WO2005098195A1

WO2005098195A1 - Equipment and procedure of coupling socket pipe sections for trenchless laying

Info

Publication number: WO2005098195A1
Application number: PCT/CZ2005/000032
Authority: WO
Inventors: Robert CERMÁK
Original assignee: Cermák A Hrachovec A.S.
Priority date: 2004-04-08
Filing date: 2005-04-06
Publication date: 2005-10-20
Also published as: CZ295866B6; CZ2004467A3

Abstract

The procedure of coupling consists in the procedure where after excavating starting pit and operation trench drilling and successive backreaming of pilot borehole is executed with simultaneous pulling-in pipe sections when coaxial force generated by drilling rig acts simultaneously and pulls-in drilling head with pipe line into borehole and where force generated by movement of piston of hydraulic chain stretcher pushes and seals finally the pulling head connection with pipe line. Equipment consists of drilling rig (4) with pulling head (15) through top of which passes pulling hanger (13) which is provided from the inner side of pulling head (15) with suspension eye (16) which pulling chain (7) passing through all pulled-in pipe sections is connected to and which is coupled with piston (20) of hydraulic chain stretcher (8) which is supported through thrust plate (19) on socket of the last pulled-in pipe section (3).

Description

Equipment and procedure of coupling socket pipe sections for trenchless laying.

Technical field

This invention applies to the equipment and way of coupling socket pipe sections for trenchless installation of ductile iron pipe lines under earth surface for the transport of liquid media such as e.g. drinking water, rainwater, sewage water or service water and belongs to the area of underground building construction and municipal economy water management.

Background art

Pipe laying by means of the trenchless technology under roads, highways, railway banks, rivers etc. has been known in the Czech Republic since the beginning of 90th of the last century. The sections of steel pipe lines for the transport of liquid or gas media are connected together in operation trenches or on the surface by electric arc welding and are pulled-in into the starting pit by means of a drilling rig or another pulling equipment by individual sections or in total length. The pulling head or the pulling hanger is usually fixed to 1st pipe section mostly by electric welds. In case of trenchless laying of flexible piping of linear polyethylene (HDPE or LDPE) by means of horizontal directional drilling technology "HDD" the plastic pipe sections are welded together exclusively on the surface in the whole length of the pulling interval by means of a special fusion welding technique and are pulled-in by a drilling rig under the earth surface in the complete length all at once. The pulling heads of special design are provided with wedge jaws that "bite" into the inner diameter of the first plastic section. The higher is the pulling force during drawing the pipe line into the borehole under the earth surface the stronger is the "bite" of the pulling head jaws. It occurs sometimes that the jaws cannot hold the tension and the pulling head pulls out from 1^st section and the whole pipe line may freeze in the borehole in the middle of its way. Other "Cracking" and "Burst Lining" trenchless technologies represent destructive methods of the exchange and reconstruction of old pipe lines where pulling force of the winches, breaking tools and pneumatic hammers is applied. Rigid pulling equipment having installed pulling force of 400 to 600 kN are used for pulling-in linear polyethylene, polypropylene or PVC into the old pipe lines. Pipe sections are connected on the surface by means of fusion welding and the first section is fixed to the expander or breaking device with clamping securing bolts which 1^st pipe line section is screwed through. In the German patent No.DE 19608056 Cl the Cracking/Bursting equipment for replacement of old pipelines by short plastic pipes especially designated for transport of sewage and rain water is described. The equipment consisting of a tool for drilling or breaking old pipelines and pulling-in simultaneously of pin ends of single pipes into box ends of previous pipe sections consisting of a vertical stretching beam with a stretching equipment being connected with a single continuous piece of chain which is connected on its opposite side with a pulling equipment or with a tool for breaking old pipes. Whole completed pipeline has got corresponding outside and inside diameters i.e.are flush jointed. This new plastic pipeline is not determinated for transport of drinking water, the coaxial alignment of short plastic pipes can't be priority of the pullback process which is on the other hand a vital condition for securing tightness coupling of socket pipe sections made of ductile iron. In case of the horizontal "Ramming" trenchless technology the thick wall steel pipe section is driven by percussion technique into the soil which is removed from the heading by means of an helical auger located inside the piping. The pipe sections are extended in the operation trench/shaft by electric welding. Pipe sections made of stoneware, basalt or concrete intended for sewage conduits, drainage of slopes, railway embankments, drainage water collectors etc. are installed under earth surface by applying steered and unsteered Soltau, Geisert, Herrenknecht etc. microtunnelling techniques. The principle of these technologies consists in jacking the pipe sections beliind the drilling head which is controlled hydraulic ally. Drilled soil in the quantity of up to several tens of m³ is transported to the surface and should be taken away outside the working site. Inflexible pipe sections made of ductile iron which have been nowadays used for water mains, gravity sewer systems etc. are pipes of French provenience, type Pont-A- Mousson with Standard sockets. Coupling of pipe sections, i.e. sliding the spigot into the socket of the previous pipe should be carried out with perfectly axially aligned pipes. Angular deviation, so called "axial deflection" of the pipe is allowed only after finishing the assembly of the joint. The permitted angular deviation of individual pipe sections is 1.5° - 5° according to the diameter of the pipe, radius of bend in the permitted angular deviation is 100 m. Fixed but not undisengageable coupling of the pipe socket end by the Ni lock is provided by metal jaws of wedge shape located inside trie sealing ring which, after assembling the pipe sections will bite into the spigot of the following pipe. Sealing of the spigot- and-socket joint is achieved by means of the ("O") sealing ring made of special rubber. For the laying of ductile iron piping when applying classical method, which is nowadays a current way of laying, a trench is usually made in the earth into the depth of 2 to 3 m and 0.5 to 0.7 m width, which depends on the diameter of the pipe and on the required operation space on the trench bottom. Length of the excavated trench depends on the surface situation. For the safety's sake the trench must be secured with horizontal sheeting along the whole excavated length. In the town development, with respect to the surface traffic the whole length of the pipeline must be divided into several trench intervals which will be backfilled after laying the pipes and then the work continues in next sections. In all cases one should dig few tens of cubic meters of soil which is situated beside the trench outside the operation space. The excavated soil should be mostly transported out of the working site due to limited occupation of the operation area on the surface. Individual sections of the piping are buried in the trench by means of a crane or hydraulic lorry loader and juta purchase clamps. The trench bottom must be levelled according to the grade line and should be lined with sand or fine rock chips. The sand sub-base of 20 cm thickness approximately must be compacted before laying the pipes. In the trench the spigots of the pipe sections are jacked into the sockets manually by means of levers or with the aid of the excavator bucket. The pipe interval assembled in this way should be aligned into the required direction by means of laser or levelling instrument. In accordance with the requirement of the project the tightness of the pipe socket joints of the complete interval of the pipe line should be checked by inner pressure test still before backfilling of excavations. Both ends of the pipe line, i.e. the first spigot and the socket of the last pipe line should be surveyed. Only then the pipe interval can be covered with delivered backfilling material, not with excavated soil and then the assembly of the next pipe interval can be started. Backfilling material must comply with the respective civil engineering standards. Testing of the backfill and of sufficient compaction of the pipe line underbed and overlying bed should be carried out. Final pressure test of the pipeline interval sealing by means of overpressure is carried out at the end. It occurs that thus assembled and laid pipe sections do not comply with pressure test condition and the pipe interval should be re-sealed again. From the practical point of view this procedure is financially demanding and time consuming. Moreover the pipe laying from the surface limits the road traffic as well as the movement of the pedestrians on the pavements, regardless of ecological burden upon the environment during excavation works and transport of soil. It can usually happen and one cannot succeed to level the trench bottom into the required grade arid for this reason it is necessary to carry out subsequent levelling of the underbed along the complete length of the pipe interval, which results in longer operation periods needed for laying the pipe line. During laying the pipe interval a crane, lorry loader, compacting machine, excavator/loader, a lorry and operators of these means must be always present for the whole time, which increases excessively the running costs of the job site. To eliminate or at least to minimize all these disadvantages the invention offers such a solution which helps to eliminate above all the ecological burden of the life environment caused by excavation works, concentration of earth working machinery and disadvantages of deviations of individual pipe sections from the axis of the pipe line and elimination of all problems connected with the tightness of the pipe interval.

Summary of the invention

All above mentioned disadvantages can be eliminated by applying the method of coupling socket pipe sections for trenchless laying in accordance with this invention ^■which consists in the principle that after digging the starting pit and operation trench, drilling and backreaming of the pilot borehole are carried out with simultaneous pulling- in of the pipe sections where axial force of the drilling rig which tows the pulling head -with the pipe line into borehole acts simultaneously with the force applying final pushing and tight connection of the pulling head and of all separate pipe sections which is generated by the movement of the piston of the hydraulic chain stretcher. Each pipe section , during the assembly and pulling- in into the borehole is placed into an U-beam which is laid on the bottom of the operation trench. During backreaming the pilot hole and simultaneous pulling-in of the pipe sections into the borehole a polymer causing temporary bonding of drilled soil and its replacing and squeezing into the walls of the borehole is added into the drilling fluid. The equipment for coupling socket pipe sections for trenchless installation and pulling-in of the pipe line consisting of a drilling rig, drill pipe string, compaction fluted backreamer and a swivel which is connected with the pulling head through a pulling hanger consists, according to this invention in that, that the pulling head is firmly connected with the pulling intermediate pipe , the pulling hanger which is provided with a suspension eye from the inner side of the pulling head which the pulling chain is connected to, passes through the top of the pulling head. The pulling intermediate pipe is provided with two holes for insertion of the pulling pin passing simultaneously through the walls of the spigot of the first pipe section. The pulling chain passing through all drawn pipe sections is connected through a set of pulleys one of which being connected with the piston of the hydraulic chain stretcher,, the pulling chain stretcher being braced through a thrust plate on the socket of the last pulled-in pipe section. The pulling hanger is provided with. a conical supporting plate of the same taper ratio as of the pulling head on which the thrust plate is supported. Furthermore the equipment is completed with a U-beam for securing the alignment of pipe sections which is buried on the bottom of the operation trench and is fixed on supporting wooden prisms in the direction and slope of the pulled-in pipe line.

The merits of the trenchless laying of the piping of ductile iron consist generally in the installation of the piping under the earth surface without trenches, limitation of the traffic on the communications and on the pavements and in minimum, requirements on the occupation of the working area. These advantages will come to the fore especially when laying the water mains in the town development. For this reason a drilling rig intended for use and equipped for horizontal directional drilling is utilized here. The starting pit and the target operation trench are dug in advance only. The drilling rig drills first the pilot borehole from the surface in the axis of the projected pipe line between the starting pit and the target operation trench. Steering and location of the pilot drilling head ("mole") are controlled using a DigiTrak^R Eclipse™ iGPS™ (inGround Positioning System), Subsite^R 750 Tracker navigation systems or are performed by other equivalent navigation systems. Navigation systems for pilot drilling heads consist of a transmitting probe which is inserted into the string of drill pipes behind the pilot drilling head. Low-frequency waves on the route of the pilot borehole are intercepted by a worker ("trackman") by means of the above mentioned receiver and on the LCD display which makes part of the receiver the pitch and roll and depth of the pilot drilling head under the ground surface and other necessary data on the trajectory of the pilot hole are displayed in the form of digital targets or icons. These data are transmitted by the remote signal to the display of the drilling rig operator who is informed in this way about the position of the pilot drilling head which may be even in the distance of several hundred meters from the drilling rig. In addition to this the operator and the trackman are equipped with a "hawky-talkzy" SWT (Short Wave Transmitter) transmitter which the trackman uses for giving instructions to the drilling rig operator to change the position of the pilot drilling head. The pilot drilling head will crawl to the surface near the bottom of the target operation trench situated in tJhe distance of several tens to hundreds of meters from the starting pit where the pilot drilling head is disassembled and the compaction fluted backreamer is mounted on. By means of back pulling and rotating the drill pipe string and compaction fluted backreamer the pilot borehole being flushed with mud fluid - polymerized fluid is recommended -is finally backreamed to greatest diameter and gradually the whole interval of the pipe line is pulled-in into thus formed borehole along the complete projected length. Pulling-in of the piping is terminated in the starting pit in the vicinity of the drilling rig where the assembly of junction points of the fittings, branch pipes, inverted siphons, valves etc. will be executed. The pipe sections are assembled in successive steps inside a single operation trench at the end of the pipe line. Pulling-in of the pipe line is executed completely "invisibly" for the human eye under the ground. During pulling-in the axial force of the drilling rig acts simultaneously and pulls-in the pulling head with the pipe line through the borehole in direction towards the starting pit as well as the force generated by the movement of the piston of the hydraulic chain stretcher causing final pushing and tight connection of the pulling head and of all individual pipe sections. This force pushes the chain stretcher onto the socket of the last pipe section through the pulling chain. Attraction of this technology consists above all in price relations. The described technology of laying the ductile iron piping may represent up to 50% of the costs in comparison with the classical method of installation the piping into surface trenches. Also times of coupling the sections and of pulling-in the pipeline of ductile iron may represent a few hours only in comparison v^ith the several days to weeks lasting classical methods of surface installation. These times can be achieved, apart from other things, even thanks to the unique design of the pulling head, pulling hanger, pulling intermediate pipe and suspension of the pulling chain as well as to the effective coupling of individual sections in the U-beam by means of the chain stretcher. The socket pipe sections are drawn in direction towards the drilling rig i.e. "along the hair" (spigot towards the drilling rig), which completely eliminates blocking of the sockets in the walls of the borehole. During backreaming and pulling-in of the pipe line, replacing and squeezing of a substantial quantity of soil into the walls of the borehole occurs. This compacted volume of soil will be loosened in the course of time due to temporary bonding effect of the liquid solution of anion polymers of Argipol trade name and due to earth moisture and will fill uniformly the space between the pipe sections and diameter of the borehole in the form of semisolid clay-sandy paste. Thus the original geostatical conditions in the neighbourhood of the pipe line will be restored. This is a very important moment for securing safety of the earth surface against soil settlement and subsidence along the route of the projected pipe line. Trench backfilling and problem of additional compacting of the sub-fcase and overlying rock of the pipe line do not take place completely as it is usual in case of classical installation of the pipe line from he surface. This technology and technique of coupling the sections can be applied above all for straight pipe lines of ductile iron of DN 60 to 300 diameters according to the purpose of the piping system. Pipe line of ductile iron can be pulled-in even in bends of about 100 m radius of pipe line bending. The length of the pulled-in piping section is given by the project and is rewarding economically already with length over 30 meters but may pay even over 100 m. The installed pulling capacity of the drilling rig should be adapted to these lengths. The advantage of this method and equipment according to this invention consists in quick and accurate coupling of piping sections of ductile iron in operation trenches. Accurate laying of the pipe line in the direction and slope is provided by tension of the pipe line in coaxial position of individual pipe sections. Pulling-in the pipe line is secured both against breakage and against loss of the pipe line in the borehole caused by the pulling chain. Trenchless laying of the ductile iron piping without surface trenches, excavations of soil and occupations of large areas on the surface maintains original geostatical conditions in the vicinity of the pipe line without backfilling and additional compacting of the overlying rock, thus eliminating the danger of surface soil settlement on the route.

Brief description of drawings

All enclosed Figures represent the technique and technology of execution of trenchless laying of ductile iron piping, handling with individual pipe sections, details of coupling the pipe sections etc. schematically only. Figure 1 represents schematically a general course of pulling-in ductile iron piping under the earth surface. Figure 2 represents 1^st and 2^nd pipe sections laid on a steel U-beam on the bottom of the operation trench. Pulling chain which is fixed to the chain stretcher on one end and in the suspension eye of he pulling hanger on the other end passes through all pipe sections. Figure 3 illustrates the pulling head in connection with 1^st pipe section. Figure 4 represents the coupling of the socket and spigot of ductile iron pipe sections and their interconnection with the pulling chain. Figure 5 is an illustration of the chain stretcher situated on the socket end of the last pipe section. In this Figure the way of pushing the spigot of the pipe section into the socket of the previous pipe section is evident.

Examples of execution of the invention

The equipment for coupling sock et pipe sections for trenchless laying consists of a drilling rig 4, string of drill pipes 5, compaction fluted backreamer 10 and swivel 11 which is connected with pulling head ,15 through pulling hanger JA Pulling head 15_. is connected firmly with pulling intermediate pipe 9, where through top of pulling head 15 passes pulling hanger 13 which, from inner side of pulling head 15 is provided with suspension eye 16 to which pulling chain 7 is connected to. Pulling intermediate pipe 9 is provided with two openings for inserting pulling pin 12 passing simultaneously through the walls of the spigot of 1^st pipe section 3. Pulling chain 7 passing through all pulled-in pipe sections is connected through a set of pulleys one of which is connected with piston 20 of hydraulic chain stretcher 8. Hydraulic chain stretcher 8 is supported through thrust plate 19 on the socket of the last pulled-in pipe section 3. Pulling hanger 13. is provided with supporting plate 14 of the same taper ratio as pulling head L5_ which supporting plate 14 is supp rted on. Further-more the equipment is completed with U-beam 6 for securing the axial alignment of pipe sections which is situated on ttie bottom of the operation trench 1 on wooden suspension prisms 18 in direction and slope of the pulled-in pipe line. This equipment is illustrated in Figures 1 to 5.

Figure 1 illustrates practically the course of backreaming of pilot hole and simultaneous pulling-in of pipe sections 3 from operation trench I into starting pit 2 in direction towards drilling rig 4. Drilling rig 4, by -means of drilling string which consists of drill pipe string 5 and compaction fluted backreamer 10 which backreams pilot hole and which pulls back individual pipe sections 3 into borehole 17 step by step. Pipe line consisting of pipe sections 3 from which the first pipe section is firmly connected with pulling pin 12 with pulling intermediate pipe 9 which is firmly connected with pulling head L5 is pulled by means of pulling intermediate pipe 9 and pulling chain 7 in the interval of operation trench 1 and starting pit 2 in vhich the ends of the first and the last pipe section 3 will be provided with fittings and ttie whole interval of the pulled-in pipe line is checked at the end by pressure test for tightness of socket coupling. As described above the pilot drilling head crawls up in operation trench I namely at its bottom. Pilot drilling head is dismantled and instead of it compaction fluted backreamer 10 is screwed on the end of drill pipe string 5. Figure 2 illustrates the position of drill pipe string 5, compaction fluted backreamer 10. pulling equipment consisting of swivel 11, pulling head 15 with pulling intermediate pipe 9, pulling pin 12_ and then continue 1^st pipe section 3 and 2^nd pipe section 3_. positioned in U-beam 6 on wooden suspension prisms !8_ in operation trench 1. Inside pipe sections 3 passes through pulling chain 7 one end of which is firmly fixed in suspension eye 16 of pulling head 15_ and the second end is fixed in chain stretcher 8. Individual sections of pulling chain 7 are connected by means of chain shackles. Pipe sections 3 of ductile cast iron are located in the neighbourhood of operation trench 1. All pipe sections 3 are laid into the trench with their spigots in direction towards the drilling rig. Each pipe section before fcr ing into the trench is pulled through on the surface with pulling chain 7 of length exceeding by about 1 to 2 m the length of pipe section 3^ As evident from Figure 3, smooth end of 1^st pipe section 3 is secured in pulling intermediate pipe 9 with pulling pin 12 against pull out. Pulling intermediate pipe 9 is firmly connected with pulling head 15 of conical shape the purpose of which is to protect the pipe line against penetration of drilling fluid and other impurities into the piping. Figure 3 illustrates in addition swivel ϋ which is connected in direction towards drilling rig 4 to conical backreamer 0 and eliminates rotation of pipe sections 3 during backreaming and pulling-in of coupled pipe sections 3 into borehole 17. Swivel JJ, is connected by means of shackle with pulling hanger 13 passing through top of pulling head L5. On the other side of pulling hanger 13 under top of pulling head 15 inside pulling intermediate pipe 9 is situated suspension eye 16 which pulling chain 7 is suspended on. Pulling hanger 13 is provided with supporting plate JL4 which serves for supporting pulling hanger 3 on top of pulling head JA 1^st pipe section 3 is secured in pulling intermediate pipe 9 by pulling pin Y This is provided on one end with hexagonal countersink head and passes diametrically through wall of pulling intermediate pipe 9 through spigot of 1^st pipe section 3 and is screwed in wall of pulling intermediate pipe 9 on opposite end. After pulling-in 1^st pipe section into backreamed borehole 17 the next pipe section 3 is lowered into operation trench 1 the former being provided with another section of pulling chain 7 and is laid on bottom of operation trench 1 into U-beam 6 of necessary dimension corresponding to diameter of pipe sections 3,, Packing ring with Ni lock is put into socket of laid pipe section 3 and only then both sections of pulling chain 7 are firmly connected with chain shackles. Figure No. 4 represents coupling of socket and spigot of pipe sections 3 of ductile iron and following pulling-in of coupled sections into borehole Y In the left part of Figure 4 there is pipe section 3 which was already pulled-in into borehole 17. Socket end of this pipe section is located in U-beam 6 which is fixed on wooden suspension prisms 18 . U-beam 6 serves during assembling individual pipe sections for accurate coupling and axial alignment of both pipe sections 3 into required direction and slope of pulled-in pipe line. This is another characteristic element of the invention. On the right side of Figure 4 another pipe section 3 is positioned in U-beam 6. Both pipe sections are pulled through with pulling chain 7 which is connected by means of chain shackle of "hammerlock" type. Pipe section are coupled by means of thrust of chain stretcher 8 onto socket of right pipe section. Thrust plate 19 and chain stretcher 8 are sat over socket end of coupled pipe section 3. End of pulling chain 7 is pulled through a set of pulleys and is fastened in the last pulley connected firmly with hydraulic piston 20 of chain stretcher 8 and applied tension of pulling chain 7 presses spigot of pipe section 3 into socket of previous pipe section 3 up to the mark. In this position the place of sealing ring is checked and jaws of Ni lock bite into smooth end of pipe section 3. Assembly of pipe sections 3_coupled in this way is pulled-in into borehole 17 in direction towards drilling rig 4. Socket of the last pipe section 3 "runs" in U-beam 6 and in this way axial alignment of individual pipe sections one to each other is secured. In the same way the installation of the next pipe sections 3 can be proceeded_Λ Figure 5 represents a scheme of chain stretcher 8 situated on socket end of pipe section 3_, In this Figure the way of pushing smooth end of pipe section 3 into socket of previous pipe section 3 is evident. Conpled pipe section 3 is positioned in U-beam 6. Position 19 shows thrust plate whic-h hydraulically controlled chain stretcher 8 is supported on. Position 21 illustrates point of hydraulic hoses coimection. By the movement of piston 20 of hydraulic chain stretcher 8 upwards, pulling chain 7 through a system of chain pulleys is pulled out of pipe sections and produces pressure of chain stretcher 8 on thrust plate 19 and on socket of assembled pipe section 3. This causes a movement of pipe section 3 towards drilling rig 4 and tight coupling of both pipe sections.

1^st pipe section of the pipe line is situated in pulling intermediate pipe 9. Pulling pin 12 locks 1^st pipe section against pulling out from pulling intermediate pipe 9. Moreover the integrity of pipe line assembled of pipe sections 3 is provided by pullmg chain 7 passing inside through all pipe sections 3 from suspension eye 16 of pullmg hanger 13 up to chain stretcher 8 installed on socket of the last pipe section 3. This safeguard of pulled pipe line eliminates practically completely any uncoupling of pipe sections or their loss in the borehole. Axial force which is produced by the drilling rig 4 during pulling-in pipe sections 3 is distributed into pulling tension of pulling pin 12 and into pressure from chain stretcher j| on socket of last pipe section 3 produced by tension of pulling chain 7 in ratio 1:1 approximately. Pipe line assembled from pipe sections 3 is pulled-in in this way up to starting pit 2 where it is provided with connecting and distribution fittings. Pulling chain 7 is pulled out at the end from pipe line in its whole length. Pipe line is pressure tested for tightness of socket coupling and then it is handed over to the user.

Industrial exploitation of the invention

Coupling of socket pipe sections for trenchless laying of piping of ductile iron can be utilized everywhere where there are problems with occupation of areas for building activity, e.g. in town development with, dense car and tram traffic and where there are high requirements upon minimum dust nuisance and ecology of life environment e.g. in urban settlement complexes, in the neighbourhood of shopping centres, etc. By applying this technology it is possible to install pipe lines for municipal purposes, above all for transporting drinking and service water. Pipe lines of ductile iron can be laid even as gravity sewer systems of long service life. Pipe lines of ductile iron are generally preferred to plastic or steel piping nowadays for supplying the population with drinking water. E.g. Waterworks and Sewer Plants in the respective region of our republic may become one of the leading operating owners of these piping networks.

Claims

C L A I M S

1. Procedure of coupling socket pipe sections for trenchless laying characterized by the procedure when after digging the starting pit and operation trench, drilling operation is carried out and then backreaming of the pilot borehole with simultaneous pulling back pipe sections where axial force generated by the drilling rig is applied simultaneously and pulls-in the pulling head with the pipe line into the borehole and force generated by the movement of the piston of the hydraulic chain stretcher finally pushes and tightens the connection of the pulling head with the pipe line.

2. Procedure according to claim 1 characterized by positioning each last pipe section during assembly and pulling-in into the borehole on the U-beam laid on the bottom of the operation trench.

3. Procedure according to claims 1 and 2 characterized by adding polymer into borehole fluid causing temporary bonding of drilled soil and its squeezing into the walls of the borehole during the course of its simultaneous backreaming and pulling-in pipe sections.

4. Equipment for execution of trenchless laying and coupling socket pipe sections during pulback the pipe section according to claims 1 to 3 consisting of a drilling rig, drill pipe string, compaction fluted backreamer and swivel which is connected with the pulling head through the pulling hanger characterized by firm connection of pulling head (15) with pulling intermediate pipe (9) where through top of pulling head (15) passes pulling hanger (13) which is, from the inner side of pulling head (15) provided with suspension eye (16) which pulling chain (7) is connected to, where pulling intermediate pipe (9) is provided with two holes for inserting pulling pin (12) passing simultaneously through the walls of he spigot of the first pipe section (3), where pulling chain (7) passing through all pipe sections is connected through a system of pulleys one of which is connected with hydraulic piston (20) of hydraulic chain stretcher (8) , where chain stretcher (8) is supported through thrust plate (19) on the socket of the last pulled-in pipe section (3).

5. Equipment according to claim 4 where pulling hanger (13) is provided with conical supporting plate (14) of the same taper ratio as of pulling head (15) which supporting plate (14) is supported on. Equipment according to claims 4 and 5 characterized by addition of U-beam (6) for securing axial alignment of sections which is located on bottom of operation trench (1) on supporting wooden prisms (18) in direction- and slope of pulled-in pipe line.