Water Transport in Unsaturated Cracked Concrete under Pressure

Yuanzhu Zhang,Kuixin Xu,Liqiao Jin,Xinjiang Wei,Gang Wei,Siming Zhang

doi:10.1155/2019/4504892

Yuanzhu Zhang, Kuixin Xu + Show 4 more

Open Access

https://doi.org/10.1155/2019/4504892

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Abstract

In order to analyze the process of hydraulic water infiltrating cracked concrete of underwater tunnels, the equation of water transport in unsaturated cracked concrete under pressure was proposed according to the double-porosity medium model. Penetration tests on prefabricated cracked concrete blocks were conducted, and then the influence of hydraulic pressure, initial saturation, and crack width on water transport was studied. The results show that the larger the water pressure, the lower the initial saturation, and the wider the crack width, then the greater the penetration depth, which can be reasonably explained according to water motion theoretical models in this study. Moreover, the TOUGH2 software was used to simulate the change and distribution of saturation, driving potential, and water velocity of unsaturated cracked concrete, which further proved the experimental results and theoretical analysis. It reflects that both pressure potential and matric potential are the driving force of water transport in underwater cracked concrete, and the driving force will be converted with the change of concrete saturation. In addition, crack width is positively correlated with concrete permeability.

Highlights

For submerged constructions such as underwater tunnels which keep bearing high hydraulic pressure, it is a big challenge to prevent seepage in its service period
The equation of water transport in unsaturated cracked concrete under pressure was proposed based on the double-porosity medium model. en, the influence of hydraulic pressure, initial saturation, and crack width on water transport was studied through permeability tests. e TOUGH2 software was used to simulate the saturation, driving potential, and water flow velocity of unsaturated cracked concrete. e research is helpful to improve the durability design of the underwater concrete tunnel
It is found that the penetration depth increases with time in both directions and the penetration depth along the crack is essentially equal to the sum of crack length (30 mm) and the penetration depth in the vertical direction

Summary

Introduction

For submerged constructions such as underwater tunnels which keep bearing high hydraulic pressure, it is a big challenge to prevent seepage in its service period. Capillary absorption drives water transport in unsaturated concrete, which can be analyzed by Richards’ equation. Wang et al [11] put forward a mesoscale model for cracked concrete based on the theory of unsaturated flow and cubic law, and numerically analyzed the water content at the crack location. There are rare studies on combined transport of water in unsaturated cracked concrete under pressure and capillary suction up to now. Water transport in concrete of the underwater tunnel is permeability and capillary absorption. The equation of water transport in unsaturated cracked concrete under pressure was proposed based on the double-porosity medium model. En, the influence of hydraulic pressure, initial saturation, and crack width on water transport was studied through permeability tests. The equation of water transport in unsaturated cracked concrete under pressure was proposed based on the double-porosity medium model. en, the influence of hydraulic pressure, initial saturation, and crack width on water transport was studied through permeability tests. e TOUGH2 software was used to simulate the saturation, driving potential, and water flow velocity of unsaturated cracked concrete. e research is helpful to improve the durability design of the underwater concrete tunnel

Theoretical Basis

Experimental Research

Laboratory Tests

Results and Discussion

Numerical Analysis

Conclusion