Techno Press
Techno Press

Geomechanics and Engineering   Volume 14, Number 5, April10 2018, pages 467-477
DOI: http://dx.doi.org/10.12989/gae.2018.14.5.467
 
Hydraulic conductivity estimation by considering the existence of piles: A case study
Yao Yuan, Ye-Shuang Xu, Jack S. Shen and Bruce Zhi-Feng Wang

 
Abstract     [Full Text]
    Estimation of hydraulic parameters is a critical step during design of foundation dewatering works. When many piles are installed in an aquifer, estimation of the hydraulic conductivity should consider the blocking of groundwater seepage by the piles. Based on field observations during a dewatering project in Shanghai, hydraulic conductivities are back-calculated using a numerical model considering the actual position of each pile. However, it is difficult to apply the aforementioned model directly in field due to requirement to input each pile geometry into the model. To develop a simple numerical model and find the optimal hydraulic conductivity, three scenarios are examined, in which the soil mass containing the piles is considered to be a uniform porous media. In these three scenarios, different sub-regions with different hydraulic conductivities, based on either automatic inverted calculation, or on effective medium theory (EMT), are established. The results indicate that the error, in the case which determines the hydraulic conductivity based on EMT, is less than that determined in the automatic inversion case. With the application of EMT, only the hydraulic conductivity of the soil outside the pit should be inverted. The soil inside the pit with its piles is divided into sub-regions with different hydraulic conductivities, and the hydraulic conductivity is calculated according to the volume ratio of the piles. Thus, the use of EMT in numerical modelling makes it easier to consider the effect of piles installed in an aquifer.
 
Key Words
    piles; aquifer; dewatering; hydraulic conductivity; numerical model; EMT
 
Address
Yao Yuan and Ye-Shuang Xu: 1.) State Key Laboratory of Ocean Engineering and Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
2.) Key Laboratory of Land Subsidence Monitoring and Prevention, Ministry of Land and Resources, and Shanghai Engineering Research Center of Land Subsidence, Shanghai 200072, China

Jack S. Shen: 1.) State Key Laboratory of Ocean Engineering and Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Department of Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
2.) Department of Civil and Construction Engineering, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia

Bruce Zhi-Feng Wang: Department of Geotechnical and Tunnelling Engineering, School of Highway, Chang
 

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