Parameters affecting the thickness of bentonite cake in cutoff wall construction: case study and physical modeling

2005 ◽  
Vol 42 (2) ◽  
pp. 646-654 ◽  
Author(s):  
Abbas Soroush ◽  
Mohammad Soroush
Keyword(s):  
Physical Model ◽  
Physical Model Test ◽  
Test Results ◽  
Cutoff Wall ◽  
Bentonite Slurry ◽  
Cutoff Walls ◽  
Plastic Concrete ◽  
Wall Construction ◽  
Using Data

Concrete cutoff walls are usually constructed using a panel-by-panel technique in which primary panels are constructed with space between them and then secondary panels are constructed and inserted in the spaces. A small thickness of residual bentonite cake from the slurry used during excavation usually remains in the construction joints between adjacent primary and secondary panels. The thickness of such bentonite-filled joints should be minimized in terms of the performance of the cutoff wall in controlling seepage. This research experimentally evaluated the effects of a number of design and construction parameters on the thickness of the bentonite cake using data from a case study (the cutoff wall of Karkheh Dam). A physical model test was developed and a number of tests were conducted. The test results showed that parameters such as age of the primary panels, cement content of the slurry, quantity of additives in the slurry, and circulation versus noncirculation of the slurry are responsible for the thickness of the bentonite cake. The results are presented and analyzed.Key words: cutoff wall, plastic concrete, bentonite slurry, bentonite cake, physical model.

Laboratory test results on self-hardening grouts for flexible cutoffs

1984 ◽  
Vol 21 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Robert P. Chapuis ◽  
J.-Jacques Paré ◽  
André A. Loiselle
Keyword(s):  
Experimental Program ◽  
Test Results ◽  
James Bay ◽  
Cement Slurry ◽  
Cutoff Wall ◽  
Hydroelectric Project ◽  
Solid States ◽  
Bentonite Slurry ◽  
Laboratory Test Results ◽  
Cutoff Walls

The addition of cement to a bentonite slurry gives a complex material called self-hardening grout which slowly sets to become a clay-like solid. The properties of these mixes are highly dependent on the bentonite and the cement used. Most information available up to now comes from European countries where the technique has been developed. As very little information was available about such mixes in North America, an experimental program was initiated to study their applicability for cutoff walls of certain dams of the James Bay hydroelectric project. The present paper describes the characteristics of different mixes tested in their fluid and solid states. Keywords: bentonite, cement, slurry, cutoff wall.

scholarly journals Construction and Monitoring of Cement/Bentonite Cutoff Walls: Case Study of Karkheh Dam, Iran

2019 ◽  
Vol 41 (4) ◽  
pp. 184-199 ◽  
Author(s):  
Iman Faridmehr ◽  
Mohammad Reza YazdaniPour ◽  
Mohammad Javadi Jokar ◽  
Togay Ozbakkaloglu
Keyword(s):  
Low Permeability ◽  
High Ductility ◽  
Cutoff Wall ◽  
Water Leakage ◽  
Embankment Dams ◽  
Cutoff Walls ◽  
Plastic Concrete ◽  
Dam Operation ◽  
3D Software

AbstractWater seepage is one of the most important features of embankment dams. To prevent and reduce seepage, it is necessary to seal the dam. Plastic concrete cutoff walls are one of the most efficient methods in waterproofing the foundation of embankment dams on permeable alluvial substrates. Sufficient resistance to loads, low permeability to maintain dam sealing, high ductility compatible with the foundation and deformation under load without cracking are the main requirements in plastic concrete cutoff walls. In this paper, the construction and implementation of the cutoff wall of Karkheh Dam, which is one the world’s largest water sealing projects, was studied. In addition, a numerical model using Seep-3D software was developed to evaluate the efficiency of the cut-off wall to decrease the seepage over the dam’s foundation. The numerical results validated by instrumentation statistics resulted from 17-years dam operation. According to the results, after the drainage of the reservoir, the cutoff wall optimally reduced the hydraulic gradient by 0.08 from 2.35 and the water leakage by 3.1 m/s from 18.3 m/s.

Design of a hydrodynamic leachate containment system

1989 ◽  
Vol 16 (5) ◽  
pp. 615-626 ◽  
Author(s):  
M. D. Haug ◽  
D. J. L. Forgie ◽  
S. L. Barbour
Keyword(s):  
Contaminant Transport ◽  
Water Table ◽  
High Water ◽  
Groundwater Table ◽  
Cutoff Wall ◽  
Transport Modelling ◽  
High Water Table ◽  
Cutoff Walls ◽  
A Site

This paper presents the design concept for a case study sanitary landfill on a site that would not normally have been approved owing to the presence of a high water table. In this design, the base of the landfill was intentionally placed below the water table. A massive 2.5 m wide, 2.5 m high cutoff wall and a 0.3 m thick liner with hydraulic conductivities of approximately 5 × 10−10 m/s were constructed of recompacted glacial till to limit both groundwater intrusion into the landfill and leachate migration out of the landfill. In this case study, the landfill base was placed below the water table to (i) provide a relatively inexpensive source of cover material and (ii) use the hydrodynamic gradient from the high water table to help contain the leachate. Finite element modelling of the seepage and contaminant transport, for alternate designs for lined and unlined landfills placed above and below the groundwater table, is shown to confirm a previous, less-sophisticated, estimation that placing a lined landfill below the groundwater table has definite advantages in reducing both leachate seepage and contaminant transport. Key words: landfill, leachate, hydrodynamic containment, liners, compacted earth cutoff walls, seepage and contaminant transport modelling.

scholarly journals WAVE RUN-UP PREDICTION VS. MODEL TEST RESULTS: A COMPARISON

1988 ◽  
Vol 1 (21) ◽  
pp. 47 ◽  
Author(s):  
Peter E. Gadd ◽  
Victor Manikian ◽  
Jerry L. Machemehl
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Large Scale ◽  
Physical Model Test ◽  
Roughness Coefficient ◽  
Wave Steepness ◽  
Test Results ◽  
Shore Protection ◽  
Run Up

Large-scale physical model test measurements of wave run-up are compared with wave run-up prediction derived from the Shore Protection Manual (SPM). Noteworthy discrepancies between the results of these two methods have been identified that include substantial overestimation of wave run-up elevations using the SPM approach, and computation of roughness coefficient values that vary as a function of wave steepness. The slope armors tested in the study at model scales of 1:3 and 1:4 include linked concrete matting and overlapped gravel-filled fabric bags.

The Seepage Behavior of Composite Geo-Membrane & Cutoff Wall Applied in Three Gorges Project

2011 ◽  
Vol 186 ◽  
pp. 146-150
Author(s):  
Kai Chang Sun
Keyword(s):  
Composite Materials ◽  
Primary Objective ◽  
Three Gorges ◽  
Test Results ◽  
Cutoff Wall ◽  
Working Mechanism ◽  
Second Stage ◽  
Plastic Concrete ◽  
The Difference ◽  
Mechanical Characters

The primary objective of this paper is to study the seepage behavior of the cutoff wall and the working mechanism of the composite geo-membrane applied in the second stage cofferdam of the Three Gorges Dam. The mixture proportion of the plastic concrete applied in the cutoff wall is researched and a recommended proportion is put forward. The difference between the composite geo-membrane and single geo-membrane concerning mechanical strength and permeability is detected and reasons which lead to the difference are found. The test results indicate that the mechanical characters of the composite geo-membrane have been improved remarkably. It is demonstrated that the deformation ratio plays an important role in terms of the permeability by bursting test. The behavior of the composite geo-membrane and the effect of the composite materials in different work-stage are studied and the influence of the elasticity of the composite materials on the practical application of the composite geo-membrane is analyzed. It is found that the strength is not just the superposition of the strength of composite materials and membrane.

scholarly journals Monitoring system of student performance using data warehouse (Case study: INSTITUT TEKNOLOGI SUMATERA)

2018 ◽  
Vol 4 ◽  
Author(s):  
Ahmad Luky Ramdani ◽  
Raidah Hanifah ◽  
Okta Pilopa
Keyword(s):  
Student Performance ◽  
Data Warehouse ◽  
Monitoring And Evaluation ◽  
Test Results ◽  
Test Scenario ◽  
Monitoring Process ◽  
Using Data ◽  
Academic Year

Improving the quality of learning is one of the things that must be achieved in the college academic process. To achieve this, monitoring and evaluation of the results of the learning process is needed, namely by looking at student performance. Based on this, the research aims to develop a university data warehouse with student performance objects that will be used by the board application for the monitoring process. The application was successfully developed with several main features, namely: a) displaying the number of students based on year, region and the entrance to college, b) displaying a comparison of the number of students in each academic year based on student status , d) display student performance every academic year and e) KPI values based on needs analysis. These features have been tested using the blackbox approach and the test results show that the features work properly and produce outputs in corresponding to the test scenario.

scholarly journals Application of a Bentonite Slurry Modified by Polyvinyl Alcohol in the Cutoff of a Landfill

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Guozhong Dai ◽  
Yanmin Sheng ◽  
Yutao Pan ◽  
Guicai Shi ◽  
Shujin Li
Keyword(s):  
Polyvinyl Alcohol ◽  
Adsorption Capacity ◽  
Permeability Coefficient ◽  
Cutoff Wall ◽  
Treatment Results ◽  
Bentonite Slurry ◽  
Cutoff Walls ◽  
Adsorption Capability

Soil-bentonite cutoff walls are usually used to contain the contaminants of landfills. The pumpability, permeability, and adsorption capability of the slurry are all crucial to the performance of the cutoff wall. In this study, the effect of polyvinyl alcohol (PVA) was used to improve the performance of bentonite slurry. A series of lab tests were conducted to evaluate the pumpability, permeability, and adsorption capacity with different concentrations of PVA treatment. Results show that the addition of PVA can increase the fluidity and pumpable period of slurry, which facilitates the casting and grouting during construction. The addition of PVA also helps to reduce the permeability coefficient of slurry and improve the adsorption capability which enhances the cutoff performance of the walls.

Effect of Phosphate Dispersant Amendment on Workability of Ca-Bentonite Slurry for Slurry Trench Cutoff-Wall Construction

2017 ◽  
Vol 47 (4) ◽  
pp. 445-452 ◽  
Author(s):  
Yu-Ling Yang ◽  
Yan-Jun. Du ◽  
Krishna R. Reddy ◽  
Ri-Dong Fan
Keyword(s):  
Cutoff Wall ◽  
Bentonite Slurry ◽  
Slurry Trench ◽  
Wall Construction
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