RCC JACKING PIPE

·         Pipe jacking is the oldest method of trench reduction technology.

·         Powerful pipes are pushed to the ground behind the shield using powerful shields.

·         simultaneous excavation was under the shield.

·         That process is continued until the pipe line is completed.

·         Due to the excavation of the tunnel, this method provides a flexible, structured, waterproof, ready pipeline.

·         trust the wall is provided for the reaction of the jacks.

BRIEF  HISTORY

•             First mentioned in 1990, USA  by Richardson & Mayo .

•             In 1960 s , used in UK and APJA ( American Pipe Jacking Association  ) is formed .

•             In 1970 s , process is industrialized in JAPAN.

•             In 1980 s , developed in Europe .

                                (i) 1800 mm Dia trench less pipe is laid for 460 m in London 1982.

                               (ii) 560 m in water bearing  sand and graval , byels , 1983.

•             Komostu  introduced first fully automated machine  in 1975 - IRONMOL .

•             Today, pipe jacking runs remotely.

INDIAN HISTORY

•             First project is 3.5 Km in 1998, Mumbai.

•             In Cuttack 10 Km is constructed for sewer using trench less method.

•             other projects of less than 8 Km is completed in Goa , Hyderabad ,Kolkata , Delhi , Assam                   etc.

•             A total  of around 100  Km in build so far using trench less method so far.

ONGOING PROJECTS

•             55.1 Km  of interceptor sewer along  3 major drains for  reduction of pollution in Yamuna at                                                     New Delhi.

   SPECIFIC FEATURES

•             simple cyclic procedure.

•             utilized thrust from hydraulic jacks to force the pipe forward

•             person have to enter  in the pipe excavation

•             excavation can be operate manual or by machine

•             practically limit to Dia . greater than or equal to 1075 mm

•             pipe installation process occurs from front entryway and exit shaft.

 JACKING PIPE FORCED

•             forced on the jacking pipe  includes :

                                 (i) pipe dead weight

                                (ii) penetration resistance or face pressure

                                (iii) soil pipe friction

•             other forces likes :

                                (i) curvature forces

                                (ii) soil dead load .

                               (iii)railway or highway live load

•             jacking force  must  not exceed allowable pipe compression strength.

 Application

•             max diameter pipe ( 1050 mm and up ).

•             lengths can range from 30 to over 200 m.

•             sewer and drainage construction.

•             gas and water mains .

•             oil pipelines .

•             industrial pipelines .

•             telecommunication.

•             pedestrian subway ( access tunnels).

EQUIPMENT AND COMPONENT

•             JACKING PIT      

•             JACK

•             PIPE

•             THRUST RING

•             THRUST WALL

•             LUBRICANT

•             INTERMEDIATE JACK

•             CUTTING HEAD

•             PRESSURE TRANSFER RING ETC.

ADVANTAGES

•             it avoids the excavation or tranches.

•             quick set-up ,timely   finish of projects.

•             good quality control and good grade of pipe used .

•             can be remotely operated.

•             versatile in various ground conditions.

•             cost efficient for large length pipe .

•             small surface settlements.

•             reduced disruption or existing services.

•             environment  friendly.

•             less spoil.

DISADVANTAGES

•             Costly small lengths

•             skilled person is required .

•             Dewatering  of tunnel  path is usually required.

•             not feasible for nature of soil changes drastically  .