The Efficiency of Horizontal Drainage Layers for Accelerating Consolidation of Clay Embankments

Géotechnique ◽  
1968 ◽  
Vol 18 (3) ◽  
pp. 327-335 ◽  
Author(s):  
R. E. Gibson ◽  
Gilliane C. Shefford
Keyword(s):  
Drainage Layers ◽  
Horizontal Drainage

Effects of Horizontal Drainage Layer for Seepage Control on Mitigation of Liquefaction of Levee Body

2012 ◽  
Vol 7 (6) ◽  
pp. 733-738
Author(s):  
Akihiro Takahashi ◽  
Keyword(s):  
Numerical Analysis ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Liquefaction ◽  
Drainage Layer ◽  
Major Function ◽  
Seepage Control ◽  
Drainage Layers ◽  
Horizontal Drainage ◽  
Eventual Collapse

The 2011 Tohoku Pacific Earthquake of March 11 caused extensive damage due to soil liquefaction, triggering major deformations in and eventual collapse of levees. At the same time, the effectiveness of measures to counter the liquefaction of levee foundations was confirmed in many places. In addition, measures for seepage control, such as cut-offs with steel sheet piles for foundation under-seepage and horizontal drainage layers for seepage through embankments, were effective in mitigating large liquefaction-induced deformation of levees in some places. This paper focuses on the effects of the horizontal drainage layer for seepage control on the mitigation of the liquefaction of levees and reports the results of numerical analysis on a levee that survived the earthquake. Analysis results reveal that effects of the drainage layer on the mitigation of levee deformation were unexpectedly low, while a marked difference was seen at the site. Accepting the limitations of numerical analysis, it can be concluded that (1) the major function of the horizontal drainage layer on liquefaction-induced levee damage was to lower the water table in the levee and (2) drainage did not help much in the dissipation of excess pore water pressure in the levee during an earthquake.

scholarly journals The Effects of Grout Curtain Parameters on Uplift and Piping Phenomenon; Case Study: Sattarkhan Dam

Hydrology ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 71
Author(s):  
Kambiz Meshkabadi ◽  
Yousef Zandi
Keyword(s):  
Numerical Models ◽  
Grout Curtain ◽  
Hydraulic Structures ◽  
Uplift Pressure ◽  
The Core ◽  
Horizontal Drainage ◽  
Potential Risks ◽  
Dam Core ◽  
Water Seal

Design of earth dams and their issues during and after construction is very important for residents downstream of the dam because of the potential risks and possible breakdowns. In the design of dams, various forces influence the dam body, including uplift pressure and piping phenomenon which should be considered in order to ensure the safety of the dam. Among the measures taken to prevent the washing away phenomenon, the reduction of the output gradient, and the leakage discharge from beneath the hydraulic structures, construction of the grout curtain and installation of the drainage are applicable. Therefore, in order to investigate the effect of various parameters such as the gradient angle of the grout curtain, length, and distance and the number of grout curtains, as well as the length of the drainage on the pressure and output gradient of the numerical models, were considered in current study. For this purpose, the SEEP/W software was used for modeling on Sattarkhan Dam as a case study. The results of the analysis showed that the use of the Qa’im grout curtain at the upstream of the dam has the highest resistance against the pressure and piping phenomenon. The results also showed that increase in the length of the curtain of the water seal increases safety against uplift and piping phenomenon. The use of further spacing between the two grout curtains under the core of the dam led to increase in overall pressure or reduction in safety against uplift pressure. Increase in the length of the horizontal drainage reduced the effects of uplift pressure and output gradient. Results show that period of 70 to 110 degree is appropriate for curtain angle and setting curtain in upstream of dam core with angle of 70 to 80 degree is optimum and economic. A length of 30 m is optimum for curtain. The number of 2 curtains is also optimum. Studying various scenarios of distance of 2 curtains in dam core indicates that distance of 6 m is optimum and also length of 18 m for horizontal drainage is optimum.

Research on Influencing Factors of Drainage Performance in Engineering

2012 ◽  
Vol 212-213 ◽  
pp. 671-678
Author(s):  
Xu Shu Sun ◽  
Jian Lin Li ◽  
Xiao Liang Xu ◽  
Jian Rrong Li ◽  
Fei Liu
Keyword(s):  
Influencing Factors ◽  
Small Angle ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Soil Mass ◽  
Vertical Permeability ◽  
Horizontal Drainage ◽  
Drainage Hole ◽  
Better Than

In order to control the seepage and eliminate the adverse effects, influencing factors of drainage in engineering are discussed in this paper. The drainage holes are simulated by rod element to study the influence of drainage performance on angle and length. Compared the drainage performance of drainage galleries in different location, the optimal assembly is obtained. Meanwhile, drainage performance is analyzed by different permeability coefficient and anisotropy of rock and soil mass. The results show that: (1) Drainage flow of small angle and short drainage hole is close to big angle and long one, the small angle flows more than the big angle when increasing the same length. (2) Shallow drainage galleries can significantly drop the free surface and the deep one can greatly decrease the pore water pressure. Drainage galleries built at the upstream side and bottom, as the optimum assembly, can enormously change the seepage field. (3) For anisotropy materials, the horizontal drainage performance is better than vertical when Ky/Kx decreases. On the contrary, vertical is superior to the horizontal. Increasing vertical permeability coefficient is benefit to drainage.

Using a Rowe Cell to Establish Horizontal Drainage Properties of Soft Soils

2014 ◽  
Author(s):  
Clifton B. Farnsworth ◽  
Steven F. Bartlett ◽  
Evert C. Lawton
Keyword(s):  
Soft Soils ◽  
Horizontal Drainage ◽  
Rowe Cell
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