Response Analysis of Excavation of Deep Foundation Pit in Metro Station of Soft Soil

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.2338 ◽

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.174-177.2020 ◽

2012 ◽

Vol 174-177 ◽

pp. 2020-2023 ◽

Cited By ~ 1

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.

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Analysis of the stability monitoring and deformation characteristics of deep foundation pit in soft soil

2011 International Conference on Remote Sensing, Environment and Transportation Engineering ◽

10.1109/rsete.2011.5965651 ◽

2011 ◽

Author(s):

Chengjun Bai ◽

Hailing Zhang

Keyword(s):

Soft Soil ◽

Deformation Characteristics ◽

Deep Foundation ◽

Foundation Pit ◽

Deep Foundation Pit ◽

Stability Monitoring ◽

The Stability

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Deformation Law of the Diaphragm Wall during Deep Foundation Pit Construction on Lake and Sea Soft Soil in the Yangtze River Delta

Advances in Civil Engineering ◽

10.1155/2021/6682921 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Yuan Mei ◽

Dongbo Zhou ◽

Xueyan Wang ◽

Liangjie Zhao ◽

Jinxin Shen ◽

...

Keyword(s):

Soft Soil ◽

Yangtze River Delta ◽

Diaphragm Wall ◽

Lateral Deformation ◽

Deep Foundation ◽

Foundation Pit ◽

Deep Foundation Pit ◽

Deformation Law ◽

Wall Deformation ◽

Subway Stations

So far, there have been a large number of diaphragm walls in the Yangtze River Delta as engineering examples of deep foundation pit maintenance structures in subway stations, but there is a lack of systematic research and summary on the deformation characteristics of ground connecting walls. This study aimed to clarify the deformation law of the diaphragm wall during the excavation of a deep foundation pit in a soft soil region. Based on the monitoring data of the diaphragm wall of the deep foundation pit of the Hangzhou metro station, the monitoring data of the deep foundation pits of 15 subway stations in Shanghai and Ningbo cities around Hangzhou were considered. Grouping and classification methods were used to analyze the similarities and differences in the deformation characteristics of the diaphragm wall in the three regions. The results indicate the following: the maximum lateral deformation of the diaphragm wall in Hangzhou increases linearly with the relative depth of the maximum lateral deformation. The maximum lateral deformation of the foundation pit in Hangzhou is 0.072% H∼0.459% H, with a mean of 0.173% H. The wall deformation in Hangzhou varies significantly with the depth of the foundation pit, but the influence of the depth of the foundation pit on the wall deformation is considerably less than that in Shanghai and Ningbo. The corresponding position of the maximum lateral deformation in the excavation depth increases linearly with the excavation depth of the foundation pit, and the corresponding position of the lateral deformation of the diaphragm wall in Shanghai is more affected by the excavation depth of the foundation pit. The lateral deformation of the diaphragm wall increases rapidly in the range of 0 H–0.5 H, and the maximum lateral deformation occurs at 0.5 H–1.1 H.

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Numerical Simulation of Soil Displacement and Settlement in Deep Foundation Pit Excavations Near Water

Geofluids ◽

10.1155/2021/5559009 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Zhongjing Hu ◽

Qingbiao Wang ◽

Shuo Yang ◽

Zhenyue Shi ◽

Bo Liu ◽

...

Keyword(s):

Numerical Simulation ◽

Large Scale ◽

Yellow River ◽

Soft Soil ◽

Ground Surface ◽

Horizontal Displacement ◽

Simulation Method ◽

Deep Foundation ◽

Foundation Pit ◽

Deep Foundation Pit

Advancing urbanization in China requires large-scale high-rise construction and underground transportation projects. Consequently, there is an increasing number of deep foundation pits adjacent to water bodies, and accidents occur frequently. This study uses a numerical simulation method to study the stability of the deep foundation pit near water based on the Biot three-dimensional seepage-stress coupling model, with the open-cut section on the south bank of the Jinan Yellow River Tunnel Project as the engineering field test. This indicates the following: (1) the maximum horizontal displacement of the diaphragm wall occurred in the fifth excavation stage, and a horizontal brace effectively controlled the inward horizontal displacement of the foundation pit; (2) considering the effect of seepage in the soft soil foundation, the maximum vertical displacement of the ground surface at each excavation stage occurred adjacent to the underground continuous wall. As the depth of the foundation pit increased, the vertical surface settlement decreases gradually in the direction away from the excavation face; (3) considering the seepage conditions, within each interval of excavation of the foundation pit, the horizontal displacement of the continuous underground wall and ground settlement declined; and (4) the numerical simulation and field monitoring data were in good agreement. Under the conditions of accurate model simplification and parameter selection, numerical simulations can adequately forecast conditions of the actual project.

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