scholarly journals Effect of spalling thickness on transverse axial bearing capacity of pile foundation under different corrosion depths

2020 ◽  
Vol 198 ◽  
pp. 02019
Author(s):  
Zhongju Feng ◽  
Yunhui Guan ◽  
Suizhu Guo ◽  
Zhouyi Huang ◽  
Jingbin He ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Bearing Capacity ◽  
Pile Foundation ◽  
Zero Point ◽  
Highway Bridge ◽  
Displacement Curve ◽  
Corrosion Depth ◽  
Marsh Area ◽  
Bridge Pile Foundation ◽  
Salt Marsh Area

The transverse and axial bearing characteristics of bridge pile foundation in salt marsh area are studied by numerical simulation. This paper mainly analyses the change of transverse and axial bearing characteristics of pile foundation caused by the change of spalling thickness of bridge foundation. The results show that the transverse and axial bearing capacity and displacement of pile foundation will be affected by the change of concrete spalling thickness under the condition of pile corrosion. When the peeling thickness is above 9.0cm, the transverse and axial bearing characteristics of pile foundation are obviously different with the change of corrosion depth of pile body. When the peeling thickness increases and the corrosion depth of the pile body is different, the negative displacement below the zero point of the first displacement of the pile body is continuously reduced, and the displacement curve above the first displacement zero point in the direction of the pile body begins to shift. When the peeling thickness reaches 15.0cm, the pile top displacement increases to 3.75mm. The research results are of great significance to the establishment of safety evaluation system of highway bridge pile foundation in alpine salt marsh area, and provide a basis for the structural design of highway bridge pile foundation in alpine salt marsh area.

scholarly journals Experimental and Application Study on Underpinning Engineering of Bridge Pile Foundation

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Lei Yan ◽  
Gang Wang ◽  
Min Chen ◽  
Kefeng Yue ◽  
Qingning Li
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Shear Capacity ◽  
Application Study ◽  
Calculation Results ◽  
Shear Bearing Capacity ◽  
Similarity Ratio ◽  
Loading Tests ◽  
New Formula ◽  
Bridge Pile Foundation

In order to study the theory and application of the pile foundation underpinning technology, 3 local node models of underpinning structures with a similarity ratio of 1/1 were made and the progressive repeated static loading tests were conducted. The shear and antislip properties of the joint are studied, and the improved formula for calculating the shear capacity is proposed. The results show that a planting bar plays a major role in shear resistance, and the hoop rate can improve the shear capacity of the interface. The new formula for calculating the shear-bearing capacity is proposed, and the calculation results of the formula of shear-bearing capacity are in good agreement with the experiment results. It is completely feasible to use this formula to calculate the shear-bearing capacity of the pile foundation underpinning structure. During the test, the bearing capacity of the model is good, which proves the reliability of the underpinning technology is good, and it can provide experimental and theoretical basis for the underpinning of similar projects.

scholarly journals Environmental factors affecting larval fish community in the salt marsh area of Guadiana estuary (Algarve, Portugal)

2015 ◽  
Vol 79 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Renata Gonçalves ◽  
Ana Dulce Correia ◽  
Natasa Atanasova ◽  
Maria Alexandra Teodósio ◽  
Radhouan Ben-Hamadou ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Environmental Factors ◽  
Fish Community ◽  
Larval Fish ◽  
Factors Affecting ◽  
Marsh Area ◽  
Salt Marsh Area ◽  
Guadiana Estuary

scholarly journals The effect of macrofauna, meiofauna and microfauna on the degradation of Spartina maritima detritus from a salt marsh area

1999 ◽  
Vol 20 (4) ◽  
pp. 249-258 ◽  
Author(s):  
Ana Isabel Lillebø ◽  
Mogens R. Flindt ◽  
Miguel Ângelo Pardal ◽  
João Carlos Marques
Keyword(s):  
Salt Marsh ◽  
Spartina Maritima ◽  
Marsh Area ◽  
Salt Marsh Area

scholarly journals Numerical analysis of the forming process of the bearing capacity of the auxiliary pile foundation in Permafrost area

2020 ◽  
Vol 198 ◽  
pp. 02002
Author(s):  
Sun Jianzhong ◽  
Guo Chunxiang ◽  
Wang Xu ◽  
Zhang Weijia
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Initial Conditions ◽  
Interface Temperature ◽  
Engineering Practice ◽  
Confined Water ◽  
Foundation Soil ◽  
Soil System ◽  
Heat Transfer Theory ◽  
Bridge Pile Foundation

Bore Cast-in-place Piles broke the original water and heat balance state of the stratum in the bridge construction of Qinghai Tibet railway. The settlement of a bridge pile foundation was relatively large after more than ten years of operation. It was found that there is confined water in the foundation soil after investigation. Engineers planned to add auxiliary piles at the original pile side to reduce the settlement of the pile foundation.This paper studied the temperature change, bearing capacity formation rule and long-term bearing capacity change trend of the new pile-soil system after adding auxiliary piles on the original foundation, which provides certain theoretical basis and reference basis for engineering practice. A three-dimensional model of a bridge pile foundation was established by numerical method. Considering the influence of atmospheric temperature, hydrogeological conditions, concrete temperature into the mold, and the temperature of underground confined water, based on the heat transfer theory, the boundary conditions and initial conditions are given. The influence of the change of ground temperature field and the change of pile-soil interface temperature on the bearing capacity of the foundation was studied after the auxiliary pile was poured. The analysis shows that the measure to increase the bearing capacity by adding auxiliary piles is a double-edged sword. On the one hand, the auxiliary piles themselves constitute the bearing capacity together with the original pile foundation after thawing, on the other hand, the auxiliary piles are constructed by the method of pouring concrete in the field. The hydration heat of concrete makes the temperature of the original foundation soil rise, and reduces its bearing capacity. The whole bearing capacity will not be increased at the initial stage, but also will be temporarily reduced, and the whole bearing capacity will be formed after the frozen soil is frozen back in the later stage.

scholarly journals The vegetation of a relict salt marsh area in the Pisan coast in the context of brackish wetlands of Tuscany

2021 ◽  
Vol 58 (1) ◽  
pp. 41-53
Author(s):  
Andrea Bertacchi ◽  
Tiziana Lombardi ◽  
Angela Saggese ◽  
Valerio Lazzeri
Keyword(s):  
Salt Marsh ◽  
Plant Communities ◽  
Agricultural Activities ◽  
Marsh Area ◽  
Vegetation Surveys ◽  
Salt Marsh Area ◽  
Neighboring Area ◽  
Phytosociological Study

The paper presents the results of phytosociological surveys carried out in Galanchio-Cornacchiaia, a salt marsh area on the Pisan coast (northern Tuscany), which survived the agricultural reclamation. The vegetation surveys confirm the brackish features of the site, while highlighting three substantially different subareas in terms of prevailing vegetation. The phytosociological study allowed the identification of 11 marsh phytocoenoses attributable to 12 associations (Crypsidetum aculeatae; Parapholidetum filiformis; Suaedo maritimae-Salicornietum patulae; Suaedetum maritimae; Puccinellio festuciformis-Halimionetum portulacoidis; Puccinellio festuciformis-Sarcocornietum perennis; Elytrigio elongatae-Inuletum crithmoidis; Limonio narbonensis-Juncetum gerardi; Puccinellio festuciformis-Aeluropetum litoralis, Junco maritimi-Spartinetum junceae; Juncetum maritimi-acuti; Phragmitetum australis). These plant communities are referable to 3 brackish habitats and related subtypes, reported in 92/43 ECC Directive habitats. This biotope, although part of the neighboring area of the Regional Park of Migliarino San Rossore Massaciuccoli, is currently in an extremely precarious balance and threatened by the surrounding agricultural activities. The knowledge of its naturalistic peculiarities and remarkable biodiversity, can contribute to its increased protection and conservation. This study add new data to the knowledge of the brackish vegetation of Tuscany.

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