It is observed that settlement or sinking of reinstated trenches for underground utilities along and across the roads in Pune City in monsoon is one of the major causes leading not only to poor riding quality but also consequent damage to surface and subsurface section of the roads. Settlement and water stagnation result into potholes, accidents and discomfort to the citizens and immense criticism to the Municipal Corporation.
During the FinancialYear - the permissions for excavation oftrench for utilities,given by Pune Municipal Corporationad-measured km, out of total length of Pune Roads, which stands at km. Internal departmentsofPune Municipal Corporation,have excavated trenches for their services which further add to the length of trenching in the city.
There are number of utility agencies, external as well as internal who have theirservices laid below Pune Roads.
These agencies carry out diggingexcavation of the road for repairs maintenance andaugmentation of services. Earlier, there was no Apex Committee of Pune Municipal Corporationfor monitoring of the trenching activities and hence there was no systematic planning or annual program for laying repair of various utilities etc. within thePune Municipal Corporation departments or external utility service providers.
Hon. Municipal Commissioner has formed TheSteering Committee for co-ordination communication between various departments of PMC and service providers utility agencies. Add. Municipal Commissioner S, City Engineer of Pune Municipal Corporation, Chief Engineer Road , DMC Zone no to , SuperintendentEngineer of Roads, Drainage,Water supply,Deputy Police Commissioner of Trafﬁc,Pune City and the representatives of all external utility agencies service providers are the members of the Steering Committee.
Trenches excavated by various departments of Pune Municipal Corporation for laying downinternal utilities, are reinstated by the Road department or concerned Ward Ofﬁces. The external utility service provider deposit the amount for reinstatement work with Pune Municipal Corporation, based on astandard rate as decided upon by the General Body. The Road department of Pune Municipal Corporation, then, invites tenders for reinstatement of the utility crosscuts for such works. There is a certain provision in the budget for the reinstatement works. However, this amount is not commensurate with the total expenditure required during a particular year and hence there is a shortfall in the budget for reinstatement work of Pune Municipal Corporation. Additionally, the cost of reinstatement for the workscarried out by internal department of PMC is also not appropriated back to the Road department by that concerned department.
The contractor, thus appointed by Road department executes the works under the direct supervision of the JuniorEngineer of the Road department. The works are covered under defect liability period of one year from the date of completion of top asphalt layer.
SHORTFALLS PROBLEMS AND SOLUTIONS
The main problem observed during such works is enforcing the different conditions laid down at various stages for trenching and the reinstatement. There are speciﬁc tender conditions for protection of trench, lighting and providing safety to road users. But, these conditions are not fulﬁlled properly. At many places, heaps of earth rubble, material, pipes etc are seen lying on both sides of trenches for many days,creating problems for all pedestrians and vehicles. Hence, it is absolutely essential, to enforce the discipline by strict supervision and thorough penal action. The other inherent defect is in the backﬁlling process and materials used. These problem can be tackled by substituting Granular or other suitable material for entire backﬁll and compaction of pavement by vibratory rollers as per requirements small size equipment compactors required .
One more point of concern observed is the unauthorized excavations in the name of faults and emergencies by MSEDCL, Water Supply and DrainageMNGL etc. The permission for excavation for trenching is not given between th April to th September, except under emergency conditions.The utility service provider is not provided any speciﬁc location for dumping of the excess material within PMC limit.Such practices need to be stopped by drastic deterrent actions through Pune Municipal Corporation vigilance squads, resorting to legal action, if required.
The permission for excavation for trenching is not given between 30th April to 30th September, except under emergency conditions.The utility service provider is not provided any specific location for dumping of the excess material within PMC limit.Such practices need to be stopped by drastic deterrent actions through Pune Municipal Corporation vigilance squads,resorting to legal action, if required.
Junior Engineer whosupervises the work cannot give justice to the work due to other prior commitments. It is recommended, to appointaseparate Junior Engineer(at Zone level or Main department), exclusively for this work, during fair season and in monsoon season for pot holes and defect rectification of these works.
Use of Trenchless Technology:
Use of Modern day techniques of trenchless digging is an important solution for the problems faced for trench repairs. Techniques for Utility line installation,replacement,rehabilitation, inspection,location and leak detection are available in the market.These technologies requireminimum digging at the ground surface. Beneﬁts of Trenchless digging are as follows:
- Safer for the public
- Minimal trafﬁc impacts
- Minimal road repairs
- It reduces damages to valuable road surface
- It reduces the danger of improperly compacted excavation
- It saves resources and thus environmental degradation
- It reduces noise pollution
- It avoids annoyance to the public.
New Trenchless Construction Methods
- Impact Moiling
- Pipe ramming
- Auger Boring
- Pilot Tube
- Pipe Jacking
- Horizontal Directional Drilling.