Influence of High Water Pressure on Static and Dynamic Compressive Strength of Concrete

In this paper, an experimental study was conducted on the influence of water pressure on concrete strength. Specimens were put in a self-designed device, applying 0–4 MPa water pressure on concrete, and then taken out for both static and dynamic compressive tests. Results showed that high water pressure caused inevitable damage to concrete, leading to 13.4% reduction in strength under 4 MPa water pressure. Specimens with lower strength grade were damaged more severely while under the same water pressure. Also, as water pressure increased, the moisture content of concrete grew linearly, and the trend for specimens with higher compressive strength was slower. A correlation was established between the water content increment and the reduction rate of strength. Moreover, the dynamic compressive strength decreased as water pressure increased but still higher than the static strength, illustrating an apparent strain rate effect. Meanwhile, water pressure and moisture content increment barely had any influence upon DIF within the testing conditions. Furthermore, equations for calculating both static and dynamic reduction rates of strength were built, based either on water pressure or on moisture content increment caused by that. Equations for strength prediction were also provided.

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Investigating the Effect of Repeated High Water Pressure on the Compressive and Bond Strength of Concrete with/without Steel Bar

Materials ◽

10.3390/ma14030527 ◽

2021 ◽

Vol 14 (3) ◽

pp. 527

Author(s):

Ahmad Aki Muhaimin ◽

Mohamed Adel ◽

Kohei Nagai

Keyword(s):

Compressive Strength ◽

Bond Strength ◽

Water Pressure ◽

High Water ◽

Pullout Capacity ◽

Internal Damage ◽

Residual Compressive Strength ◽

Steel Bar ◽

Concrete Cylinders ◽

High Water Pressure

The application of reinforced concrete for permanent and temporary deep ocean structures has recently become more prevalent; however, the static and dynamic effects of high water pressure on concrete remain unexplored. This paper investigates the influence of high water pressure (60 MPa) on four series of concrete cylinders with and without an embedded steel bar under sustained and cyclic loading conditions. The residual compressive strength, bond strength, and associated evolution of surface and internal damage are evaluated after exposing concrete cylinders to a water pressure of 60 MPa. The first series is exposed to sustained water pressure for 7 and 60 days, while the other series is tested under repeated water pressure for 10, 20, 30, 60, and 150 cycles. The results reveal that residual compressive strength falls immediately by 16% within 7 days of sustained high water pressure, but the strength then remains stable up to 60 days. Under repeated high water pressure, residual compressive strength gradually reduces by up to 40% until 60 cycles, after which it remains reasonably stable until 150 cycles as crack propagation is arrested at a certain depth within the concrete cylinders. The bond strength between the steel bar and matrix is observed to decrease considerably under repeated cycles of 60 MPa water pressure up to 26%. The damage gradually propagates at the matrix/steel bar interface under the repeated water pressure, resulting in a reduction in residual pullout capacity.

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Study on Mechanical Characteristics of Segmental Joints of a Large-Diameter Shield Tunnel under Ultrahigh Water Pressure

Sensors ◽

10.3390/s21248392 ◽

2021 ◽

Vol 21 (24) ◽

pp. 8392

Author(s):

Lei Kou ◽

Zhihui Xiong ◽

Hao Cui ◽

Jinjie Zhao

Keyword(s):

Numerical Simulation ◽

Theoretical Calculation ◽

Water Pressure ◽

Concrete Strength ◽

Large Diameter ◽

Simulation Method ◽

High Water ◽

Calculation Model ◽

Bending Stiffness ◽

High Water Pressure

At present, there is no clear design standard for segmental joints of large-diameter shield tunnels under high water pressure. In this paper, a theoretical calculation model for the bending stiffness of segmental joints under high water pressure is proposed. The numerical simulation method is used to investigate the failure and crack formation processes of single-layer and double-layer lining segments under large axial forces. The effects of axial force, bolt strength, and concrete strength on the bending stiffness of joints are then studied using a theoretical calculation model of segmental joints. The results show that under extremely high water pressure, the influence of double lining on joint stiffness is limited. It is more rational and safe to compute the bending stiffness of segmental joints using this theoretical model rather than the numerical simulation method. The parameter analysis reveals that increasing the bolt strength has a minor impact on bending stiffness and deformation, whereas increasing the concrete strength has the opposite effect. The influence of ultimate bearing capacity and deformation decreases non-linearly as the axial force increases.

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Structural modifications of lanthanum silicate oxyapatite exposed to high water pressure

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2016.12.034 ◽

2017 ◽

Vol 37 (5) ◽

pp. 2149-2158 ◽

Cited By ~ 6

Author(s):

Aénor Pons ◽

Emilie Béchade ◽

Jenny Jouin ◽

Maggy Colas ◽

Pierre-Marie Geffroy ◽

...

Keyword(s):

Water Pressure ◽

High Water ◽

Structural Modifications ◽

Lanthanum Silicate ◽

High Water Pressure

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Model Test Research on the Mechanical Characteristics of Tunnel Lining Structures under Local High Water Pressure in Concealed Karsts

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/861/2/022010 ◽

2021 ◽

Vol 861 (2) ◽

pp. 022010

Author(s):

Meihai Jin ◽

Xinrong Liu ◽

Zuliang Zhong

Keyword(s):

Model Test ◽

Mechanical Characteristics ◽

Water Pressure ◽

High Water ◽

Tunnel Lining ◽

High Water Pressure

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Analysis on Water Inrush Process of Tunnel with Large Buried Depth and High Water Pressure

Processes ◽

10.3390/pr7030134 ◽

2019 ◽

Vol 7 (3) ◽

pp. 134 ◽

Cited By ~ 6

Author(s):

Weimin Yang ◽

Zhongdong Fang ◽

Hao Wang ◽

Liping Li ◽

Shaoshuai Shi ◽

...

Keyword(s):

High Pressure ◽

Model Test ◽

Water Pressure ◽

Water Inrush ◽

High Water ◽

Surrounding Rock ◽

Karst Cave ◽

Tunnel Excavation ◽

Pressure Water ◽

High Water Pressure

In order to explore the catastrophic evolution process for karst cave water inrush in large buried depth and high water pressure tunnels, a model test system was developed, and a similar fluid–solid coupled material was found. A model of the catastrophic evolution of water inrush was developed based on the Xiema Tunnel, and the experimental section was simulated using the finite element method. By analyzing the interaction between groundwater and the surrounding rocks during tunnel excavation, the law of occurrence of water inrush disaster was summarized. The water inrush process of a karst cave containing high-pressure water was divided into three stages: the production of a water flowing fracture, the expansion of the water flowing fracture, and the connection of the water flowing fracture. The main cause of water inrush in karst caves is the penetration and weakening of high-pressure water on the surrounding rock. This effect is becoming more and more obvious as tunnel excavation progresses. The numerical simulation results showed that the outburst prevention thickness of the surrounding rock is 4.5 m, and that of the model test result is 5 m. Thus, the results of the two methods are relatively close to each other. This work is important for studying the impact of groundwater on underground engineering, and it is of great significance to avoid water inrush in tunnels.

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