This document presents a thesis proposal for assessing the stability of the headrace tunnel of the Khimti-2 Hydroelectric Project in Nepal. The objectives are to study the engineering geology of the tunnel area, conduct rock mass classification surveys, determine seismic impacts through numerical modeling, and review the current tunnel supports. The methodology involves a literature review, site visits, data collection, modeling, and defense. The expected outcomes are an assessment of tunnel stability and support recommendations considering seismic effects. Some limitations are not being able to collect all face map data. The work schedule outlines tasks from June to September 2023.

1. Institute of Engineering, Tribhuvan University, Nepal
Stability Assessment and Review of Applied Support
at Headrace Tunnel of Khimti-2 Hydroelectric Project
TRIBHUVAN UNIVERSITY
INSTITUTE OF ENGINEERING
Pashchimanchal Campus
Thesis Proposal Presentation
Supervisor:
Sangit Lamichhane
Department of Civil Engineering,
Pashchimanchal Campus, IOE, TU
PAS078MSRTE016
Date: 28 May, 2023

2. 2 Institute of Engineering, Tribhuvan University, Nepal
Contents
1. Introduction
2. Statement of Problem
3. Objectives
4. Methodology
5. Expected Outcomes
6. Limitations
7. Work Schedule
8. References

3. 3 Institute of Engineering, Tribhuvan University, Nepal
1. Introduction
Description of Project
Boundry
Khimti River
K2HEP
Location
Ramechhap
District
Dolakha
District

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1. Introduction
Description of Project Sn General Project Details
1. Project Boundary 27°33’07”N to 27°35’13”N
86°09’26”E to 86°14’28”E
2. Location Border of Dolakha & Ramechhap
District, Right Bank of Khimti River
3. Headrace Tunnel Inverted D-Shaped with
width=4m,Length=6.321
4. Power Production 48.8 MW
5. Geology of Project
area
Lesser Himalayan Midland zone of
Central Nepal
Jiri thrust, Midland Thrust
Rock Available Augen Gneiss, Schistose Gneiss Schist
and Banded gneiss. Intercalation of
these rocks is frequently seen.

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1. Introduction
Rock Mass Quality
 Detailed information regarding the strength qualities of the rock and in-situ stresses are
not available during initial stage of project.
 As a result, empirical techniques such as rock mass classification systems are used to
carry out the preliminary design of the tunnel support system.
 Depending upon the level of preconstruction phase engineering geological investigations,
the predicted and actual rockmass may vary accordingly on the site.
 If Supports are less then required, slowly advances into the tunnel without perceptible
volume increase.
 The underground structures are less susceptible to damage due to earthquakes than
surface structures due to various factors such as reduction in ground motion with depth
and consequent reduction in seismic coefficient but the impact of the seismic hazards
should be properly studied.

6. 6 Institute of Engineering, Tribhuvan University, Nepal
2. Statement of Problem
 Limited field observation, testing result and not sufficient preconstruction
geological investigation
 Nepal has Complex geological setup while moving from south to north.
Preconstruction investigation conducted at one location of the tunnel alignment
may not be valid for other location, which may hamper overall construction cost
and time.
 Supports are given only based on support Chart of Q-system, which was
developed from the case histories in tunnels other than Nepal Himalaya.
 Nepal lies in one of the most seismically active regions in the world where
earthquakes of high magnitude occur at regular intervals causing significant
damages to structures.

7. 7 Institute of Engineering, Tribhuvan University, Nepal
3.Objectives
General Objective
 Assess the stability condition of the headrace Tunnel
Specific Objective
 To study about the engineering geological parameters of the area around the tunnel
alignment.
 To carry out the rock mass classification survey at the surface as well as inside the
tunnel and compare the results.
 To determine the seismic impacts on tunnels through Numerical Approaches i.e Phase2
and review the current supports in the tunnel

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4. Methodology
Fig: Methodology flow diagram

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5.Expected Outcomes
The expected outcomes from this Research will be assessment of the
stability condition of headrace tunnel and suggestion of required
support considering seismic effect via numerical modeling.

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6.Limitations
 I would not be able to collect all the face map data myself and I will collect these from
the project

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7.Time Schedule
Sn Task June 1-June
-15
June16-
June30
July 1-July
-15
July16-
July-30
Aug 1-Aug
-15
Aug 16- Aug-
30
Sept 1-Sept -
15
Sept 16- Sept-
30
1 Literature Review,
Submission of Final
proposal, Consultation
with supervisor
2 Site Visit, Documentation
and Modeling
3 Mid-term Defense
4 Correction and
Modification and other
works
5 Final Project Defense

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8.References
 Wyllie, D.C. and Mah, C., 2014. Rock slope engineering. CRC Press.
 Hoek & Marinos,2000, Predicting tunnel squeezing problems in weak heterogeneous rock masses
 K. K. Panthi and B. Nilsen, Comparison between predicted and actual rock mass conditions: a review based on tunnel projects in Nepal Himalaya
 Hoek, E., 2007. Practical Rock Engineering.
 Hudson, J. A. & Harrison, J. P., 1997. Engineering Rock Mechanics.
 Panthi, K. (2006). Analysis of engineering geological uncertainties related to tunneling in Himalayan rock mass conditions. NTNU, Norway.
 Tshering, K. (2012). Stability assessment of headrace tunnel for Punatsangchhu II Hydropower Project, Bhutan. NTNU Norway 150: MSc Thesis.
 D.U. Deere, R.B. Peck and H.W. Parker. Design of Tunnel Support Systems. University of Illinois.
 Shrestha, G. (2006). Stress induced problem in Himalayan Tunnels with Special reference to Squeezing. Trondheim, Norway: Doctoral Thesis, NTNU
 N. Dawadi & A.B Singh,2020, Prediction of Rock Burst, Squeezing and Support Design using Three-Dimensional and Conventional Methods along Headrace Tunnel in Balephi,
Nepal
 Santosh Subedi,2022 Rock Engineering Assessment along the Headrace Tunnel of Khimti2 Hydroelectric Project,MSc thesis
 Sivarajan T. K. Seismic load considerations in the design of underground structures for hydropower projects in the himalayan region. Recent Advances in Rock Engineering, 2016.
 Nepal Earthquake 25 April 2015: Hydro projects damaged, risks and lessons learned for design considerations, Subas Chandra Sunuwar,2018

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Thank YOU!!