ENGINEERING-GEOLOGICAL PROPERTIES OF UPPER CARBONIFEROUS
KARSTED ROCKS ON THE TERRITORY OF MOSCOW
É. Yu. Nesynova1 and A. I. Yudkevich1
Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 3, March 2006, pp. 38 – 41.
The thickness of the stratum of Jurassic clays is a criterion of sinkhole danger.
Engineering-geological prospecting and design of build-
ings and structures on the territory of Moscow necessarily in-
cludes estimation of the danger of sinkholes and internal ero-
sion of the region studied. This requirement is stipulated by a
special instruction of the Moscow Government [2]. In accor-
dance with this instruction any program of engineering-geo-
logical prospecting for a new construction site includes deep
boring (80 – 120 m) with opening of monolithic limestone to
a depth of 5 – 10 m and geophysical studies. The main task is
the determination of “karst cavities and strongly crushed
cracked and tectonic zones” [2]. The main danger in the re-
gions of karst manifestation (and its potential possibility) is
the presence of cavities in karst rocks. The instruction re-
quires their elimination by plugging or compaction of the
above-lying rocks. The erected construction “should be
checked by computation that allows for... the formation... of
a sinkhole 6 m in diameter under the building or the struc-
ture” [2]. The experience in prospecting acquired by the
“Gidroproekt” Institute in various regions of Moscow shows
that the Upper Carboniferous karsted rocks have some spe-
cial features that do not fully meet the requirements of the
active instruction.
When prospecting a region for complex development
Gigroproekt specialists have studied the geological structure
of the Zakharkovo floodplain in the valley of the Moskva
River at the west boundary of the city. A large ancient ero-
sion zone passes under the recent left-bank floodplain zone.
In the Moscow Region it is known as Central Preglacial Val-
ley [1]. A fossil saddle lies at a depth of 40 – 45 m below the
Holocene riverbed. Upper Carboniferous rocks are opened in
depression flanges to a depth of 84 – 114 m (Fig. 1). They
are represented by alternating limestone and clay strata that
are arranged in three horizons, i.e., the Dorogomilovskii,
Khamovnicheskii, and Krevyakinskii (from top to bottom).
Each horizon consists of two strata (members), i.e., a lower
carbonaceous stratum and an upper argillaceous stratum. The
section of the Zakharkovskaya floodplain consists of the Me-
shcharinskaya stratum (C3mð), the Perkhurovskaya carbona-
ceous stratum (C3pr), the combined Neverovskaya and
Voskresensk argillaceous stratum (C3nv + vs), and the Suvo-
rovskaya carbonaceous stratum (C3sv). Middle Carbonifer-
ous limestone of the Myachkovsk horizon (C2mè) lies still
lower.
Sinkholes in the carbonaceous rocks have been studied
by boring and by a set of geophysical methods that included
electrometry (the method of vertical electric probing and
seismic profiling) and the correlation method of refracted
waves. The geophysical study was performed for solving the
following problems: mapping of the boundaries of an ancient
erosion incision, determination of the position of the roof of
Jurassic clays and of their thickness, study of the trace of the
roof of the limestone stratum from the surface (the Perkhu-
rovskaya member C3pr), and determination of weakened
(karsted) regions in them.
The electrometric data made it possible to amend the
contour of an ancient erosion depression. The top boundary
of the bearing high-resistivity geoelectric horizon was used
for determining the range of occurrence of the Perkhurov-
skaya limestone in a section of the stratum. Weakened zones
primarily occurring near the flanges of the ancient incision
were singled out according to the reduced values of electrical
resistivity in the Perkhurovskaya limestone.
Results of seismic prospecting were used to determine
with sufficient accuracy the boundaries of a stratum of loose
alluvial quaternary sediments (aQ4) and of the roof of the Su-
vorovskaya limestone (C3sv) with characteristic high veloci-
ties of elastic waves (3.1 – 3.2 m/sec).
The strongly karsted state of the Perkhurovskaya lime-
stone determined by geophysical methods has been con-
firmed by boring. The Perkhurovskaya stratum was bored in
14 places. In virtually all cases the composing rocks had
traces of intense leaching that manifested itself by a macro-
pore texture and numerous caverns in the limestone. The
caverns were from 1 – 2 mm to 0.5 cm in size or even larger.
In addition to the caverns the rocks contained pockets of lime
Power Technology and Engineering Vol. 40, No. 3, 2006
148
1570-145X�06�4003-0148 © 2006 Springer Science + Business Media, Inc.
1“Gidroproekt” Institute, Moscow, Russia.
dust, clay layers, and other features of dissolution. Three
wells (21% of the total number) opened considerable (up to
5 m in size) ancient sinkholes corresponding to the total
thickness of the Perkhurovskaya stratum. The limestone has
been fully removed from them and replaced by secondary
products of karst formation or by a filler drawn from the out-
side (lime dust, clay, gravel). Cases of boring tool dropping
or of the presence of free-flowing, plastically flowing, and
Engineering-Geological Properties of Upper Carboniferous Karsted Rocks on the Territory of Moscow 149
TABLE 1
Test Soil
Parameters of properties
W
density, g�cm3
e Sr
plasticityIl
ñ ñd
ñs
WL
Wp
Ip
1Clay
0.171 2.21 1.89 2.78 0.473 1.005 0.363 0.195 0.17 – 0.14
2 0.235 1.97 1.60 2.74 0.718 0.897 0.414 0.213 0.20 0.11
Fig. 1. Geological-lithological section.
other weak rocks in the secondary filler of the voids (karst
deposits kst) have not been observed. As a rule, karst depos-
its were withdrawn in the form of normal and dense enough
drill cores. The parameters of physical properties of the clay
filler are presented in Table 1. It seems that the deposits of
kst are quite ancient and dense. For example, the clay from a
sinkhole opened by one of the wells has a compacting factor
of 1.09. Some cases in which the karst can be characterized
by marked weakening of the rocks and by the presence of
pockets of lime dust are an exception.
Limestone of the Suvorovskaya stratum (C3sv) and the
seat rocks of the Middle Carboniferous Myachikovskii hori-
zon (C2mè) are preserved somewhat better than the Perkhu-
rovskaya stratum. This can be inferred from the state of the
drill cores, from the growth in the velocity of seismic waves
(in the Suvorovskaya limestone it is 3.1 – 3.5 km/sec against
150 É. Yu. Nesynova and A. I. Yudkevich
1 2 3 4 5
6 7 8
Mosc
ow
Riv
er
Zakharkovo
village
3176400 3176600 3176800 3177000 3177200 3177400 3177600 3177800 3178000 3178200 3178400 3178600 3178800
6170800
6171000
6171200
6171400
6171600
6171800
6172000
6172200
6172400
6172600
6172800
6173000
6173200
6173400
6173600
6173800
6174000
6174200
V-1
V-2
V-3
V-4
V-5
V-6
V-7
V-8
V-9
V-10
V-11
V-12
V-13
V-14
V-15
V-16
V-17
V-18
V-19
V-20
V-21
V-22
V-23
V-24
V-25
V-26
V-27
V-28
V-30
V-31
V-32
V-33
V-34
V-35
V-36
V-37
16I
17I
11*
12*
13*
14*15*
16*17*
18* 19*
20*21*
22*
23*
25*
26*
27*
28*
29*
30*
31*
hole-1
hole-10
hole-11
hole-12
hole-13
hole-14hole-15
hole-2
hole-3
hole-4
hole-5
hole-6
hole-7
hole-8hole-9
S-1
S-10S-2
S-3
S-4
S-6S-7
S-8
S-9
S-C
S-AS-B
GP-4
TZ-3
TZ-4
1
2
3
4
5
67
8
14
20
27
28
29
30
31
32
33
34
35
43
61
62
52
70
76
TZ-1
TZ-2
TZ-3
TZ-4
TZ-5
TZ-6
TZ-7
TZ-8
TZ-9
TZ-10TZ-11
TZ-12
TZ-13
TZ-14
TZ-15
TZ-16
TZ-17
TZ-18
TZ-19
TZ-20
TZ-21
TZ-22
TZ-23
TZ-25
Fig. 2. Map of sinkhole danger: 1, drill hole; 2, probing point; 3 – 4, boundary of erosion of: 3, Jurassic deposits, 4, Perkhurovskaya limestone;
5, area of erosion of Perkhurovskaya limestone; 6 – 8, zones of sinkhole danger: 6, dangerous, 7, potentially dangerous, 8, safe.
the 2.1 – 2.6 km/sec in the Perkhurovskaya stratum), and
from the results of laboratory tests of withdrawn rock sam-
ples (Table 2). At the same time, they have traces of leaching
and regions of crushed rock. A case of dropping of a drilling
tool into a sinkhole 0.9 m high has occurred in the
Suvorovskaya limestone.
Thus, regions of strongly karsted rock have been deter-
mined on the territory of the Zakharkovskaya floodplain.
These are limestones and dolomites of the Upper Carbonifer-
ous Perkhurovskaya stratum (C3pr) lying in a 103 – 114-m
range of absolute marks; their roof is situated at a depth of
16 – 24 m from the surface. The thickness of the karsted stra-
tum reaches 6 m. The cavities formed in the stratum are
filled with secondary products; in some cases the limestone
has been fully removed due to the karst process. The distri-
bution of the karst over the area is nonuniform. According to
the data obtained by drilling and by geophysical studies the
most karsted rocks occur in the flanges of the preglacial ero-
sion valley and partially outside its boundaries over the
northern end of the recent-day floodplain. The part of the
area where the drill holes have opened filled cavities in the
Perkhurovskaya limestone and where the geophysical study
has shown the presence of numerous cavities is singled out
as a karst-dangerous territory.
According to the active standards the potential karst dan-
ger is determined by the thickness of Jurassic clays. They
serve as a protective layer that hinders vertical circulation of
the underground water and reduces the activity of karst for-
mation. When the thickness of this layer is less than 10 m (or
they are absent), the territory is assumed to be potentially
dangerous with respect to sinkholes [3].
An analysis of propagation of Jurassic clay deposits over
the territory has shown that their thickness is variable. Within
the contours of the ancient erosion incision the Jurassic clay
has fully degraded. Under the high terrace the thickness of
Jurassic clays reaches 20 m. On the Zakharkovskaya flood-
plain it fluctuates from 0.5 to 8.5 m (in the latter case we im-
ply the opened thickness of the rock). In accordance with the
active standards the part of the area characterized by low
thickness of Jurassic clays (the opened thickness is less than
7 m) is classified as potentially dangerous with respect to
sinkholes. A map of the sinkhole danger of the region is pre-
sented in Fig. 2.
It should be noted that the karst developed in the Perkhu-
rovskaya limestone is quite ancient. Judging by the confine-
ment in an ancient erosion scour, it was formed in the
preglacial period (presumably several hundreds of thousand
years ago). The formation of karst was primarily stimulated
by the special features of the paleoaccidence. The existence
of a deep erosion incision predetermined the hydrodynamic
conditions required for its development. At the present time
the process of karst formation has ended fully or to a consid-
erable degree. The cavities formed have been filled with a
clay material. Today the accidence does not promote active
circulation of underground water. A major (or at least a con-
siderable) part of the easily soluble carbonates has leached.
External features of active karst formation are absent.
The floodplain does not bear erosion pools, settled soil,
riverbed deformation, or other manifestations of karst forma-
tion. This gives us grounds to classify the karst encountered
in the section of the Zakharkovskaya floodplain as a fossil
kind (paleokarst).
The active standards do not differentiate between paleo-
karst and karst though it is obvious that the active karst and
the paleokarst present different dangers for construction. Un-
der the conditions of paleokarst occurring at a depth of 20 m
and having a thickness of not more than 3 m, formation of
sinkholes is virtually impossible. The example of the Zakhar-
kovskaya floodplain shows that the karsted limestone on a
territory classified as sinkhole-dangerous according to the
active instruction has been virtually fully substituted by sec-
ondary deposits (kst)C3
that often have high enough plastic
characteristics. Construction and design in this zone does not
require special antikarst measures, but the elevated voidage
of the limestone and of the dolomite should be taken into ac-
count by using lower strength parameters of the rocks in the
design and by thoroughly studying the properties of the filler
of sinkholes treating it as an independent engineering-geo-
logical element. In this connection it is expedient to treat the
regions with developed paleokarst as a special zone and to
develop special requirements for this zone.
REFERENCES
1. B. M. Dan’shin, The Geological Structure and the Mineral
Wealth of Moscow and Its Neighborhoods [in Russian], Mosk.
Obshch. Lyubitelei Prirody, Moscow (1947).
2. Instruction for Designing Buildings and Structures in the Regions
of Moscow Characterized by Manifestations of Karst and Inter-
nal Erosion [in Russian], Izd. Mosgorispolkom – GlavAPU –
Mosproekt-1 – Mosgorgeotrest, Moscow(1984).
3. Moscow. The Geology and the City [in Russian], Izd. IGÉ
RAN – Mosgorgeotrest, Moscow (1997).
Engineering-Geological Properties of Upper Carboniferous Karsted Rocks on the Territory of Moscow 151
TABLE 2
Stratigraphic
indexRock
Parameters of properties
Wm
Wu
ñm
, g�cm3 ñu, g�cm3 R
comp, MPa R
tens, MPa
C3pr Limestone002 005
0045
. .
.
� 004 008
005
. .
.
� 203 222
213
. .
.
� 215 231
223
. .
.
� 2 4 115
72
. .
.
� 05 21
135
. .
.
�
C3sv Dolomitized limestone003 004
0035
. .
.
� 004 005
0045
. .
.
� —
.2 46
256 258
257
. .
.
� 368 658
513
. .
.
� 31 45
38
. .
.
�