Field Survey, Detailed Study and Geotechnical Investigation at Dhedre and Lendada Tunnel, Bridge and Subgrade / Road Slope Stability at Kathmandu- Terai/Madhesh Fast Track (Expressway) Road Project

Description

The main purpose of the field survey works is to develop a survey map of the area, preparation of meteorological datasheet, identify the hydrological and hydraulic condition of the river at proposed bridge sites, investigate probable seismic hazard of the proposed bridge, and geotechnical investigation of Dhedre and Lendada Tunnel, Bridges and 1016.5m Subgrade is to investigate the subsurface geological conditions, presence of groundwater, the thickness of rock bands, depth of overburden, etc. The geotechnical investigation for Dhedre and Lendada (2-Twin) Tunnels, Bridge, and Subgrade / Road Slope Stability comprises of 7 boreholes. The maximum depth of geotechnical exploration is 377m.

Description of Actual Services Provided in the Assignment:

1. Preparation of Survey Map including
   • 1:2000 Scale Topographic Survey Map along Tunnel line – 3.2 km2
   • 1:500 Scale Survey for tunnel portal area densification – 0.16 km2
   • 1:500 Scale Topographic Survey and Map of bridge pier and abutment – 0.2 km2
   • Forth-grade Control Points survey layout – 10 Nos
   • First-grade Control Points layout – 10 Nos
   • Profile Survey – 4.65 km
   • Cross-Sectional Survey – 500 Sections

Riverbed Section Survey – 5.5 km

2. Meteorological Survey
   • Annual Rainfall Study, Wind Speed Study, Temperature Study
3. Hydrological, Hydraulics and Scour Survey
   • Study of Catchment Characteristics
   • Design Flood
   • Sediment Yield
   • Hydraulic Simulation
   • Hydraulic Design
   • Scour Calculation
   • River Protection
4. Seismic Hazard Assessment of Bridge and Project Area
   • Seismo Tectonic Data Analysis
   • PSHA Model and Analysis
   • Design Response Spectra Analysis

5. Geological Mapping of Area including RMR & Q calculation for Tunnel 1:2000 Scale -3.2 km2
6. Geotechnical Investigation (drilling works and laboratory tests) is to investigate the subsurface geological conditions, water pressure (Lugeon Test for permeability), presence of groundwater, the thickness of rock bands, depth of overburden, etc.