Thesis Abstract

All Thesis Abstracts

Laboratory Investigation on Improving California Bearing Ratio Value of Weak Subgrade Soil Modified with Fly Ash, Waste Concrete Fines and Road Dust

Riju Adhikari

Asst. Prof. Rajesh Khadka

Trip Based Mode Choice Modeling : A Case Study of Biratnagar Metropolitan City

Sunil Khatri

Er. Rajesh Khadka

Evaluation of Traffic Congestion Costs of New Baneshwor to Old Baneshwor Road Section

Ankur Bhatta

Prof. Dr. Thusitha Chandani Shahi

Analysis of Pedestrian Gap Selection Behavior at Selected Crosswalks of Unsignalized Intersection:A Case Study of Durbar Marg and Naya Bazaar of Kathmandu

Sujana Thapaliya

Prof. Dr. Thusitha Chandani Shahi

Evaluation of Combined Effect of Flakiness and Elongation in the Strength Parameters of First Coat Stone Chippings for Double Bituminous Surface Treatment

Parbesh Manandhar

Er. Rajesh Khadka

Determination of Relationship between Thickness of Base Course and Different Physical Properties of Base Material in the Construction of Flexible Pavement

Aashma Neupane

Asst. Prof. Rajesh Khadka

Cycle Time Analysis of Drill and Blast Method Tunnel Construction based on Geological Condition in Hydropower Projects in Nepal

Student: Suraj Pant

Supervisor: Er. Satya Ram Jyakhwa

Submitted Date: November, 2023

Abstract

Tunnelling construction processes are considered to be quite complex. They involve many variables which interact with each other and the resourced used. Drill and Blast method is one of the popular methods used in tunnel construction in Nepal. In order to understand and determine the tunnelling construction processes time the thesis analyzed the cycle time and derived productivity rate equation based on the geological conditions by analyzing the data from six hydropower projects. Field measurement data from two projects were used to determine the equation and root mean square error was used to validate equation. The research obtained that out of six projects five projects had lesser root mean square error with the derived equation while comparing with the actual productivity rate which validates the equation. The thesis identified twenty-six factors that impact the cycle time and from the questionnaire analyzed the responses using the RII technique, determined Spearman’s correlation and performed t-test for establishing the significance. The five major factors identified were; long breakdown time of critical machines, geological conditions, design and scope changes, inexperienced and incompetent contractors and ignoring consultant instruction by contractors. The niche is a temporary structure build in excavation phase of the tunnel, commonly with the same diameter of tunnel and length of the hauling vehicle, with its main function to organize the equipment and reduce mucking distance within the tunnel. The thesis determined that in medium diameter tunnels the optimal mucking time is achieved when distance from niche and tunnel face is in the range of 150 to 175 meters. It is recommended to use the result of this thesis for estimation of the tunnel construction time of medium diameter (3m to 3.8m) sized hydropower project applying full face excavation by drill and blast method which can accommodate moderate size equipment. It is recommended to perform a detailed geological investigation before starting the construction of the tunnel.

Keywords

Tunnel, Cycle Time, Productivity rate, Rock class, Niche

THESIS ABSTRACT