scholarly journals Rock Support Design for the Khimti I Hydropower Project

2000 ◽  
Vol 22 ◽  
Author(s):  
S. C. Sunuwar ◽  
G. L. Shrestha ◽  
B. O' Neill
Keyword(s):  
Cost Effective ◽  
Concrete Lining ◽  
Hydropower Project ◽  
Rock Support ◽  
Specific Design ◽  
Support Design ◽  
Rock Classification ◽  
Rock Bolting ◽  
Cast Concrete ◽  
Drill And Blast

The Khimti I Hydropower Project (KHP) is the first project where the Norwegian Method of Tunnelling (NMT) was applied in Nepal. The method was found to be appropriate for drill-and-blast tunnels in jointed, fractured, and sheared rocks, which tend to overbreak. A combination of rock bolting with wet fiber reinforced shotcrete is the main rock support method in the NMT. In exceptionally poor rock (with squeezing conditions) reinforced ribs of shotcrete with a concrete invert were generally found to be a more efficient and cost effective. Cast concrete lining was also used occasionally at the KHP, mainly in overbreak areas with high groundwater discharge. The main advantage of the NMT is that each stretch of tunnel is evaluated using the Q-System of rock classification and then only the required amount of support is applied. This procedure takes optimum advantage of the self-supporting capacity of the rock. There were some problems encountered during application of the NMT at the KHP, but the adoption of 10 site -specific design principles made the method more practical and effective. It was generally experienced that the NMT was simple to use and gave appropriate guidelines that could be applied across a very broad range of rock conditions. At Khimti, the peak excavation rates reached 63 m/week and 72 m/week in 25 m2 and 14 m2 tunnels, respectively. The average excavation rates (including full support) were 10 m and 35 m per week in "Extremely Poor" and "Poor to Fair" rock conditions, respectively.

scholarly journals The Efficiency of Large Hole Boring (MSP) Method in the Reduction of Blast-Induced Vibration

2021 ◽  
Vol 11 (4) ◽  
pp. 1814
Author(s):  
Min Seong Kim ◽  
Sean Seungwon Lee
Keyword(s):  
Urban Areas ◽  
Cost Effective ◽  
Base Case ◽  
Large Hole ◽  
Promising Alternative ◽  
Geological Information ◽  
Drill And Blast ◽  
Smooth Blasting ◽  
Alternative Designs ◽  
Blasting Method

Drill and blast is the most cost-effective excavation method for underground construction, however, vibration and noise, induced by blasting, have been consistently reported as problems. Cut blasting has been widely employed to reduce the blast-induced problems during underground excavation. We propose that the large hole boring method using the state-of-the-art MSP (Multi-setting smart-investigation of the ground and pre-large hole boring) machine (“MSP method”) can efficiently improve vibration reduction. The MSP machine will be used to create 382 mm diameter empty holes at the tunnel cut area for this purpose. This study assessed the efficiency of the MSP method in reducing blast-induced vibration in five blasting patterns using a cylinder-cut, which is a traditional cut blasting method. The controlled blasting patterns using the MSP method demonstrated up to 72% reduction in blast-induced vibration, compared to the base case, Pattern B, where only cylinder-cut and smooth blasting method were applied. Therefore, the MSP method proves to be a promising alternative for blasting in sensitive urban areas where non-vibration excavation techniques were initially considered. Geological characteristics of 50 m beyond the excavation face can be acquired through the proposed real-time boring data monitoring system together with a borehole alignment tracking and ground exploration system. The obtained geological information will be a great help in preparing alternative designs, and scheduling of construction equipment and labour during the tunnel construction.

scholarly journals Effect of Modulus of Bituminous Layers and Utilization of Capping Layer on Weak Pavement Subgrades

2020 ◽  
Vol 6 (7) ◽  
pp. 1286-1299
Author(s):  
Muhammed Alzaim ◽  
Abdulgazi Gedik ◽  
Abdullah Hilmi Lav
Keyword(s):  
Material Properties ◽  
Road Construction ◽  
Cost Effective ◽  
Flexible Pavement ◽  
High Modulus ◽  
Specific Design ◽  
Capping Layer ◽  
Traffic Loads ◽  
Number Of Layers ◽  
Pavement Foundation

The majority of the world’s highways consist of a flexible pavement commonly built of several layers (both asphaltic and granular) that have been laid over a pavement foundation known as the subgrade. A subgrade that is considered to be of a satisfying bearing capacity is expected to restrict not only the immediate distresses occurring during the construction phases, but also later deformations appearing during the service life of the pavement as it subjected to traffic loads. If the subgrade proves to be structurally weak, the highway’s flexible pavement can be supported by adding such modifications as a capping layer, which serves to greatly reduce the stress being applied to the pavement. This study aims to further our knowledge about maximum pavement functionality by investigating those parameters considered crucial to pavement design: the correspondence of material properties, the number of layers, and the layer thickness. These parameters were analyzed to determine the best performing composition, while also considering the financial aspects of road construction. To achieve such an aim, we chose to use KENLAYER software to assist us in determining the design of a flexible pavement in line with a specific Equivalent Single Axle Load (ESAL). The KENLAYER configuration provided us with the required ESAL targets for specific design lives. We next calculated the relative costs of these targets and chose those that proved to be most cost-effective and economical. The results indicate that when considering feasible pavements to meet a design of high ESAL applications, those utilizing high modulus asphaltic materials are most suitable for subgrade CBR of at least 3%, while weaker subgrade constructions must be provided with a capping layer.

scholarly journals Previous classification of rock mass surrounding underground excavations and rock support design using block models

2021 ◽  
Vol 74 (4) ◽  
pp. 511-519
Author(s):  
Iure Borges de Moura Aquino ◽  
Rodolfo Renó ◽  
Roberto Mentzingen Rolo ◽  
André Cezar Zingano ◽  
Hernani Mota de Lima
Keyword(s):  
Rock Mass ◽  
Underground Excavations ◽  
Rock Support ◽  
Support Design ◽  
Block Models

scholarly journals Technologies for obtaining energy from micro-hydropower resources

2020 ◽  
Vol 2 (4) ◽  
pp. 124-133
Author(s):  
Cristian Purece ◽  
Vasile Pleşca ◽  
Lilica Corlan
Keyword(s):  
Renewable Energy ◽  
Cost Effective ◽  
Hydraulic Turbine ◽  
Environmental Benefits ◽  
Hydropower Plant ◽  
Hydropower Project ◽  
Renewable Energy Resources ◽  
Optimum Selection ◽  
Hydropower Potential ◽  
Selection Mode

Currently the global demand for electricity and drinking water is constantly increasing. Given its many economic, social and environmental benefits, hydro energy will be an important contributor to the energy mix of the future. Isolated areas, heavily underdeveloped regions, disaster-affected areas have a common need of easy-to-use means to generate electricity. The most efficient way to meet these needs involves the use of various renewable energy resources available locally. One of the main sources of renewable energy is hydro energy, more specifically micro-hydro energy. However, hydropower projects involve various considerations at different levels of project implementation. To make the most of the available hydropower potential, new models of hydraulic turbines were developed. For a cost-effective and efficient hydropower project, the selection of the hydraulic turbine must be optimally studied. The objective of the present work is to carry out a review of the optimum selection mode of the hydraulic turbine that equips a micro hydropower plant (MHP).

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