CONTENTS

J. Duhok Univ., Vol.14, No.1 (Pure and Eng. Sciences), Pp 39-51, 2011
ENGINEERING CLASSIFICATION AND INDEX PROPERTIES OF THE
ROCKS AT DERBANDI GOMASBPAN – SUGGESTED DAM SITE
MOHAMED TAHIR A. BRIFCANI
School of Engineering, Faculty of Engineering and Applied Sciences, University of Duhok, Kurdistan Region-Iraq
(Received: May 15, 2010; Accepted for publication: February 27, 2011)
ABSTRACT
This study concerns the ground conditions and the engineering properties of the rocks in Derbandi Gomasbpan
(Gomasbpan valley), which was suggested to be a site for a dam construction. The study emphasized on the
qualitative engineering classifications and index properties of the existed rocks at the site as to be the dam foundation,
their abutments and for the stability of the slopes, including the slopes of the dam embankments (when it is built
from) during and after construction.
The Pila Spi Limestone which is one of the rock types and widely exposed at the site, was exceptionally, studied
for its engineering behavior. The geotechnical laboratory testing of Pila Spi limestone was carried out and the
acquired data were used for its engineering classifications both, as an intact rock and as a rock mass. The study
results show that the general qualitative classification of this rock is rigid and high in mass strength, eventually, the
rock was reliably evaluated for the dam foundation and its abutments.
The Gercus and Kolosh Formations which are predominantly composed of shale, which extensively, exposed at the
dam site and most of the stream drainage-basin area. The rocks at the dam site were studied in part for their
mechanical properties, emphasized on their slake durability indexes and shale ratings. The test results of the slakedurability
and rating of the shale were variable in values, few tested samples showed, relatively, with very low rating.
The shale rating results were evaluated for the estimations of allowable slope angles of the dam embankment
(construct from this shale) as a function of the shale ratings. The allowable lift thicknesses and required compaction
field densities of the shale for the embankment were also estimated.
KEYWORDS: Gomasbpan, Dam Site, Rocks, Index-Properties, Shale Rating.
D
1. INTRODUCTION
erbandi Gomasbpan is located about 30
Km NE of Hawler ( Irbil) city,
between the longitudes 44 o - 18’- 00’’ and 44 o -
21’- 00”N and the latitudes 36 o - 16’- 00’’ and
N
App. Scale 1: 3,500,000
Fig. (1): Location map
36 o - 19’- 00’’ E, at the vicinity of Gomasbpan
village, Figure (1), and (2). The location was
suggested to be a site for a dam construction, so
that, the surrounding area could be developed for
the out-door people-recreations, as well as for
the agricultural and inhabitant benefits.
Suggested dam site
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