Treatment of Seepage through Vendarasankulum Twin Reservoir in Eastern Sri Lanka - Cost Comparison of Alternative Techniques (original) (raw)
Related papers
2017
Development of Left Left Main Dam project Sindangheula Dam, Banten which is the Urugan type Dam in need of geological study with the method of Grouting consisting of 2 Blocks. This study is based on geological conditions and technical properties of rocks, especially to minimize water disaster or failure and development. Development Left Bank Of Sindangheula Dam, Banten which is the Urugan type Dam in need of geological studies with the Grouting method consisting of 2 Blocks. This study is based on the geological condition and the technical nature of the rocks, especially to minimize disaster / seepage or development failure. Based on the identification of the composition consisting of the Vitric Tuff and the LithicTuff which has a low permeability and there is a minor structure in the form of a sturdy that has orientation Southeast-Northwest and the nature of rock technique which has a RQD between 20-70% and Lugeon value between 5-10 that fall into the category of need in Grouting and indicate that the research area is prone to disaster or water seepage so that it needs the use of Grouting method to minimize disaster. After doing the activities of Ground Trial and Cement Injection, the need to calculate the effectiveness of the use of Grouting itself in every block. Results from 2 research blocks in which each block has 1 Pilot Hole and 1 Check Hole with 3-4 stages. On Block 1 the effectiveness figure is 56.90% (Stage 1); 42.71% (Stage2); 64.40% (Stage3). On Block 2 the effectiveness figure was 31.54% (Stage1); 46.90% (Stage 2);75.13% (Stage 3). From the number of effectiveness in getting and in comparison with "The Effectiveness of Grouting and Its Effect" can be concluded that the effect of Grouting Effectiveness is Medium-Good.
An application of grout curtains to the Dalaman -Akkpr Dam
International Journal of Physical Sciences, 2011
Grouting is one of the most popular methods used to control water leakage in fill dam constructions. Geological and geotechnical properties of the rock/soil to be grouted are important parameters influencing the design of the grouting. In this study, geotechnical properties of Dalaman-Akköprü Dam's base rock and the grouting procedure have been investigated in view of their suitability to grouting. In the study, detailed investigations of the foundation injection applications were made into the main rock, the reasons and types of application are made. The materials used in grouting and the grouting pressures are investigated at site and the obtained results are presented. The improvement study and application type is evaluated and background information on different applications of grouting is presented.
Evaluation of Grout Curtain Performance and Seepage Behavior in Doosti Dam, Iran
2015
Design and construction of civil structures such as dams require deep understanding of geological and geotechnical engineering conditions of rock masses in their site. Doosti Dam site consists of sedimentary rocks such as calcareous marl, siltstone, sandstone and sandy limestone of Mesozoic (Cretaceous) and early Tertiary of the Kopet-Dagh basin. In this study, permeability and hydraulic conductivity conditions of dam site were evaluated based on Lugeon tests and were presented as maps. Additionally, rock mass discontinuities in dam site and their properties were determined. The effects of geological engineering properties of discontinuities and permeability of different rock units on grout takes in the grout curtain were assessed. To compare the results, grouting performance was presented in the form of iso-cement take curves in the curtain rows. Finally, areas with poor performance were determined based on the obtained information. These points are pathways for water escape and po...
EFFECTIVENESS OF GROUTING MATERIALS FOR WATER SEEPAGE CONTROL
One of the major concerns facing dam is the repair of their structures to prevent the seepage under them. In previous years, many existing dams have been treated by grouting, but with varying degrees of success. One of the major reasons for this erratic performance is the unsuitable selection of the grouting materials to reduce the seepage. Grouting is an effective way to strengthen of the permeability of the soil to reduce the seepage. The purpose of this paper is to focus on the efficiency of current available grouting materials and techniques from construction, environmental and economical point of view. The seepage reduction usually accomplished by either chemical grouting o r cementious grouting using ultrafine cement. In addition, the study shows a comparison between grouting materials according to their degree of permeability reduction and cost. The application of seepage reduction is based on the permeation grouting using grout curtain installation. The computer program (SEEP/W) is employed to model a dam rested on sandy soil, using grout curtain to reduce seepage quantity and hydraulic gradient by different grouting materials. This study presents a relationship that takes into account the permeability of the soil, grout curtain spacing and a new performance parameter that can be used to predict the best selection of grouting materials for seepage reduction
An application of grout curtains to the Dalaman- Akköprü Dam
2011
Grouting is one of the most popular methods used to control water leakage in fill dam constructions. Geological and geotechnical properties of the rock/soil to be grouted are important parameters influencing the design of the grouting. In this study, geotechnical properties of Dalaman-Akköprü Dam’s base rock and the grouting procedure have been investigated in view of their suitability to grouting. In the study, detailed investigations of the foundation injection applications were made into the main rock, the reasons and types of application are made. The materials used in grouting and the grouting pressures are investigated at site and the obtained results are presented. The improvement study and application type is evaluated and background information on different applications of grouting is presented.
Assessment of Relationship Between Grouted Values and Calculated Values in the Bazoft Dam Site
Geotechnical and Geological Engineering, 2017
Seepage through foundation and abutments of a dam can potentially result in a waste of the water stored in dam reservoir, erosion of foundation materials, and development of uplift pressure in dam foundation which, consequently, threatens the long-term stability of the dam. In this study, the grout volume is estimated based on parameters such as joint aperture, the maximum penetration length of the grout, and calculated grout take in Bazoft dam site. Bazoft Dam is a hydroelectric supply and double-curvature arch dam with a height of 211 m located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of Bazoft dam site consists of Asemari Formation (limy marl and marly lime), in the middle and upper parts of left abutment, and Jahrom Formation (limestone and dolomite) in the right abutment, river bed, and lower part of left abutment. The joint apertures were calculated based on the permeability and the joint spacing. Next, the maximum penetration length of the grout and grout volume were calculated. Using a statistical analysis, the relationship of the joint aperture, maximum penetration length, and the calculated grout volume with real grout take was also investigated. The results show that the grout take can be predicted with appropriate accuracy based on the calculated grout volume.
Effect of using grouted vertical barrier on seepage characteristics under small hydraulic structures
Alexandria Engineering Journal, 2020
This study investigated the effect of using Grouted Vertical Barrier (GVB) on the seepage characteristics (uplift force, seepage rate, and exit hydraulic gradient) under small hydraulic structures. The GVB's variables, viz., position, depth, width and hydraulic conductivity, were studied experimentally using sand model and numerically employing SEEP/W software. A parametric study investigated several cases of the variables after numerical model verification. The results depicted that the heal and toe ends were the best positions for uplift force and exit gradient, respectively. The maximum reduction in the seepage occurred at both ends. The seepage characteristics swiftly decreased by increasing the GVB's depth in the pre-mentioned best positions. Upsurge of the GVB's width sequentially reduced the exit gradient and the seepage rate, whilst negatively impacted the uplift force. Declining the ratio between the hydraulic conductivity of the GVB (K) and the reference soil one (K o) significantly lowered the seepage until reaching a stationary proportion K/K o = 1EÀ4. Beyond this, decreasing K/K o ratio do-nothing. Through regression analysis, three equations were developed to estimate the seepage characteristics affected by GVB's variables. The indications of comparative studies revealed a better effect of the GVB compared to any of the sheet pile or the upstream blanket.
Advances in Civil Engineering, 2022
Seepage from the earth dam's body reduces the amount of water in the dam's reservoir and threatens its stability. In this paper, the earth-type Sattarkhan Dam on the Aharchai River has been investigated. In this regard, the SEEP/W model from the GeoStudio 2018 software suite was used for modeling. is study examines the e ects of various lengths and positions of cuto wall and horizontal drainage on seepage, uplift pressure, and exit gradient. Increasing the length of the cuto wall reduces seepage in both sections, with a more signi cant e ect on Section 2; it also decreases the uplift pressure and the exit gradient. Changing the position of the cuto wall has a signi cant e ect on seepage uctuations in Section 1 but has no e ect on seepage in Section 2; in positions 2 to 7, the uplift pressure values are nearly identical, and the exit gradient is most signi cant at position 1 and least at position 2. Increasing the horizontal drainage's length increases seepage, reduces uplift pressure, and increases the exit gradient. e closer proximity of the horizontal drainage position to the dam's core increases seepage and decreases uplift pressure and exit gradient. Finally, it is concluded that the construction of a cuto wall and horizontal drainage with appropriate lengths and positions reduces risk and improves the stability of earth dams.
American Journal of Applied Sciences, 2009
Problem statement: The dam body and foundation seepage is one of the important points in design parameters. This index is related to the permeability. There fore permeability is one of the basic parameter in design grout curtain, prevent water escape from foundation and avoid negative seepage pressure in borrow materials, so grouting is used. Grouting means injected materials like cement or chemical materials under pressure to rock or soil layers. Approach: Purpose of grouting is treatment fractures, fissures, increase strength and decrease seepage. Grout curtain is used for sealing beneath dam body and other structure to obtain above aspects. Results: The present research dealing to study the geotechnical characteristics and conditions of two damsites (Kavar and Sheshpir dam) regarding to their permeability and groutability. Permeability in rock mass is controlled by jointing and their characteristics. The Kavar dam may be constructed on Gareh Aghaj river. This site is located in 40 km southwest of Fars province, Iran. The river flow direction is parallel to the local syncline axis. The main geological features of damsite are faults, fractures and gypsum lenses that they may lead to water escape from reservoir. The rocks in the right abutment of the dam are heavily crushed with low strength. Therefore it is expected that water escape from this zone and some parts of dam axis may happen. This is approved from boreholes logs analysis and Water Pressure Tests (WPT). The other dam which called Sheshpir is located in west of Shiraz, Iran. Regarding to structural geology of this site, two large anticlines are extended in general direction of Zagros mountain range (northeastsouthwest). The geology index features are karstic and jointed rock with faults. In general, regarding the grout-curtain design for each case, it is necessary to evaluate the volume of grout and injection system. Because of complexity of local structural geology especially rock foundation, it is difficult to estimate above-mentioned parameters. Conclusion/Recommendations: Therefore, through a number of WPT in both sites, the Permeability and hydro fracture tests results were used in the foundation for the design of the grouting program. using SPI rock classification systems, it is possible to identify the karstic features of the formation and the relationships between the permeability and groutability. This method that first expressed by foyo identify the special classification for grouting. In this system use results of Water Pressure Test (WPT) and Rock Quality Design (RQD) simultaneously. With the help of these two parameters rock class and grout complex is identified.
Design of grout curtain for temporary embankments on rock foundation
Geomechanics and Geoengineering, 2020
The design of curtain grouting for dams on rock foundations and the importance of finite element seepage analysis is reported by highlighting a case study of the upstream cofferdam of Gulpur Hydropower Project, Pakistan. Results from seepage analysis decreased the scope of curtain grouting by almost 3 times as compared to initial scope based on results from empirical correlations and water pressure tests. The total grouting holes were decreased from 185 to only 66 and this meant a decrease of construction time by 72% and saved a huge amount of capital and resources as well. The performance of the grout curtain is concluded to be satisfactory, for an operation phase of 3 years which includes two major floods as well and during this period, no visible erosion, quick condition or saturation was found on the downstream end. The paper concludes that if the safety criteria are satisfied, even with high inflows of the river, the scope of curtain grouting can be partially reduced or completely eliminated for temporary dams having an operational life of 1-5 years.