3137
Geotechnical problems related to the development of territories in the conditions
of the Republic of Tajikistan
Problèmes géotechniques lies au développement de territoires dans les conditions de la
République du Tadjikistan
Usmanov R.A., Saidov R.S.
Geotechnical society of Tajikistan, Dushanbe, Republic of Tajikistan
Mangushev R.A.
Saint-Petersburg state architectural and construction university, Saint-Petersburg, Russia
ABSTRACT: in this paper features of construction of buildings and constructions in difficult engineering-geological conditions of the
Republic of Tajikistan are presented. Methods of design and construction of the bases and other foundations on loess collapsing soils,
on weak water-saturated soil, and prospects of development of the hilly territories needing a difficult relief are considered.
RÉSUMÉ : Il est question dans cet article de la construction de bâtiments et de constructions dans des conditions difficiles à la fois
d’ingénierie et de géologie rencontrées en république du Tadjikistan. On évoque les méthodes de calcul et de réalisation des radiers et
autres fondations sur les sols lœssiques, sur les sols peu résistants saturés d'eau, ainsi que les perspectives de développement des
territoires en terrains très accidentés nécessitant de difficiles reprises en sous-oeuvre.
KEYWORDS: loess collapsing soils, weak water-saturated soils, hilly territories, static and seismic influences.
1 INTRODUCTION
In the Republic of Tajikistan more than 90% of the territory
are presented by a mountains, and the areas of plains are made
by only 7%. The basis of development of a national economy of
the republic is made by the agrarian sector which is based on
irrigated agriculture under which about 70% of all flat territories
are allocated. The deficiency of the earth being the main reserve
for development of agricultural production, housing, industrial,
etc. types of construction always represented a special problem
and demands very reasonable and careful use.
Development of the country and growth of the population
demands increase in volumes of agricultural production and
construction of buildings of different function. Therefore,
preservation and increase in land fund put before designers and
builders of adoption of effective decisions. In this direction the
most effective are:
- substantial increase of number of stores of buildings and
constructions erected in flat territories that will allow to keep
and free territories for development of agricultural production;
- development under construction of buildings and
constructions of foothill (hilly) territories.
It should be noted that in the Republic of Tajikistan
construction of buildings and constructions is carried out,
generally in territories presented by loess collapsing and weak
water-saturated soil, and in recent years as well on foothill
(hilly) sites. Practically all territory of the republic is
characterized by 8-9 mark seismic intensity. In the specified
conditions design, construction and reliable operation of
buildings and constructions is closely connected with use of
effective methods of preparation of the artificial bases and
devices of the foundations. Taking into account it in the
republic the complex researches which results are generalized in
considered article were conducted.
1.1
Construction on the loess collapsing soils
About 70% of flat territories of the republic are everywhere
presented by loess collapsing soil which capacity changes from
5 to 300 m, and their thickness makes H
sl
= 5…30 m, exceeds
30 m less often. More than 2/3 territories of the country are put
by loess collapsing soil II of type, with the size of expected sag
from a coefficient of relative collapsing
ε
sl
= 30…150 cm.
The majority of the cities, objects of civil and industrial
function are erected in these territories. Thus till 80 years of the
twentieth century, 4-6 floor buildings therefore for practical use
researches were conducted were generally erected and the
following superficial methods of consolidation of soil, the
device of the bases and foundations (fig. 1) are
developed(Musaelyan A.A. 1982, Krutov V. I. 1982, Galitsky
V.G. and Popsuyenko I.K. 1985, Ruziyev A.R. and Usmanov R.
A. 1991):
a) Consolidation by heavy tampers weighing 50…200 kN in
combination with constructive and water protective measures.
Advantages – simplicity and use of the simple equipment, rather
low cost. Shortcomings – fast wear of the mechanisms, limited
application in the conditions of dense building.
b) The device of the condensed soil pillows 3-5 m thick and
more from a clay material in combination with constructive and
water protective measures. Advantages – simplicity and use of
the simple equipment, possibility of application in the
conditions of dense building, rather low cost. Shortcomings –
seasonality of work, big labor expenses when finishing soil to
optimum humidity, increase in terms of construction at increase
of thickness of a pillow.
c) Consolidation by energy of underwater explosions in
combination with constructive and water protective measures.
Advantages – simplicity and use of the simple equipment, low
cost. Shortcomings – limited application in the conditions of
dense building.
d) The device of the bases in tamping ditches with creation
in their basis of broadenings from rigid materials. Advantages –
use of the simple equipment, combination of processes of the
device of a ditch and consolidation of collapsing soil, the
minimum use of a timbering, decrease in reinforcing of the base
to 50% and more, low cost. Shortcomings – fast wear of the
mechanisms, limited application in the conditions of dense
building.
