Effect of Foundation Pit With Different Support and Excavation Methods on Adjacent Buried Hydrogen Pipe

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Jie Zhang ◽  
Rui Xie
Keyword(s):  
High Stress ◽  
Horizontal Displacement ◽  
Lower Surface ◽  
Middle Part ◽  
Foundation Pit ◽  
Common Support ◽  
Slope Excavation ◽  
Lateral Reinforcement ◽  
Bolt Support ◽  
Excavation Methods

Abstract Support and excavation methods have a great effect on the supporting role of the foundation pit. To investigate the effect of foundation pit with different support and excavation methods on adjacent buried hydrogen pipe, a pipe–soil coupling model was established. Deformation, strain, and stress of the pipe near the foundation pit with different support and excavation methods were analyzed. The results show that stress concentration appears on the upper and lower surfaces of the middle part of the pipe after the foundation pit excavation. The high stress areas on the upper and lower surfaces are distributed symmetrically about the pipe center. Upper surface of the pipe's middle section is pressed and the lower surface is pulled, but the strain distribution of the pipe at the pit edge is opposite. Vertical displacement of the pipe is bigger than its horizontal displacement. The underground continuous wall as the most common support structure can effectively reduce the pipe deformation. Supporting methods have different effects on buried pipe's mechanical behavior. Lateral reinforcement, inner support, and bolt support can effectively reduce the pipe deformation, but the mitigating effect of lateral reinforcement is less than inner support and bolt support. The pipe is also affected by time and space of the foundation pit excavation. The slope excavation can greatly reduce the pipe deformation, but the effects of island excavation and basin excavation are not obvious. Those results can provide references for pipe safety assessment and protection.

scholarly journals Numerical Investigation of a Foundation Pit Supported by a Composite Soil Nailing Structure

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 252 ◽  
Author(s):  
Wei Han ◽  
Genxiao Li ◽  
Zhaohui Sun ◽  
Hengjie Luan ◽  
Chuanzheng Liu ◽  
...  
Keyword(s):  
Side Wall ◽  
Horizontal Displacement ◽  
Middle Part ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Soil Nails ◽  
Factors Affecting ◽  
Composite Soil Nailing ◽  
Soil Foundation ◽  
The Stability

In special geology conditions such as silt-soil, foundation pits are prone to instability and severe deformation. In this paper, a composite soil nailing structure was studied and its effect on a silt-soil symmetrical foundation pit investigated. The factors affecting the stability of the pit as well as its deformation characteristics were also explored. The results show that excavation depth of the foundation pit has a significant impact on its stability. The soil outside the foundation pit is in the form of a parabola, and the uplift of the soil mainly occurs at the bottom. The horizontal displacement of soil on the side wall of the foundation pit presents a “bulk belly” form. In addition, the axial force of soil nails is larger in the middle part, and smaller at both ends in the shape of a spindle. Moreover, the horizontal displacement is positively correlated with the inclination and spacing of the soil nails, but negatively correlated with the diameter and depth of the mixing pile inlay. Furthermore, the inclination and spacing of the soil nails, the diameter, and embedded depth of the mixing pile have their own critical values for stability of the foundation pit. Specifically, in this paper, with respect to soil nails, inclination should be below 30° and prestress value should not exceed 20 kN. With respect to the mixing pile, the diameter should be less than 1.5 m; when the embedded depth of the mixing pile exceeds the critical depth, the limiting effect of the mixing pile on horizontal displacement is not significant. This research provides important takeaways for the design of a composite soil nailing structure for symmetrical foundation pits.

Finite Element Analysis and Investigation of Double-Row Piles Supporting Structure

2013 ◽  
Vol 838-841 ◽  
pp. 779-785
Author(s):  
Liang Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Shear Stress ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
Element Analysis ◽  
Supporting Structure

The double-row piles supporting structure is a new type of supporting and protecting for deep foundation excavation. It is widely used to in design of deep foundation pit. Now how to simply and effectively design the structure of double-row piles is in a research and discuss stage. Using the Midas GTS finite element method, the displacement and stress distribution of double-row piles in the different stages of excavation are obtained, and the horizontal displacement and stress distribution of double-row piles in the different stages of excavation are calculated. The results of Midas GTS finite element analysis as follows: (1) after the excavation of foundation pit, the horizontal displacement of pile-top is maximum. The horizontal displacement decreases gradually with depth increases. And the displacement of front row piles is larger than that of back row piles; (2) the maximum shear stress is at the distance 5m to the foundation basement. The higher bending moment at the pile-top and the distance 10m to the foundation basement are consistent with the actual monitoring date. (3) the results of finite element analysis is close to the Richard software and actual monitoring data. It is show that using the finite element analysis to analyze the double-row piles supporting structure with is veritable and credible.

Monitoring and Analysis for the Deformation of SMW Retaining Structures in Subway Station

2014 ◽  
Vol 580-583 ◽  
pp. 1249-1253
Author(s):  
Jiang Tao Xia ◽  
Shao Fei Zhang ◽  
Hua Rong Shen ◽  
Ze Jun Liu ◽  
Shi Qing Huang
Keyword(s):  
Early Stage ◽  
Horizontal Displacement ◽  
Ground Subsidence ◽  
Subway Station ◽  
Deep Soil ◽  
Foundation Pit ◽  
Retaining Structures ◽  
Soil Mixing ◽  
Wall Structures ◽  
Soil Excavation

The monitoring is carried out for deformation of the soil-mixing-wall structures used in Baijihu subway station. The horizontal displacement of deep soil is obtained, as well as the ground subsidence around the edges of the foundation pit. Their variation rules under the influence of some factors, such as soil excavation and support settings etc, is analyzed. The results show that during the process of SMW construction, it is necessary to monitor the horizontal displacement of deep soil and the ground subsidence around the edges of the foundation pit, especially during the early stage of excavation.

Analysis of Construction Monitoring of Jinzhou Underground Mall Excavation

2013 ◽  
Vol 848 ◽  
pp. 74-77
Author(s):  
Jin Kui Li ◽  
Yue Bo Fan ◽  
Yi Bing Wang
Keyword(s):  
Environmental Conditions ◽  
Horizontal Displacement ◽  
Ground Settlement ◽  
Foundation Pit ◽  
Construction Monitoring ◽  
Construction Period ◽  
Surrounding Environment ◽  
Information Construction ◽  
Real Time Information ◽  
Time Information

Cause the deformation of soil around the foundation pit excavation, have a great impact on the surrounding environment. At the same time, the excavation is limited by surrounding environmental conditions. Relying on the Jinzhou underground mall excavation monitoring project, after monitoring the ground settlement and horizontal displacement of pile top and measurement during the construction period, we realize the real-time information construction ,safe and smooth construction in the process of construction. And we conclude some useful conclusions, which can be a reference for similar engineering and reference.

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.

Study on Composite Soil Nailing Wall in Soft Soil Area of Complex Condition with Emphasis on Analysis by Finite Element Analysis

2012 ◽  
Vol 174-177 ◽  
pp. 2020-2023 ◽  
Author(s):  
Bing Wang
Keyword(s):  
Finite Element ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Circular Area ◽  
Foundation Pit ◽  
Soil Nails ◽  
Deep Foundation Pit ◽  
Soft Soil Area ◽  
Soil Area

Based on a typical projects, the horizontal displacement in depth, horizontal displacement and vertical subsidence of pile top, and settlements of surrounding buildings are monitored with the process on digging of deep foundation pit. The study on digging process of foundation pit is analyzed by using finite element software. Using mapped meshing method, from mixing the pile near the semi-circular area (radius = 50m), the meshing appropriate encryption in order to improve the accuracy of the external semi-circular area (radius = 65m) mesh is less appropriate sparse.Layer by layer to kill the layers of the soil unit and activate the soil nails (spring element), the simulated excavation and synchronization of soil nails construction.Verify the arc form of failure surface in side of deep foundation pit in soft soil area. Which is valuable for reference to similar structure engineering of foundation pit.

Deep Foundation Pit Monitoring Based on CX-3C Inclinometer

2014 ◽  
Vol 484-485 ◽  
pp. 404-407 ◽  
Author(s):  
Qing Guo Ren ◽  
Guang Zhang ◽  
Xiao Guang Yue ◽  
Wen Cheng Liao
Keyword(s):  
Vertical Profile ◽  
Retaining Wall ◽  
Horizontal Displacement ◽  
Displacement Monitoring ◽  
Deep Soil ◽  
Security Risks ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Main Factors

Deep soil horizontal displacement monitoring can measure the retaining wall board, row piles deformed shape, reflect the foundation on the vertical profile of horizontal displacement with depth changes in the law, predict foundation stability and security risks. Combined with Wuhan WANGJiaDun Pit Engineering, this article introduce CX-3C inclinometer work principle, put forward the calculated optimization measures of inclinometer, and analysis the main factors which should be considered to arrange the measuring points.

Prestressed Anchor Bolt Impact on the Deformation of Composite Soil Nailing

2013 ◽  
Vol 353-356 ◽  
pp. 11-15
Author(s):  
Deng Qun Wang ◽  
Yan Peng Zhu
Keyword(s):  
Axial Force ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Obvious Effect ◽  
Anchor Bolt ◽  
Soil Nail ◽  
Finite Element Software ◽  
The Impact

Finite element software was employed to establish a model to simulate the compound soil nailing. The model simulates the process of constructing prestressed compound soil nailing. Compared the condition prestressed with no prestress, analyzed the Impact of prestress anchor on the deformation in the process of construction and the effect on axial force of soil nail. Applying prestress is able to control the horizontal displacement obviously, but has not obvious effect on vertical displacement, especially place the anchor bolt at the lower part of the slope. In the process of construction, prestress has an advance effect on the deformation of foundation pit and the axial force of soil nails near the anchor bolt.

Construction Technology of one Unsymmetrical Loaded Deep Foundation Pit Adjacent to Expressway Subgrade

2014 ◽  
Vol 919-921 ◽  
pp. 1411-1415
Author(s):  
Bo Liu ◽  
Pei Sheng Xi
Keyword(s):  
Horizontal Displacement ◽  
Urban Rail Transit ◽  
Construction Technology ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Urban Rail ◽  
Relative Value ◽  
Lower Load ◽  
Loaded State

One deep foundation pit in Hefei urban rail transit project is adjacent to the existed expressway subgrade, it's in the unsymmetrical loaded state. The control of foundation pit deformation and the safety of subgrade must be strictly ensured. Based on it, the design scheme of supporting system, the construction processes of earth excavation, top beam, concrete support and steel support was introduced. The horizontal displacement of fender piles and the settlement of subgrade was monitored. The field monitoring results indicate, there exists a great difference between the retaining structure deformation under the action of unsymmetrical load and the deformation under the action of symmetrical load, the horizontal displacement of fender piles on the side of subgrade is bigger than the other side, the upper pile appears to be a "drift" towards the lower-load side; although the absolute value of horizontal displacement of fender piles and settlement of subgrade seems to be a big number, the relative value is small compared to the whole length of fender pile and expressway, meeting relevant standard requirements. The deep foundation pit and expressway kept safe and stable in the all periods of construction, no one accident was occurred during that time. Thus, it can be seen that this construction technology is effective in controlling the deformation during excavation, which can provide a reference for similar projects in design and construction in the future.

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