundation pit, loading and rainfall are the two most important. Therefore, in this study, physical model experiments are carried out in the laboratory based on a pit-in-pit foundation that is typical of engineering applications in China, simulating the deformation of the system under different loading and rainfall flow conditions. Optical fibers along with constant resistance and large deformation (CRLD) bolts are adopted to collectively monitor the stress and strain inside the pit-in-pit foundation, assisted by fiber Bragg grating (FBG) displacement meters. The results of the monitoring show that the position of the inner pit relative to the outer pit has a strong influence on the stability of the outer pit. The side on which the inner pit is closest to the outer pit wall is the most prone to instability and should thus be reinforced. Comparison and analysis of monitoring results obtained with optical fibers and CRLD bolts allow a potentially dangerous slip surface to be identified, indicating the value of using this type of collective monitoring in deep foundation pits.

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