Name: Geotechnical Drilling works and Topographical Survey Works for the Master Plan Study on Road Slope Management in Bhutan
Name of the Client: Kokusai Kogyo Co, Ltd.
Project Description:
-To obtain direct information on the subsurface geology of the area through the works.
-To obtain information on the landslide movement and features of the areas through the works.
Scope of work:
a) Geo-technical Drilling Work (Core drilling)
Geo-technical Drilling work comprise of core drilling works in 76 mm diameter of down-the-hole hammer (DTH) method including drawing works of the geological column diagram and standard penetration test (SPT). The works aim to survey slope failure mechanism and, incentive and predisposed factors using the typical vulnerable slopes targeted in Thomang Cliff area (site1) and Nalajing (GanglaPokto) landslide area (Site 2) of Bhutan. The quantity of geo-technical drilling work is 3 boreholes (one 60m borehole and two 50m boreholes) for site 1 and 2 boreholes (two 25m boreholes) for site 2.
b) Geophysical (Seismic) Exploration Work
This work is a geophysical exploration along cross-section survey lines (4 lines namely, three 200m lines for site 1 and one 300m line for site 2). This work aims to determine three-dimensional mechanism of the slope disaster.
c) Soil Laboratory Test Works
This work is a laboratory test using the undisturbed core samples obtained by core drilling. This work aims to determine the disaster factors, assess the hydrological conditions (e.g. spring water, drainage, surface water and water seepage), and evaluate the effectiveness of the current slope disaster management measures on two typical slopes of Bhutan. The quantity of samples for the soil laboratory test is 6 samples, and when samples will be collected, another test pits which are different from the target boreholes as planned in the geo- technical drilling work shall be drilled based on the geological samples of boreholes cores.
d) Topographic Survey work
This work comprises plane survey (200m*200m for site 1 and 300m*200m for site 2) and corss-section survey (total 4 lines,200m*3 line for site 1 and 300*1 for site 2) in Thomang Cliff are and Nalajing (Gangla Pokto) landslide are of Bhutan. This work aims to determine three-dimensional topographic condition of the slope disaster site.
