S E M I N A R ON M O D E R N M E T H O D S OF U N D E R G R O U N D

C O N S T R U C T I O N A N D P R O S P E C T S F O R T H E I R

U S E IN L E N I N G R A D

R. M. Narbut UDC 711.8(24)061.3

The f i r s t s e m i n a r on p r o b l e m s re la t ing to the intensif icat ion of the cons t ruc t ion of underground s t r u c - tu res in c i t ies , convoked by the Leningrad Branch of the Scient i f ic-Technical Society of the Construct ion Indust ry and the Commiss ion on Foundation Engineering of the Executive Commit tee of the Leningrad Town Soviet, was held in J anua ry 1973 in the c i ty of Leningrad. The Seminar was attended by ove r 200 spec ia l i s t s f r o m 67 design, s c i e n t i f i c - r e s e a r c h , educational, and construct ion organiza t ions of Moscow, Kiev, Dnepro- pe t rovsk , Tallin, Riga, and o ther c i t ies of the USSR.

A su rvey on the cons t ruc t ion of underground s t r u c t u r e s in this country and abroad by the "wall in soi l" method was given in the pape r s p re sen ted by w o r k e r s f r o m the \rNIIGS (E. M. Pe r l e i , P. P. Sorokin, and S. P. Shik). In these p a p e r s it is shown that the above-ment ioned method can reduce the cons t ruc t ion cos t s by a f ac to r of 1.5-2 and the l abor consumption by a f ac to r of 2-3, in compar i son with the d rop - sha f t method.

The pape r s p resen ted by I. V. Gusev, V. V. Dlougii, and L I. Khanovich (VNIIGS) and by E. M0 Kol ' t sov (Gidrospets fundament-s t ro i ) desc r ibe the mach inesand equipment used for cons t ruc t ing underground s t r u c - t u re s by the above-ment ioned method. The authors also d i scussed the causes prevent ing the quick in t ro - duction of this p r o m i s i n g method, one of which is the l ack of equipment fo r digging deep t renches under d i f ferent geologic condit ions. This indicates the need fo r developing and adopting new improved types of equipment.

Several pape r s , by E. M. Kol ' t sov (Gidrospetsfundament-s t ro i ) , V. D. Ivanov (Scient i f ic-Research Ins t i - tute fo r Foundations), Vo M. Kostin (Mosstroi), ~. G. Godes, and G. F. Ol ' shevski i (LO Gidrospetsfunda- men t - s t ro i ) , were devoted to the i m p r o v e m e n t of the d rop - sha f t method, and, in pa r t i cu la r , to the e l imina- tion of i ts main def ic iency - the l a rge weight of the lowered p a r t of the s t ruc tu re - in o r d e r to reduce the soil r e s i s t a n c e b y combining di f ferent cons t ruc t ion methods. As a resu l t , i t s e e m s poss ib le to sink r e a d y - made, thin-walled sect ions o r to cons t ruc t shaf ts with shee t -p i le wails .

Exper ience with the construct ion of waterproof ing e lements fo r underground s t ruc tu r e s by using mod- e rn po lymer m e m b r a n e linings was communica ted by delegates f r o m the G1avleningradinzhstroi (V. A° Kim and M. Ya. Khazanov), where methods have been developed for the industr ia l p repa ra t ion of linings made f r o m polyethylene ro l l s by cutt ing and gluing the m e m b r a n e s by means of a Pi lad instal lat ion. Ex- tens ive work has been c a r r i e d out a t the Inst i tute in o r d e r to improve the impe rmeab i l i t y of concre te and sho te re te in underground s t r u c t u r e s by adding a eomolex a i r - en t r a in ing admixture .

P r o b I e m s re la t ing to the pro tec t ion of aboveground s t ruc tu re s agains t poss ib le deformat ions caused by underground cons t ruc t ion opera t ions were d i scussed in the pape r s p resen ted by R. A. Muller (VNIMI) and V. F. Podakov (VNIIG).

Different ideas about the locat ion of urban fac i l i t i es in underground spaces were expounded in the p a p e r s p re sen ted by M. Vo Mozalevskaya (Glavleningradstroi) , N. I. P i i r (Lenproekt), and B. G. Ustinov (Giproteatr) .

The p rob l em of the cons t ruc t ion of underwater t ranspor ta t ion tunnels in Leningrad was t rea ted in the pape r p resen ted by A. A. Bogorodetski i (LIIZhT), who examined the exper ience with the const ruct ion of an

VVITKU~ Leningrad. T r a n s l a t e d f r o m Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, p. 45, May- June, 1973.

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underwater transportation tunnel under the Morsk canal, by dropping ready-made sections, on the basis of design prepared by the Lenmetroproekt and the Leningrad Branch of the Special Design Bureau of the Glav- mosstroi, with the participation of the Ler~morniiproekt, the VNItMI, and other organizations.

The paper presented by Ya. D. Leibman (Lenmetroproekt) dealt with another urban transportation problem, namely the technical-economic convenience of the construction of a subway at a small depth in Leningrad, and with the difficulties which the designers would encounter in connection with the solution of this problem.

The resolutions of the Seminar give recommendations for further expansion of the work in the under- ground space af the city, and for the development of an integrated plan which will coordinate the construction projects for aboveground and underground structures in order to eliminate the costs involved in the r e - design and re-equipping of the underground communication systems. It was proposed to create, at the Len- ingrad Branch of the Scientific-Technical Society of the Construction Industry, a Committee on Urban Under- ground Construction, which, together with the Leningrad Branch of the Union of Architects, will be in charge of fur ther coordination of the efforts of different organizations in connection with the development of the underground space of the city. In the recommendations considerable attention was focused on the propaganda in favor of the latest construction methods and wide familiarization of the industrial organizations with the experience acquired by the leading construction trusts which have introduced new construction techniques in the underground space.

The participants at the Seminar had the opportunity to see a film showing the installation of a drop shaft in a thixotropic jacket, and to visit the projects being constructed by the Gidrospetsfundament-stroi.

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